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U.S. to require negative Covid-19 tests for international air passengers (reuters.com)
381 points by Element_ 5 days ago | hide | past | favorite | 438 comments





I have an interesting anecdote related to this.

As it happens, I currently have COVID. When I first noticed I was getting sick, I was scheduled to fly in the near future, so I got a rapid COVID test that delivers results in 15 minutes.

It was negative. I got another one, and it was negative too. I had thus intended to go ahead with the trip under the assumption I had a minor cold.

Later, a few days before I was to fly, I lost all smell and taste. Now I didn’t know what to think. I wasn’t particularly congested, and the loss of smell was total. I’d never experienced this before. Could both tests have been false negatives?

I delayed the flight (free of charge luckily, so no big deal) and got a test that had to be sent to a lab for analysis. A week later, the positive test result came back.

Take from this what you will. I'm not a scientist or a doctor and frankly there's nothing remotely intelligent I can say about the various tests out there for COVID. But if the rapid tests are as unreliable in general as they were for me, it’s sort of no wonder COVID is spreading like wildfire. I was very, very close to boarding a plane with an active case of COVID, and I would have if I hadn’t acted out of an abundance of caution.


Rapid tests are known to be unreliable and particularly have a high false negative rate. That's why all the guidance has been that rapid tests can be used to indicate infection but not rule one out, and none of the screening processes based on exposure and symptoms accept “but I also had a negative rapid test” as neutralizing a flag on any screening factor.

> I would have if I hadn’t acted out of an abundance of caution.

The bare minimum of caution with a rapid test is treating a positive as a true positive and a negative as an indicator that you need a regular test. That you understood your actions to be an abundance of caution demonstrates a failure to effectively communicate on some level (I'm not saying that you are culpable; the information is out there's but delivery is...mixed, even before considering how it is muddled by misinformation from various sources.)


I definitely think there's a communication deficiency or breakdown happening, because none of the medical professionals indicated to me that the rapid tests were that unreliable when it comes to producing false negatives. I also feel personally guilty for not having been as well-informed as I should have been. I'm just glad I experienced a tell-tale symptom (loss of smell/taste) and was able to act on it before boarding a plane.

Another interesting aspect of this is that prior to experiencing loss of smell/taste, I was more or less told by urgent care staff that I didn't have COVID, and they were pretty resistant to testing me -- hence I only got rapid tests. Yet I actually was right in the midst of an active case.


You mentioned it was a few days between the initial negative rapid tests and the positive lab test.

Would be interesting to know the result of another rapid test at the same time as the lab one.

Are they just flat out missing some infections, or do they require a much higher viral load to indicate positive?


> Are they just flat out missing some infections, or do they require a much higher viral load to indicate positive?

they do require a higher viral load than the pcr test to accurately show infection. the pcr test studies have shown to be 0-30% false negative later in the illness after symptoms have shown (when there are fewer antigens in the body). both the pcr and the rapid tests are expected to have a near 0% false positive rate though with most false positives being lab contamination or mishandling. even if the test is 50% false negative(not the actual number) it would still drastically slow the spread of the virus coupled with other measures. This is more of a defense in depth instead of a firewall; the swiss cheese layers of threat reduction.


Rapid tests are just a gamble if you want to save time/money/exposing others if you end up being positive.

If you're negative, you then have to get the actual test, but if you're positive you can probably start isolating now.


> if you’re positive you can probably start isolating now.

If you experience symptoms you should start isolating, regardless of the results of a rapid test.


That's true, but in this case the converse statement is also true that someone with a positive rapid test should start isolating even if symptoms are absent. It's this latter statement that you were replying to.

It’s the people without symptoms. Doing a regular test every few days will prevent at least some spreading if you are a symptomless carrier

> because none of the medical professionals indicated to me that the rapid tests were that unreliable when it comes to producing false negatives.

You're being very emphatic about this, but all you've described is that the rapid test failed in a single case (you). We expect a lot more failure than that from the slow test! Where is the idea coming from that you experienced egregious unreliability?


Well, he did take two rapid tests, which both produced false negatives.

What this tells us about false negatives depends on details he didn't mention, about how correlated the two tests were. Obviously, it was the same person each time - but was it the same day? Same test brand? Same clinic? Same tester?


> Well, he did take two rapid tests, which both produced false negatives.

That wasn't the impression I got; I understood him to say he took the same test twice. "Same test brand", as you put it.


I've had 2 nasal swab tests. The first one seemed to have taken a core sample of my eyeball or brain; the second one was not as bad. I have no idea if these were rapid tests or googles PCR tests. Messaging is poor for sure.

Separate variables. Either kind of test can be done with a nasopharyngeal swab, or without.

I can't count the number of communication breakdowns any more with Covid. Apparently to get any number of people on the same page about something is not possible. Even with the internet. Blame it on information overload, or perhaps apathy.

I hope when Biden takes office he does daily Covid briefings where they disseminate accurate knowledge which would include correcting previous things we thought we knew. I know democrats that actually watched the Trump briefings because there were actually intelligent people behind half the info. I think many people tuned out the moment he recommended injecting bleach - but there was still value in the briefings. It was something that I know a LOT of people actually paid attention to.


> I think many people tuned out the moment he recommended injecting bleach - but there was still value in the briefings. It was something that I know a LOT of people actually paid attention to.

This is an interesting comment re:communications and the messaging that reaches people. Trump did not recommend injecting bleach. He went on a rambling mostly incoherent recollection of a conversation he had where he was trying to learn what was being done. He was trying to sound smart. His comments were all questions to the med experts. "Is there a way we can do something like that?" "Are we going to check on that?"

Yet everyone jumped on it saying he "claims" or "recommended". And it became "truth" because news articles covering the press conference used phrases like "claims" and "recommended".

> "So I asked Bill a question some of you are thinking of if you're into that world, which I find to be pretty interesting. So, supposing we hit the body with a tremendous, whether its ultraviolet or just very powerful light, and I think you said, that hasn't been checked but you're gonna test it. And then I said, supposing it brought the light inside the body, which you can either do either through the skin or some other way, and I think you said you're gonna test that too, sounds interesting. And I then I see the disinfectant, where it knocks it out in one minute, and is there a way you can do something like that by injection inside, or almost a cleaning? Because you see it (COVID19) gets in the lungs, and it does a tremendous number on the lungs. So it'd be interesting to check that. So you're going to have to use medical doctors, but it sounds interesting to me, so we'll see. But the whole concept of the light, the way it goes in one minute, that's pretty powerful."

https://m.youtube.com/watch?v=33QdTOyXz3w


Presumably, Trump had been briefed about all of these things before giving the "inject bleach" press conference. The press conference is not the time to be asking questions you just thought about of medical experts. Not if you are the one giving the press conference at least. That is where the messaging fell apart.

> Even with the internet.

Especially with the internet. In the 80s the main media outlets reported the page and almost everyone followed. The internet now has a million “experts” for every actual expert, and even good opinions can doffer depending how you look at the facts.


I'm glad the OP made the correct decision in this case and hope they get well soon.

> the assumption I had a minor cold > the loss of smell was total

Since there does seem to be a messaging problem about the reliability of testing, I think it's worth emphasizing: if someone has symptoms of COVID, they should proceed as-if they have COVID. CDC guidance[1] is to isolate if you have a positive test OR if you have symptoms.

To do otherwise is to gamble with the health and lives of the people they meet, and the people those people meet, and so on. It may prove almost impossible to show who caught COVID from whom, but that doesn't mean that ignoring guidance won't lead to deaths. A statistical death is still the death of a real person, even if we can't put a name to them.

[1] https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/is...


To be clear, the order of events was such that I did not have loss of smell/taste at the time of the rapid tests. There was no indication at that time of anything that wasn't completely consistent with and expected from a cold, and I even encountered resistance when I tried to get tested prior to the tell-tale loss-of-smell symptom appearing (hence the rapid tests only at that point). I had a mildly uncomfortable phone call with an urgent care center where they discouraged me from pursuing testing because they didn't think I had enough symptoms.

I knew exactly from whom I had contracted whatever illness I had, and that person had also tested negative for COVID (upon further questioning, their test had also been a rapid one, and they too had not been informed of its unreliability for any negative determination).


> There was no indication at that time of anything that wasn't completely consistent with and expected from a cold

Unfortunately, I think these days symptoms of "just a cold" are enough reason to self isolate for long enough to reliably get through the Covid incubation period - which locally (Sydney .au) has been reported to occasionally be as long as 10 days or more.


The USA currently has nine million active cases. I actually think at this point if you have cold symptoms it may be more likely you have covid than a common cold.

(Though maybe someone has data in cold cases to clarify the cross over point)


> The USA currently has nine million active cases. I actually think at this point if you have cold symptoms it may be more likely you have covid than a common cold.

Your intuition is wildly off-base here. Nearly all of us catch at least one cold a year, mostly during the winter months. There are, quite literally, hundreds of millions of colds a year. There's also ~half a dozen viruses in circulation at any given time that cause cold-like symptoms, vs. one for SARS-CoV2.


The steps we are taking to reduce COVID spread also reduce the spread of the cold. I would be absolutely shocked if we don't end up having our lowest impact cold and flu season in decades this year. That isn't to say the grandparent comment is correct, just that you can't really use a comparison from prior years as an indication of how many people will get a cold this year.

In the first 6 months of 2020, Australian influenza deaths were down over 90%, attributed to Covid anti measures - mostly increased hand washing/sanitising, social distancing, and school closures.

https://www.abc.net.au/news/2020-07-23/coronavirus-restricti...

If we assume that's representative of a 90% reduction in flu and cold cases (not guaranteed, but probably a reasonable estimate to reason about), then perhaps instead of "hundreds of millions" of cases, it might be down to "tens of millions of cases" of cold/flu. So maybe 9 million Covid cases means any cold/flu symptoms are somewhere between 50% and 10% likely to be Covid - a virus currently killing ~1% of the people it infects.

I am certain the prudent thing to do in 2021 is assume _any_ cold/flu symptoms are likely to be a virus that's quite capable of killing you (and/or the people around you) and act accordingly until you are 100% certain it's not. (Which probably means 2 negative PCR tests ~10 days apart.)


> The steps we are taking to reduce COVID spread also reduce the spread of the cold.

...and cases are going up, so it's probably safe to assume that there are lots of colds being transmitted, as well. And as I said, there are many cold viruses in circulation, at all times.

Even if you believe that "the steps we are taking" are working, you have to assume that they're disproportionately effective for the common cold in order to make the statement the OP was making. Say what you will about SARS-CoV2, but it's more-or-less like any other respiratory virus in terms of transmission characteristics. There's no particular reason to believe that anything we're doing would stop rhinovirus or RSV, but not SARS-CoV2.


This doesn't follow at all because you are comparing the current state of laxing COVID precautions to the previous state of near zero cold precautions. For example, tens of millions of people are currently working from home and the workplace is one of the primary places colds spread. If we treated COVID like the cold we would already be on the other side of the pandemic because it would have already ripped through the population and millions would be dead.

> This doesn't follow at all because you are comparing the current state of laxing COVID precautions to the previous state of near zero cold precautions.

I am not. There are, right now, 5-6 cold viruses in common circulation. There is one SARS-CoV2 virus.

Nothing we are doing would be expected to suppress other respiratory viruses, but not this one.


>I am not. There are, right now, 5-6 cold viruses in common circulation. There is one SARS-CoV2 virus.

Yes you were. In your first comment you said "Nearly all of us catch at least one cold a year, mostly during the winter months. There are, quite literally, hundreds of millions of colds a year." Those are numbers in a normal cold year. This isn't a normal cold year.

>Nothing we are doing would be expected to suppress other respiratory viruses, but not this one.

I'm not sure where this line of argument came from as no one was arguing against it. The assumption is that these COVID precautions are equally effective against the cold, flu, COVID, and other similar respiratory diseases. This will lead to a huge drop in those non-COVID diseases as the precautions we are taking are so drastic compared to a normal year.


> Yes you were. In your first comment you said "Nearly all of us catch at least one cold a year, mostly during the winter months. There are, quite literally, hundreds of millions of colds a year." Those are numbers in a normal cold year. This isn't a normal cold year.

You can divide the number by any factor you want, but there are still ~6x the number of viruses out there causing colds. Even now.


>there are still ~6x the number of viruses out there causing colds

The variety of viruses is totally irrelevant to the original question of what are one's odds of having COVID based on having cold symptoms. The only piece of information that matters for that are the aggregate numbers and aggregate numbers from previous years are misleading.


> The variety of viruses is totally irrelevant to the original question of what are one's odds of having COVID based on having cold symptoms.

It is an essential factor, unless you make the (implausible) assumption that we have essentially eliminated all other respiratory viruses except for SARS-CoV2.


I like how you cutoff the my quote at the exact point that shows you how you are wrong. As I said "The only piece of information that matters for that are the aggregate numbers".

Whether there is 1 version, 6 different versions, or 1 million different versions of colds is irrelevant to your odds of having COVID when you show symptoms. What matters is whether there is 1 person, 6 people, or 1 million people with colds. The variety is meaningless. What matters is the aggregate number of cases.


> The variety of viruses is totally irrelevant to the original question of what are one's odds of having COVID based on having cold symptoms. The only piece of information that matters for that are the aggregate numbers and aggregate numbers from previous years are misleading.

It is an essential factor, unless you make the (implausible) assumption that we have essentially eliminated all other respiratory viruses except for SARS-CoV2.


I catch colds roughly 7-8 times per year. It sometimes feels like I have cold symptoms more days than I don’t. I currently have cold symptoms. If I had to isolate every day I had a cough, sore throat, congestion, or sneezing, I’d be under house arrest most of the year. I think it’s vitally important that we have accurate COVID tests that can definitively distinguish a case of the cold from a case of COVID.

At the end of the day everything is a judgement call. In this case I believe you're an outlier, guidelines are usually structured for the general case. Should you specifically treat every cold like it could be COVID? Maybe not, but should somebody else who gets sick only 1-3 times a year treat every cold like it could be COVID? That seems a lot more reasonable.

Not to mention it is wise and courteous to stay home and avoid exposing yourself to lots of people when you are sick regardless of if its COVID or not.


Not everyone can afford to stay home with minor illness. Not everyone will be employed if they stay home and can't "cover" their days off with measly 40 hrs a year of paid time for such purpose ( if they have any paid time at all).

This issue existed long before COVID. COVID is spreading partially due to this issue. Many people have no choice but work to avoid homelessness and/or hunger.


You should be tested for primary immune deficiency, based on the frequency of your colds alone. If you do have primary immunodeficiency, it is treatable with subcutaneous immunoglobulin, in most cases. Either way, it is treatable.

I am personally on subcutaneous immunoglobulin for two rare immune-mediated neurological diseases, and I have not had a cold in over 3 years, when I would get them a couple of times per year. It helps tremendously.

These are the 10 warning signs of primary immune deficiency in adults:

Adults

If you have two or more of these signs, speak to your doctor about a possible Primary Immunodeficiency.

1. Two or more new ear infections within 1 year

2. Two or more new sinus infections within 1 year, in the absence of allergy

3. One pneumonia per year for more than 1 year

4. Chronic diarrhea with weight loss

5. Recurrent viral infections (colds, herpes, warts, condyloma)

6. Recurrent need for intravenous antibiotics to clear infections

7. Recurrent, deep abscesses of the skin or internal organs

8. Persistent thrush or fungal infection on skin or elsewhere

9. Infection with normally harmless tuberculosis-like bacteria

10. A family history of Primary Immunodeficiency


That's a fair point, there's some more good discussion on this here:

https://www.nature.com/articles/d41586-020-03519-3

For the broader point, regardless whether or not someone is more likely to have a common cold or COVID given the same group of symptoms, I think the point stands that if someone has symptoms consistent with COVID they should proceed as-if they have COVID -- especially given the current case rate in US.


How many colds are you expected to catch on a year where the country is under lockdown, and many people are staying at home, or wearing masks?

There aren't great stats for the common cold, but the flu seems to be affecting only a quarter of the people hit by it in a usual year.


Are you sure? Do nearly all of us catch a cold _this_ year? I know the flu is way down this year due to covid-related behavioral changes. I'd be surprised if common colds are unaffected.

Thanks for the response, that’s a good point.

I agree with you, and that's largely why I wanted to share my story -- to illustrate that even without any tell-tale symptoms and multiple negative test results, you can easily still have COVID.

Thanks for sharing your story, it's useful to hear anecdotes. I also want to emphasize I was making a general comment and not intending a personal criticism.

The points raised by bigiain and mxcrossb are well-made, "cold-like" symptoms are COVID symptoms, the loss of taste and smell only occurs in some cases. CDC has a full list of coronavirus symptoms[1].

I fear that many are flying, socializing etc. when they are actually symptomatic (e.g. headache, sore throat) because they consider these minor symptoms, or perhaps they can just "hope for the best", but the severity of the symptom doesn't change whether or not someone is symptomatic.

[1] https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/s...


The heck is the point of a test if not to confirm or rule out covid? He took two tests, came back negative and assumed his "cold or covid" symptoms were cold until he had reason to believe they were covid. Other than the tests sucking everything in the fact pattern is perfectly reasonable.

This is a fair question.

Any test has a certain percentage of false positives and false negatives -- in fact, you can likely tune your ratio of false positives to false negatives depending on what your priority is. On a community level, the statistics from testing are essential for monitoring the spread of a disease, but on an individual level a test can still give an incorrect result, so shouldn't be the only factor when making decisions.

For an individual, if they have a negative test AND no symptoms AND no contacts with known COVID-positive individuals, then they can proceed as-if they don't have COVID and take standard precautions. However, if they do have symptoms, then that might mean further testing is required.

For anyone interested about testing, this graphic is essential:

https://media.nature.com/lw800/magazine-assets/d41586-020-02...

It shows the difference in test efficacy for different tests (rapid antigen, PCR, antibody tests) as a function of time from symptom onset.

Rapid antigen tests only have a narrow window of efficacy. If they come back positive, you likely have COVID, but if they come back negative you could still have COVID and could still be contagious.

This is also why many countries are requiring PCR tests prior to entry, because they are more effective than rapid antigen tests, although can also give false negatives, especially early after exposure.


In my opinion, the rapid test's greatest value is using it to screen asymptomatic people in a regular (daily or weekly) process. For example, a school would test a random sample of students each day. This could help catch any stealthy clusters. It's not perfect, but it's better than just looking for symptoms.

Tests have false negatives. The problem isn't so much the test, but rather the public which isn't fully qualified to interpret the results.

Biology and chemistry are complicated and messy. Sometimes signal is noisy or below the limit of detection.


It's also subtle in that while false negatives are common, false positives are rare (very rare). But general public don't get that subtlty and assume "the test isn't reliable" so a positive means they're not infected.

Source: numerous friends and relatives.


Almost no tests in existence can confirm or deny particular infection.

Think of them (and symptoms) more as odds updater. If you have 20 minutes to spare this video [0] by 3 Blue 1 Brown is a brilliant introduction to the concept.

[0] https://www.youtube.com/watch?v=lG4VkPoG3ko


Whether a test is positive or not depends highly on what type of test it is, and when you are tested relative to symptom onset. You can absolutely be carrying the COVID virus but still test negative. Heres a paper with a handy chart: https://jamanetwork.com/journals/jama/fullarticle/2765837

I think you testing negative was a combination of the rapid test being unreliable, as well as getting tested early with respect to symptoms.


Thanks for your anecdote. When SF was doing better and the possibility of big outdoor events with testing on the door were something that was being discussed, I looked at rapid tests together with some friends and the accuracy is really appalling. People relying on this to "safety socialize" may be one of the issues making cases rise in California, the math adds up. Many people reached to the government saying they should stop sponsoring and advertising rapid test sites because the false sense of security may be really doing more harm than good.

One of the rapid tests that we considered has, as advertised by its own manufacturer, a 10% false positive rate on basically all the population, and a 50% false negative rate even on symptomatic individuals with high viral load. Do the math, but using that type of test in something like for example a 100 person event or a restaurant will result in people being turned out of the door daily even if they were not symptomatic, and at least one or two people with high viral load being admitted into your place. I can't find the link of the test now, but there's better data about how harmful rapid tests are when not used together with PCR testing, for example here: https://www.bmj.com/content/371/bmj.m4941 and here: https://asm.org/Articles/2020/November/SARS-CoV-2-Testing-Se...

That's why most countries that really thought this through require a recent PCR test result for admittance.

It's really not clear what benefits rapid tests have if you don't have a model for population behavior. I think at lest the SF government is only doing them to save face now that the cat is out of the bag.


> But if the rapid tests are as unreliable in general as they were for me, it’s sort of no wonder COVID is spreading like wildfire.

Many rapid tests are indeed not accurate[1] but they still serve a purpose, depending on the sensitivity and specificity of the tests[2].

For the rapid tests with high sensitivity and you get a positive result, it's highly likely you have COVID.

For the rapid tests with high specificity and you get a negative result, it's highly likely that you don't have COVID.

And the public health measures of testing / contact tracing ONLY works if testing results come back quick. PCR tests are neither fast nor cheap, so those are not as effective in prevention of spreading because you don't do those all the time (slow + expensive).

Medcram has a good video talking about this. [3]

[1]: https://www.wsls.com/news/local/2021/01/08/cdc-study-shows-c...

[2]: https://en.wikipedia.org/wiki/Sensitivity_and_specificity

[3]: https://www.youtube.com/watch?v=h7Sv_pS8MgQ


I only have data points for two different testing orgs, but in my area, GoHealth charges $250 for a rapid test, and Color charges $110 for a PCR test[0]. So it seems like that's flipped from what you're suggesting?

The Color tests can even come back in 8 hours or so, if you're not too far from a lab and the lab isn't overloaded. Not as fast as 15 minutes, and certainly higher variance, but much more useful than 72 hours people normally assume.

Regarding false negative rate, Hawaii is accepting some of the rapid tests (like the aforementioned GoHealth test) for pre-travel screening, which is concerning.

[0] These are both without involving insurance at all. It's possible, though, that the Color tests are partially subsidised by Google?


Simply, $250 is a scam given the limitations of that type of test. Its simply a money grab from those unaware.

Its been known for months that PCR is the gold standard, and rapid tests are not. Rapid tests are good for surveillance but not diagnosis.


This rapid tests have a very high false negative rate. The result you get back should really be "You have COVID" or "You may have COVID, get a PCR test".

Rapid tests (aka: Antigen tests, or lateral flow tests) are high specificity, low sensitivity tests.

That means they’re biased towards the negative side: they’re unlikely to return false positives, but quite likely to give false negatives.

Such tests are useful for epidemiological studies, or for answering the “do I have Covid antibodies?” question.

But they’re not a reliable way to actually test for Covid. You need a PCR test for that!


Most countries which require a test for entry stipulate it must be a PCR test rather than a rapid (antigen) test. I’m currently in Lisbon waiting for the results of a 24h PCR test in order to board a flight to Azores, for example.

Rapid tests are at their most accurate when someone is at their peak infectiousness. Accuracy declines swiftly before or after that.

So the use you made of them didn’t fit their ideal use case, as you used them several days before travel.

Even then, with symptoms, I am not sure they would be enough to rule out a positive. The biggest use of rapid tests is finding additional positives that would not otherwise have been found.


> A week later, the positive test result came back

Which country do you live in that it takes a week for the PCR test to come back? It's around 24 hours here and I thought that was the case in all developed countries.

I hope you recover quickly!


I'm in the US. The test was taken on a Sunday evening at about 7:30PM, and the results were delivered via text message the morning of the following Friday.

My guess is there's a lot of variability in how long it takes to get results. I know folks who've taken the same test and they got results back within 48 hours.


There's a lot of variability, and it depends on how far you are from the lab the particular test center uses, how quickly the test center sends your sample to the lab, and how busy the lab is.

I've had two tests that came back in around 48 hours and one that only took 8 hours (US, SF bay area). 4.5 days seems pretty excessive (and frankly pretty useless) though!


South Africa here. I've known people that got their test back in less than 24 hours

Netherlands here, I routinely get them back within 8 hours after taking the swab. At work (hospital), we can get them within an hour if it's urgent.

The turnaround when I got a test just before Christmas in Melbourne was under 6 hours, only had to wait in line 5 minutes for the test too.

[flagged]


Please keep nationalistic flamebait, and any flamebait, off HN.

https://news.ycombinator.com/newsguidelines.html


Low effort clapback style comments should be directed towards reddit or Twitter

Yeah - you're right. I've got some angry snark going on here that isn't helping the discussion. I apologise.

They've been using these lateral flow tests in the UK quite a bit - particularly for university students returning home/to campus (or at least, that was the plan!).

But I'm not convinced the data on their effectiveness really supported using the tests in this way: https://twitter.com/deeksj/status/1340975400726478849

But it was a political "win".


> I have an interesting anecdote related to this.

Please don't do that.

There is enough knowledge out there about the various kinds of tests (PCR, antibody, antigene) and what they're good for and what they're not. It's perfectly understood that while rapid tests are, well, rapid, they're much less precise than PCR testing. However, they are often better than nothing (you can't give a PCR test to everyone who wants to visit relatives in a nursing home), so they serve to minimise risk, not to remove it. (They also have a tendency to be more likely to be positive while you're actually infectious, which is not the same thing as having symptoms.)

I really don't think we should be discussing personal anecdotes during a health crisis, when there's enough data around that we can actually look at.


There are many different rapid tests. Some are reliable and some are unreliable.

For the ones that are reliable (like Abbott's test), they are highly accurate at determining whether someone is currently infectious. So you could have been infected but not capable of transmitting to others yet. These tests would be highly useful for onsite testing, such as if airlines required a rapid test right at the airport.


The most common error with these tests is false application. Did you have someone else doing the swab? It has to feel like someone is poking at your brain.

If you don't mind, can you please share your age or a ballpark estimate? It seems like you are doing well and just had the minor symptoms.

Sure, I'm in my early 30s. I do believe I had a pretty mild case all things considered, and I'm pretty much fully recovered at this point but still plan to quarantine for another week.

What I experienced was basically indistinguishable from a mild cold except for the loss of smell and taste, which took over a week to show up after the onset of the initial symptom (a fever). While I know loss of smell can happen from non-COVID infections, I can say this is the only time in my life I've had a total loss of all smell and taste. I'm very fortunate that this total loss only persisted for a few days, and at this point based on my subjective experience my smell and taste senses appear to be normal again.


note that rapid test is still useful to confirm infection. But, yes, much more unstable for ruling out one

Note that even PCR tests have a relatively high rate of false negatives.

I hope you get well soon!

What entity approved the test for distribution?

If you still have yet to test positive for COVID you may not have COVID. A loss of sense of smell and taste is a common symptom of a viral infection.˜ [1]

[1] https://www.healthline.com/health/coronavirus-loss-of-taste-...


Yeah - so you should probably go to a political rally or concert or a nightclub or something!!!

:sigh:

This is awful advice for 2021. (Even though _technically_ it's correct.)

If you have a loss of smell/taste you should 100% assume you have Covid and act accordingly, get tested immediately, self quarantine for probably 14 whole days, and get retested at around 10 days.

If you have "mild cold/flu symptoms" you should assume you like;y have covid, and should get tested (not with a "rapid test") and self isolate until you get a negative result.

Truth is, even with no symptoms, you could have Covid. If you've been in contact with anyone who has cold/flu symptoms, or been to a place where someone with a positive covid test has been - you should get tested (and probably self isolate until you get a negative result).

From: https://jamanetwork.com/journals/jamanetworkopen/fullarticle...

Results: The baseline assumptions for the model were that peak infectiousness occurred at the median of symptom onset and that 30% of individuals with infection never develop symptoms and are 75% as infectious as those who do develop symptoms. Combined, these baseline assumptions imply that persons with infection who never develop symptoms may account for approximately 24% of all transmission. In this base case, 59% of all transmission came from asymptomatic transmission, comprising 35% from presymptomatic individuals and 24% from individuals who never develop symptoms. Under a broad range of values for each of these assumptions, at least 50% of new SARS-CoV-2 infections was estimated to have originated from exposure to individuals with infection but without symptoms.

Conclusions and Relevance: In this decision analytical model of multiple scenarios of proportions of asymptomatic individuals with COVID-19 and infectious periods, transmission from asymptomatic individuals was estimated to account for more than half of all transmissions. In addition to identification and isolation of persons with symptomatic COVID-19, effective control of spread will require reducing the risk of transmission from people with infection who do not have symptoms. These findings suggest that measures such as wearing masks, hand hygiene, social distancing, and strategic testing of people who are not ill will be foundational to slowing the spread of COVID-19 until safe and effective vaccines are available and widely used.


> Yeah - so you should probably go to a political rally or concert or a nightclub or something!!!

I don't recall saying that.

> If you have a loss of smell/taste you should 100% assume you have Covid and act accordingly, get tested immediately, self quarantine for probably 14 whole days, and get retested at around 10 days.

Did I say otherwise?

What I said was, if you lose your sense of smell and taste and then proceed to test negative twice for COVID, you may well not have COVID.

Rapid tests are right 80% of the time. Two rapid tests back to back are right 96% of the time. That means after 2 tests there's a 96% chance you don't have COVID, and a 4% chance you do. That doesn't mean you should tour your nearest retirement community.

You shouldn't go out anywhere if you're sick in the first place.

[edit] Even then, there's a 1% false positive rate on PCR, and a 4% false negative rate on 2x rapid test. Even at this point there's a 20% chance OP doesn't have COVID.


> Rapid tests are right 80% of the time. Two rapid tests back to back are right 96% of the time.

I doubt the false negative % for two tests on the same person at roughly the same time are uncorrelated. (For two reasons: It seems logical that they would depend on viral load, and/or other non-random factors; And if they were independent, we would be able to achieve arbitrarily high specificity by taking and processing multiple samples -- just three would get you >99% -- which doesn't seem to be happening.) So the false negative rate for two tests might be much closer to 20% than 4%.

> That means after 2 tests there's a 96% chance you don't have COVID, and a 4% chance you do.

This part is definitely not accurate. The real probability will depend on base rates and facts about the individual case.


They have already tested positive on their 3rd (PCR) test.

I don't understand why we don't implement the isolation procedures of countries that have gotten this under control, following these procedures for both foreign citizens AND US citizens:

- When you arrive in the US, you either spend two weeks at a government approved hotel, at your expense, which is monitored by federal agents to make sure you don't leave your room. You pay for room service for two weeks to get food. This is what Singapore does.

- If you don't want to stay at the government hotel, you agree to let the government track your cell phone for two weeks to make sure you stay in your home, and randomly call you twice a day to make sure you didn't ditch your phone. This is what Taiwan does.

As a plus, all the hotels near airports would be so thankful for all the forced business to make up for the loss of travel business.

They should have been doing this for the last nine months.

Edit: And obviously combine these rules with a relief bill that helps the industries that are hurt by these rules, or you know, everyone.


We do that in Australia too and its worked great. (Well, except for a notable quarantine breach 6 months ago due to mismanagement.)

The problem is all this is closing the fence after the horse has already bolted. The average person arriving into the united states is less likely to have covid than a resident. Currently 2.7% of the US population is infected with covid19, compared to 2.4% of people in the UK, 0.9% in Italy, 0.2% in Canada, and ~0% in Australia, NZ, Singapore, India, China, etc.

Almost all new infections in the US come from domestic transmission.


it should be departures from the US that require quarantine (pre-departure), not arrivals!

Where did you get those numbers? I read this comment earlier today, quoted 2.7% to a friend later, then realized I didn’t know what the source was and dug up your comment again.

Current US population numbers are around 328 million, while active coronavirus cases in the US are at 9.1 million. Divide the two and you get 2.7%.

Yep. Citation & world details here: https://www.worldometers.info/coronavirus/#countries

0% in India seems like you must have mistyped, or something.

India's infection rates are not comparable to the island nations that have successfully contained the virus.


I was surprised too!

Google took me here[1], which says India is down to 210k active covid cases at the moment. For a country with a population of 1.366 billion, thats only 0.016% of the population currently infected.

Its possible India's covid testing isn't telling the whole story - but they've apparently done 178 million tests to date.

[1] https://www.worldometers.info/coronavirus/country/india/


By comparison, Australia has done 12.1 million tests [1] for a population of 25.4 m people.

[1] https://www.health.gov.au/resources/publications/coronavirus...


Yes; India is probably missing the occasional case here and there. But given their daily case numbers have been dropping quickly, they're probably finding most people who have covid.

If India's real number of active covid cases was 100x the official reported numbers, they still wouldn't have as many active cases per capita as the UK and USA.


> I don't understand why we don't implement the isolation procedures

Because the largest driver of infections isn't foreign travelers. It's far and away due to the people who are already here.


Sure, but we got that new strain from a foreign traveler. It still cuts off a vector of transmission.

Maybe...

With all Australia's hard border closures and mandatory hotel quarantine, we've still had the UK Covid strain get out into the community. A cleaner at a quarantine hotel caught it from a returned citizen in quarantine (they're still not sure how), and spent 5 days in the community while infected. So far, it looks like we got very lucky, and the only person they've found that she infected is her partner.

From my point of view, the US (and UK and India and many other countries) have a categorically different problem to Australia (and New Zealand and Singapore and Taiwan and a few other countries).

We've _largely_ got things under control in Australia. Most of our cases in the last ~3 months have been hotel quarantine, with worrying incidences of outbreaks where it's escaped from quarantine but been tracked back and identified. Sydney currently has 3 clusters, with about 200 locally acquired cases between them in the last 4 weeks. I'm pretty sure every single one of them has been contact traced back to it's source of infection - and that contact tracing has also proactively got forward to get a very significant percentage of close contacts of infected people contacted and tested, and the places they visited while infectious identified, contact traced where possible (lots of venues are required to have covid checkin so people can be contacted an informed if they've potentially been exposed) - and any venues where they are not confident the covid checkins are comprehensive they publicise fairly widely and strongly encourage testing for anyone who visited during similar times.

This _only_ works because the numbers are so low. It all went to shit in Melbourne when a quarantine hotel breach happened and it got up over 700 cases a day, the contact tracing ability totally fell apart, and Melbourne went into a hard lockdown for several months to get it back under control.

In the US? Our approach just won't work. The virus is out and prevalent in your community. You have no hope of comprehensively contact tracing all of your positive cases, or identifying and mitigating all the venues they were in while infectious and contacting all the people who are at risk of exposure. The scale of your problem is totally insurmountable using the tools that work for us. If vaccination and/or herd immunity doesn't work out soon? You people might be totally fucked. ~1% of you will probably die from the virus, and quite likely a lot more will die from your medical system breaking under the load.


I agree with everything you said.

But it still wouldn't hurt to remove the vector of incoming travelers.


Sadly, I suspect it's like gun control. (I know, I know. Touchy subject, but hear me out - and please accept that I'm not trying to attack gun owners here.)

In Australia, there are few enough guns that reasonably strict licensing for owning/keeping/selling guns _mostly_ works. We managed to restrict "assault style" weapons early enough to have been able to do it before the prevalence of semi automatic weapons made it impossible. Gun violence here is several orders of magnitude lower that in the US by any reasonable measure. Not zero, but rare enough that "gunshots heard" is still newsworthy here.

If the US decided to try and get to that - it'd be a multi generation process to change attitudes and perceptions, and then to remove all the weapons currently in circulation. I don't believe there's the political or social will to even consider starting that. Your solutions to gun violence are fundamentally going to be different to Australia's.

(From my perspective, the news that my nieces regularly do "active shooter lockdown training exercises" in schools was inexplicable and horrifying. I kinda understand your historical "right to bear arms" - but I can't bend my mind into understanding how that's ended up at "there's nothing we can do about disgruntled teenagers getting hold of AK47s so we'll just teach our children how to hide under school desks and not make any noise, hoping that 'playing dead' will help them avoid getting shot". Not that I'm claiming too much moral high ground here, the most recent mass shooting in New Zealand was by an Australian. We have our fair share of fuckwits here too. Our main advantage is that most of those fuckwits do not have access to firearms when they fly into a murderous rage.)


I think is a case of a little too late. There's probably a higher risk of a traveller coming to US leaving with it, than arriving with it - currently. If this had happened 9 months ago, there might have been a chance of this working - with better leadership in other areas - as other child comments have pointed out.

> I don't understand why we don't implement the isolation procedures of countries that have gotten this under control

I'd hazard a guess that it's because they don't want to completely kill off tourism, an industry which is hurting pretty bad because of covid (see TSA arrivals screened https://www.tsa.gov/coronavirus/passenger-throughput)

No tourist would be interested in coming over to stay two weeks on their own dime locked in a hotel, only then to be able to do some actual traveling.


I don't think a lot of tourists are interested in coming right now anyway, given that our virus load is most likely worse than their home.

That being said, this obviously needs to be paired with a relief bill that helps those businesses survive.


I have family and friends in the US. A lot of friends. I've visited on average 2 or 3 times a year over the last 20 years or so. (Almost all "tourist" travel, maybe 10 or so "business trips" for conferences or vendor meetings, all of which had ect4ended time as a tourist visit included).

I have accepted the fact that I'm unlikely to see my family or friends there for probably at least 3 maybe 5 years.

They will very unlikely be allowed to visit here (Australia), and if they are will probably need to spend 14 days in quarantine upon arrival. Right now I am not allowed to leave the country (without a special exemption, which sure as hell does not get granted "to visit my little sister and her family!")

Even if I got that exemption, I'd need to join the huge queue of people attempting to return to Australia with severely limited inbound international travel capacity (we were only allowing 4,000 returning citizens per week, with the current concern overt he UK strain that's been cut to 2,000 per week). There are news reports of people who've been trying and failing to get back to Australia for 6 months or more, with flights being cancelled - and confirmed tickets of flights being cancelled (reportedly for people with higher priced tickets to fly instead...)

I hope the vaccines work out. I fear that they may not - either being less effective that advertised, being less effective against mutated strains, or being thwarted by anti vaxxers.


I spent New Years weekend in Palm Springs going on day trips to Joshua Tree National Park. It was PACKED. The park is absolutely beautiful and everyone should check it out sometime. It's an almost alien landscape.

My hotel was full as well in Palm Springs. The only thin open late and popping was the Indian casino. They did check temps and make sure people had masks, but otherwise it felt like Vegas on a normal busy weekend.


Considering how many immigrants and children of immigrants live in the US, even if the people you saw seemed very diverse they could maybe have been primarily US citizens not foreign tourists?

If you've recently had covid, it might be the perfect(cheapest) time to do it.

I suppose I haven't read definitive literature on the topic to be convinced but can you not catch it again, especially a different strain?

It still feels awfully risky to travel at the moment.


The anecdotal evidence I have says that you can be reinfected. I don't know if it was with different strains, but it's still troubling.

The anecdotal evidence says that a small number of people have been reinfected, out of millions. Statistically, the average person is likely immune for at least a matter of months, probably a couple years or more.

It's definitely a thing - a couple days ago I've read an article where they did interviews with three people who got reinfected here in Czech Republic. It also mentioned a fourth person who unfortunately died due to being infected for the second time.

So even for a country with just 10 millions of people you can still find enough people who had covid twice to interview - how we fucked up the second and third wave notwithstanding.


It's still not clear if a previous infection stops you from being an asymptomatic carrier, and we don't want more asymptomatic carriers.

> It's still not clear if a previous infection stops you from being an asymptomatic carrier, and we don't want more asymptomatic carriers.

It's as clear as it is for any other viral disease. For example, to my knowledge, nobody has ever done any kind of systematic study of whether or not infection with influenza protects you against asymptomatic reinfection with the same strain.

This is a level of paranoia that is unique to this particular virus.


> level of paranoia that is unique to this particular virus

This particular virus is >5x deadlier than seasonal flu, is significantly more contagious, and nobody has any pre-existing immunity.

Despite strong countermeasures, almost half a million people in the USA have died from the pandemic so far, and by the time we are through that number could potentially double.

It is the worst infectious disease threat since the 1918 flu (thankfully not quite as deadly as that one, given modern medical care).


> It is the worst infectious disease threat since the 1918 flu.

Well, no, actually. This virus is roughly on par with the 1957 pandemic in terms of IFR and per-capita fatality rate:

https://www.cdc.gov/flu/pandemic-resources/1957-1958-pandemi...

Regardless, as I said before, demanding that some kind of study be provided to prove that asymptomatic infection is prevented by natural immunity is so far beyond what we know about any other virus that it borders on the hysterical.


This virus is significantly worse than the 1957 or 1968 flu, causing many more hospitalizations and deaths despite much stronger countermeasures. But those two were indeed quite deadly, worse than seasonal flu, and if a similar flu emerges in the future it should be treated extremely seriously. Hopefully we can learn from our severe systematic mistakes in the Covid pandemic to better prepare for and react to future pandemics of flu and other pathogens.

>This virus is significantly worse than the 1957 or 1968 flu

Evidence please? The person you're replying to actually posted a CDC link.


The "CDC link" consists of a single paragraph.

The 1957 flu had less than half the IFR of Covid. It infected a smaller percentage of the world population than Covid is likely to, despite much less significant public health countermeasures, and a tremendous increase in medical knowledge in the past half century. It was likely significantly less contagious.

Death estimates in the USA are in the 100k range, vs. Covid which has already killed more than 400k (if we count using a similar estimation method) and will likely kill at least 200k more before it is through. (US population has more than doubled in the mean time, but we are talking about at least 5–8x as many deaths.) The difference in hospitalization rate is dramatic.

If you want a summary or some numbers about the current pandemic, try https://en.wikipedia.org/wiki/COVID-19_pandemic

It is really tragic that the abject failures of the US federal response have made partisans so heavily invest themselves in the claim that Covid is no big deal and we shouldn't worry about it.


> Death estimates in the USA are in the 100k range, vs. Covid which has already killed more than 400k

And if you don't cherry-pick which country you cite...

Globally, the 1957 flu caused about 1M excess deaths:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4747626/

Currently, Covid is attributed to ~2M deaths:

https://coronavirus.jhu.edu/

World population in 1957-58: about 2.9 billion people.

Current world population: 7.8 billion people.

https://www.worldometers.info/world-population/world-populat...

1957 flu mortality: 1,000,000 / 2,900,000,000 = 3 / 10,000

Covid-19 mortality: 2,000,000 / 7,800,000,000 = 2.6 / 10,000

...they're about the same. Mortality varies dramatically from country to country in both pandemics.


> Globally, the 1957 flu caused about 1M excess deaths. Currently, Covid is attributed to ~2M deaths

No, this is a disingenuous apples-to-oranges comparison. One is a post-epidemic estimate by independent epidemiologists, while the other is a confirmed-positive-death count subject to contemporaneous political pressure and institutional inability to confirm every Covid death.

The contemporaneous confirmed death numbers from any seasonal or pandemic flu are always many times lower than the final estimate, and decades ago it was probably at least an order of magnitude lower. The discrepancy won't be quite as dramatic with Covid today, because a tremendous effort has been made around the world to get Covid tests to hospitals. But it will still be a very significant undercount.

After a couple years once experts have had time to gather and crunch the numbers, the number of Covid deaths from a comparable kind of best-guess estimate is going to double or more. Even in the USA, we are probably missing on the order of 150–200k Covid deaths so far from our confirmed death counts. And the situation is broadly comparable in Europe. But many less developed countries have much less capacity for gathering and reporting accurate numbers, and only a tiny fraction of Covid deaths are being reported in many places.


> One is a post-epidemic estimate by independent epidemiologists, while the other is a confirmed-positive-death count subject to contemporaneous political pressure and institutional inability to confirm every Covid death.

...as well as almost certain over-counting due to extremely liberal criteria for "Covid deaths" (e.g. deaths within 30 days of a positive test, which is the standard in many areas.)

Point being: there's uncertainty on the "confirmed-positive death count" in both directions and you're assuming that it's a strict lower bound.

Just today, the WSJ published an excess-death study that put the number at 2.8M, worldwide (or 3.5/10,000):

https://www.wsj.com/articles/the-covid-19-death-toll-is-even...

Higher than the JHU numbers, but still within reasonable statistical error of the 1957 pandemic estimates.

> After a couple years once experts have had time to gather and crunch the numbers, the number of Covid deaths from a comparable kind of best-guess estimate is going to double or more. Even in the USA, we are probably missing on the order of 150–200k Covid deaths so far from our confirmed death counts.

Well, now you're just making things up. Also, again: see the WSJ study above. Even if you count every excess death this year as Covid...it's about the same as the 1957 flu season.


covid-19 is not 5 times deadlier than the flu. It is about twice. The IFR sits at ca 0.19. Flu is about 0.1.

Covid scare-mongers using inaccurate and outright false data to cause panic, terror and so much confusion that the public is left to choose what to ignore and what to follow, are causing much more damage than covid deniers are. The fear of going to the hospital among people with other ailments come to mind. There was an article in Nature the other day on the 300% increase in stillbirths in UK due to lack of in-person pre natal care. Another delightful side effects of the extreme fear propaganda.

No one listened to the idiot deniers anyway. They never were the problem.

Source: https://onlinelibrary.wiley.com/doi/10.1111/eci.13423.


0.19% is much lower than even the low bound of consensus scientific estimates; the Ionnidis paper on which he bases these estimates has also received significant direct criticism. In my opinion Ioannidis is a disingenuous hack who has thoroughly discredited himself during this pandemic, and from what I can tell his agenda-driven Covid punditry is popular on Fox News and Breitbart but not taken seriously by professional epidemiologists.

The US CDC's best estimate of IFR as of a planning scenaario document from September was 0.5% for people aged 50–70, and 5.4% for people aged 70+. (This is not the best source available, but miscellaneous journal papers could be criticized as cherry-picked.) Adjusted population IFR varies from place to place, depending on the proportion of seniors, people with pre-existing health problems, access to medical care, etc., but nowhere in the US is it as low as 0.19%.

If you want a credible widely cited meta-analysis, try e.g. https://link.springer.com/article/10.1007/s10654-020-00698-1 from December which calls Covid "far more dangerous than influenza", and estimates the IFR to be at least 5–10x higher.

> The estimated age-specific IFR is very low for children and younger adults (e.g., 0.002% at age 10 and 0.01% at age 25) but increases progressively to 0.4% at age 55, 1.4% at age 65, 4.6% at age 75, and 15% at age 85.

> As shown in Fig. 6, population IFR (computed across all ages) ranges from about 0.5% in Salt Lake City and Geneva to 1.5% in Australia and England and 2.7% in Italy.

> Supplementary Appendix O: [We estimate that during winter 2018–19] the population IFR for seasonal influenza was in the range of 0.04% to 0.08% – an order of magnitude smaller than the population IFR for COVID-19.

* * *

> increase in stillbirths in UK

The UK has royally screwed up most aspects of pandemic response. Just like Brexit and everything else the Tories have had their hands on in the past few years. You don't see the same problems in other wealthy island nations like New Zealand or Taiwan.

(With the notable exception that the UK has done a decent job sequencing a large collection of viral samples.)


0.19% is entirely in line with other credible estimates:

https://www.who.int/bulletin/online_first/BLT.20.265892.pdf

> Across 51 locations, the median COVID-19 infection fatality rate was 0.27% (corrected 0.23%): the rate was 0.09% in locations with COVID-19 population mortality rates less than the global average (< 118 deaths/million), 0.20% in locations with 118–500 COVID-19 deaths/million people and 0.57% in locations with > 500 COVID-19 deaths/million people. In people < 70 years, infection fatality rates ranged from 0.00% to 0.31% with crude and corrected medians of 0.05%.

But this is a meaningless debate. Your own preferred source makes it clear that the "average IFR" is heavily dependent on population demographics (i.e. in the very next sentence after the one you quoted:

> our results indicate that about 90% of the variation in population IFR across geographical locations reflects differences in the age composition of the population and the extent to which relatively vulnerable age groups were exposed to the virus

You're also completely misinterpreting Figure 6 from that paper. It is showing that their model of age-specific IFR correlates well with observed differences in reported IFRs. It is not claiming that those reported values are meaningful in the absolute -- in fact, all of the "reported" values seem to be higher than the model by a factor of ~2-4, and they're substantially higher than the numbers cited by the WHO bulletin.

(and yes, I know you don't like Ioannidis, but this is a metareview, not original research. Also, not liking someone doesn't make them wrong.)


Maybe, but it's still not clear if a previous infection stops you from being an asymptomatic carrier, and we don't want more asymptomatic carriers.

Still doubt that that many people will travel long distance because of the hassle, the risk of getting stranded or having to deal with the local overwhelmed health system. Anecdotally I know a couple of people in Europe that travelled quite a bit during summer because it was an unique chance to see some historical places e.g. in Italy without the mass of tourists they are usually overrun by. But that was a tiny fraction of the usually very travel happy social circles of mine.

But for the US I think the main attractions are the big cities and the national parks. The former are not really tempting to go to atm and the latter you usually want to go in groups and they seem so vast that I don’t think it is that big of an opportunity to go there when there are few tourists. The only people I know that traveled in between continents in the last months did so for family reasons and it was a huge pain for everyone with multiple flight cancellations, chaos with ever changing immigration requirements that not even the officials can keep up with, self-isolation, etc.


Haha, maybe if you want to go camping or something? Not too many tourist attractions are open these days...

Speaking as an Australian, I'm not allowed to travel to the US at all right now, unless I'm moving there permanently. Keeping everything open (and thus keeping covid rates high) isn't doing your international tourism sector any favours.

Tourists have been banned since March I believe.

This was international arrivals at LAX August 11 (the worlds third busiest airport):

https://imgur.com/a/fFsVSXf


> No tourist would be interested in coming over to stay two weeks on their own dime locked in a hotel, only then to be able to do some actual traveling.

Depending on where they're coming from they'll have to do that on the way home, so they're not interested in coming anyway.


But there is no tourism in the U.S. right now. ESTAs and Visas haven't been approved since April.

That's not true, ESTAs are being approved as usual.

Our media tells us that in the US, wearing masks is a policitized topic, which is crazy.

Noone I know is considering a US vacation since mid 2020.


If you've stayed in a hotel during the pandemic, you know that the tourism industry is doing abysmally anyway.

This would require a level of coordination and leadership at CBP that we just haven’t seen, at least under the current administration.

Yep, this is working great in Taiwan.

Before you get on the plane you need a negative test, but even then there is a mandatory 14 day quarantine. When you arrive you are required to have a SIM card. During quaratine, they track your device and call randomly one or twice a day to be sure your phone is on you. Breaking quarantine is a big fine (up to $33k USD) and there is a carrot if you complete quarantine without any incidents ($500 or something?). Individuals are provided quarantine housing if they can't pay but employers are expected to pay (e.g, workers from Indonesia).


Hope the two random phone calls are video calls and not just audio. Otherwise people would leave the phone with someone at home to answer for them.

> Otherwise people would leave the phone with someone at home to answer for them.

Or they would just do the sensible thing and not break quarantine.


I assume this is combined with some kind of mandatory GPS tracking. The GPS tracking knows the phones location and the call confirms the user is next to their phone.

Covid isn't remotely impactful enough to create de-facto internment camps.

If you don't want to spend two weeks locked into a hotel, you can stay at home instead.

[flagged]


They were not asleep, they were deliberately letting the car drive off a cliff because they thought admitting there was a cliff there would make them look weak.

Probably also contributed by the fact that the opposition pointed out that they should avoid the cliff so the only option left is to intentionally drive off it.

Also (to extend this metaphor to all three modes of transport), they were sure that - should any cliff present itself - the greatest nation on Earth will not fall down it, but will boost off and fly towards the sunset.

Nah they weren't asleep, but they were standing on the wrong ship, looking backwards.

Because this is a violation of the 5th amendment and the 1st amendment right to peaceably assemble.

The Supreme Court has already ruled that neither of those apply at the border. Nor does the 4th.

Would you agree with the court when it determined that the rights of black people were different between northern and southern states, or that internment of the Japanese was legal during WWII? The supreme court has been wrong on many issues for decades on end throughout US history. They haven't all of a sudden become infallible in the last 20 years.

They certainly aren't infallible, and were wrong on those rulings. But until someone with standing brings a new case, that is the law as it stands.

If you're hinting that what is legal is not necessarily right, it seems odd to fall back to this position when the original comment about the 1st and 5th amendment are legal, not moral.

Instead of just mentioning the 1st and 5th amendment, it may have been better just to say that the US has a culture of privacy and personal freedom.


You are taking jedberg's comment too literally

> The Supreme Court has already ruled that neither of those apply at the border. Nor does the 4th. reply

This is an extremely overbroad generalization.

The supreme court may or may not rule that forcing someone to be surveilled by federal agents in order to travel by plane is unconstitutional, or it may not. And it may be right or wrong. My qualm is legal and moral.


Isn't there an argument from principle that violating a quarantine during a pandemic is not actually peaceable?

>I don't understand why we don't implement the isolation procedures of countries that have gotten this under control, following these procedures for both foreign citizens AND US citizens:

Because that would be communism!! /s


Why are Canadians so scared of communism then, given they haven't done this? Or Germans? Or Finns?

My impression is that media plays a huge role. The few, often foolish critical voices get an improportionate of attention and thus influence.

I know its probably crazy to ask, but tell me where in the US Constitution does the federal government have the power to force me into a hotel at my expense

I know in "times of emergency" people seem to think the constitution is suspended and the government as "unlimited power" but last I checked Emperor Palatine was a fictional character, and saying "Singapore does" well Singapore is an Authoritarian nightmare IMO, one i do not really want to replicate here in the US. I pass taking public policy lessons from Singapore


It's part of protecting the borders. The Supreme Court has already determined that anything within 100 miles of the border is the "border zone" and gives the government broad authority to enforce border protection within that zone.

Also, it could reasonably argued that it is part of their "protect life" job.


That is a stretch of the reading of those provisions, the court has generally (and wrongly IMO) allowed Federal Law enforcement to stop people with in the border zones to establish if they crossed the border illegally, once Citizenship is established then normal protections snap back into place

Even at border crossing the government has been allowed to seize Devices and other things but they generally can not prevent a US Citizen from entering, they can stop you from bringing your stuff, but they cant stop you (outside the limited questioning detainment certainly not 14 days) unless they have an arrest warrant or some other cause of action to arrest you


I agree that they were wrong. But that is how things stand now.

And they do have a cause to detain you -- you might be carrying a deadly virus. Until you can prove otherwise, they can detain you.


That is flipping due process on its head, the state has the duty to prove I am a danger to others, I have not duty to prove I am not

Having a position that I have to prove my innocence is completely devoid of any due process and is unconstitutional


Pandemic+unknown disease status is proof of danger.

You can argue that isn't a high enough standard, but it's a pretty clear one, and given the exponential spread, it's a real actual danger that can be controlled at the point of entry.


Given that Virus and Biology have no obligation to be compatible with various national and international laws, it is upon human society and governments to work around the virus.

Thus, for e.g., people in South East and Far East Asia learned from the earlier pandemics and voluntarily wear face masks to protect themselves and those around them even when one has "just a cold or a cough".

People also agreed to socially and physically distance when asked. The messages from scientists and doctors have been enough proof of the dangers that the virus poses.


That is fine, my problem is recently we have just be ignoring the constitution when it is deemed to be a problem

The fact remains the federal government has no constitutional authority nor do most state government.

If we need "pandemic response" authority then we need to amend the constition to add the power to the government not just simply declare it so because "The Experts™" have declared that is what is best for us.

if that is the measure of our rights, we have no rights at all. If rights can be stripped with a simple declaration of emergency, on which there is no power to challenge that declaration then we have no rights at all

To believe the government will not use this unprecedented event for which they have usurped a wide range of never used before power in ever increasing ways is naive and ignores all of human history.

It will not be long before the seasonal flu or cold will be enough to warrant draconian measure and limited on personal freedoms, or be used for privacy invading policies like contact tracing all the time (which will then be used for Law Enforcement like in Singapore)

it amazes me out people can not see what is next, or maybe than can but simply believe the promise (false promise) of safety is more important than liberty


Good thing that you're not in charge of anything.

Personal attacks are not cool here, regardless of how wrong someone is or you feel they are. We ban accounts that do that. If you wouldn't mind reviewing https://news.ycombinator.com/newsguidelines.html and taking the intended spirit of the site to heart, we'd be grateful.

Edit: looks like we've had to ask you this more than once before. Please don't do it again!


This was not a personal attack. This was an attack of their position.

A: "We should be doing [stupid thing] X" B: "Good thing you're not the one deciding."

B is not a personal attack. The entire premise of the point is that it's because of what they said/think, not something personal about that particular individual.


> That is a stretch of the reading of those provisions

Any, you know, the government and law enforcement have _never_ been known to do that...

"It's not 'collection' if we permanently record every phonemail/textmessage/email ever sent. It only counts as 'collection' if a human reads/listens to it!"

:sigh:


They wouldn't prevent you from entering. They'd just make you quarantine once you did.

> the court has generally (and wrongly IMO)

Well thank god you are not in charge of Policy in the US.


Borders (and airports) are already a constitutional twilight zone. Just to get into (or sometimes out of) one I have to go through an X-ray scanner or manual groping that on its face would violate the Fourth Amendment. But at the same time, nobody is forcing me to go there.

A similar requirement has been enacted in Canada and what has happened is that Canadians with covid can't return home to Canada and are stuck abroad. It really gives some teeth to the "do not travel" recommendation - if you get covid abroad you can't come home until you test negative. If you get covid at home and then go abroad you can't come home until you test negative. I think people who previously would have travelled and just risked it will be a lot more careful now since they can't get home if they are sick with covid. Instead of dozens of flights per day entering canada with covid cases we now have zero [1].

[1] http://www.bccdc.ca/health-info/diseases-conditions/covid-19...


Small correction: you can't board a flight to Canada. You're always welcome at a land border without a test report in hand. In which case you'll be required to spend 14 days in government quarantine.

You spend the 14 days in quarantine either way - land or air. And it's not 'government quarantine' for most people - it's just a hotel room, airbnb or wherever your approved plan says you're going to quarantine.

"As has been the case for months, all travellers will have their quarantine plans reviewed by a government official and, if not suitable, will be required to quarantine in a federal quarantine facility."[1]

Canadian citizens and permanent residents always have a right to enter. Presumably if you come to a land border without a negative test, you won't be trusted to self-quarantine properly and will be whisked off into a federal facility.

https://www.canada.ca/en/transport-canada/news/2020/12/pre-d...


I think it's highly dependent. I came to Canada a few months back, completed the Federal and Provincial quarantine plans. All I got at immigration was a "be careful" and 2 calls from the province asking if everything was ok.

I've heard that that is generally the case. I was merely pointing out that if you show up at a border crossing without a negative test despite it being required, you likely won't be trusted to "be careful".

I'm totally ok with covid19 positive Canadians being stuck an unable to return home until they test negative. That's fair.

But people are getting stuck because they can't get results back in the 72 hour window. That's really not cool.


>I'm totally ok with covid19 positive Canadians being stuck an unable to return home until they test negative.

I am not; your home country should never deny you entry. You're telling a citizen he is not welcome in his own country, is that how you want to treat your citizens?

Quarantine is warranted but denying entry has a weird taste to me


It's an imperfect solution. But thousands of people have left to the beach in Mexico, Florida, etc. We aren't talking of people that got surprised by COVID in March, we are talking of people that bought a plane ticket in the middle of the pandemic, traveled abroad for vacation, and are now inconvenienced by the fact they need to get tested to come back.

Not everyone is traveling to the beach on vacation. There are numerous valid, serious reasons people need to travel.

Assuming that every Canadian outside of the country was on vacation is simply wrong.

I'm also in the same situation with my home country. I was born there, has the country passport, don't mind 2 week quarantine, commercial airlines have expressed interest but they are simply not allowed. Only a pitiful amount of repatriation flights are done.

I can't believe it's harder to go back to my home country than to get a visa to the US. I'm lucky I can stay long-ish term in the US but many many others are screwed.

I understand the country is underequipped to deal with a lot of people coming back and it's better to protect many more people inside but I do feel forgotten sometimes. What's the point of having the citizenship then if I can't even come home?


I’m assuming this is Vietnam as I have friends going through the same issue. Citizens of Vietnam and they are on a 6-9 month waiting list for a repatriation flight with the gov’t basically saying “if you can stay where you are you can’t come here”.

They can’t even even pay for a commercial flights and quarantine like other countries.

And because Lunar New Year celebrations are coming up, repatriations flights have been cancelled until after as they are concerned with all the travel within the country.


There's a big problem of Vietnamese who are stranded and jobless in Japan -- they lost their (mostly travel-related) jobs, cannot pay tuition, and cannot return home:

https://mainichi.jp/english/articles/20210103/p2a/00m/0na/00...


I guess the situation with Vietnam is more unique that I thought.

This is an unrelated rant since the absurdity of the situation got to me. If you can hear the rumors about the reasons why there are fewer repatriation flights in January though, it definitely takes the cake.


How do you ensure safe travel for a covid positive person?

I am terrified of the possibility of this being retained after the pandemic and expanded to cover other maladies. There already is a concept called medical inadmissibility, but it only applies to foreign nationals. It really concerns me that we are not applying it to Canadians as well.

There are labs that guarantee < 72-hour turnaround times for travel. It costs extra but hey, that's life. This pandemic has been around for a year now so if it was that important to travel, it's worth paying extra for the test.

In Nevada it takes 5 days. Canadians are getting stuck there.

In Central America - could vary a lot by country.


> In Nevada it takes 5 days.

You're telling me there are no private labs that'll do it quicker? We have plenty in the Bay Area. Sounds like a market failure.


Not every place in the world is going to have PCR tests with results in a 72 hour window. There are going to be lots of Canadians falling through the cracks.

72 hour? In Florida you only pay out-of-pocket if you get the 1 hour test...

The 30 minute tests are antigen tests. The 72 hour tests are PCR tests. Antigen tests can basically only detect the virus if you're currently contagious. PCR tests can detect the virus before and after you're contagious. Airlines typically require the 72 hour PCR tests.

Here (Sydney Australia) PCR tests are mostly getting results within 24 hours, often as low as 14 hours.

72 hours is a system problem, not a fundamental timeframe for the test.


"But people are getting stuck because they can't get results back in the 72 hour window. That's really not cool."

That's their problem. Should have thought of that before going on vacation, etc.


Because they had a magic 8 ball to predict this outcome?

Given 98% of cases are internal spread, I just don't think it's warranted.


I don't think you need an 8 ball to predict that you shouldn't travel during this global pandemic -- especially in the past 6 months when it's all hit the fan.

Tough luck to those who get stranded, I say.


Not everybody outside the country is on vacation. How about a little empathy for your fellow countrymen.

Totally agree! My comment was intended to those travelling for recreational purposes.

You can pick up new variants abroad though. That’s better discouraged.

Now they are in countries in the Caribbean that have managed the virus relatively well and are overloading their public health system because they urgently need tests. Canada is just creating a problem for poorer countries while gaining very little - there's barely any community spread. If a Canadian returns home from the Carribean, on average both countries will have less covid.

Governments has been telling people for months not to go on vacation, that is correct, they should have thought of that before leaving.

They also gave 2 weeks notice so if you went somewhere and didn't think you could get a COVID test, there was still time to make it back home before the ban started.


Not everybody outside the country is on vacation. There are plenty of valid reasons to travel.

If only these people would suffer that would be alright - it was their mistake. But rich countries should not make poorer countries pay for the bad decisions of their own citizens. Policy needs to be guided by data, not emotions.

Keep in mind individuals can test positive for months after being infected but are not at risk for spreading the virus. It really should be a negative test or 14+ days after a positive test.

That sounds inconvenient. I’ve been ordered to stay at home off and on for almost a year, and it’s been inconvenient too.

So because you suffered an inconvenience in the comfort of your own home it makes it ok to strand Canadians overseas?

That's mature.


my friend's father passed away from covid three weeks after contracting it at a curling tournament which they obviously shouldn't have held, even in a small town in the middle of nowhere. he was 65 years old and had just retired. being dead is also not cool.

I think I can be upset at both.

Only 2% of cases are coming from outside of the country, so this seems mostly like a political thing than actually being useful. There's a lot of lower hanging fruit to get a 2% reduction. This seems too heavy handed in places where it's not currently possible to do a 72 hour test.

At the very least give some options to those can't meet the requirement. These people have to quarantine two weeks after returning anyway - I just don't see the logic behind this move.


> These people have to quarantine two weeks after returning anyway - I just don't see the logic behind this move.

Well, presumably a lot of the people taking foreign holidays are covid sceptics. So expecting 100% compliance with all quarantine rules would be pretty naive.


The authorities follow up and the fines can be huge, even including potential jail time.

I mean 100%, no, but enough to move the needle on the number of infections? I doubt it.


totally ok with letting them get stuck abroad. It's weird that everyone is freaking out about people travelling when the airports remain open and the guidance is totally about what ppl do inside the country. If you must keep the airport open(IMO should close them), let people leave and don't let them come back. If they leave, it's their problem (and unfortunately, some other country's). Stay at home.

For non-essential travel, I can 100% agree with you.

Not all travel is non-essential though (to a varying degree based on your belief of what "essential" encompasses).


There are risks to traveling internationally, especially during a global pandemic. Getting stranded at your destination happens to be one of them.

I know a woman who traveled from the US to Trinidad last February to care for her mother. She is still stuck there today. Fortunately, she has internet and an understanding employer.


You're in an incredibly privileged position to be in to say such a thing.

I recently had to get a negative COVID result to travel to Hawaii to see family. Hawaii only accepted tests from a very limited number of providers which complicated things, but after some effort I made an appointment and got a test. The rest of the process was very painless. We all had to keep masks on for the entire flight of course since there was no requirement that we all have a negative result before getting on the flight but it was comforting to know that nearly everyone else on the flight would have had a negative result so as to avoid the mandatory 14 day quarantine upon arrival.

If you enter Mauritius you have to get four tests in total over several weeks. Islands are taking advantage of their isolation to get this pandemic under control.

Madeira has been very successful during all of 2020 with not letting it escalate.


I don't at all see how this is relevant to the United States in 2021, when COVID-19 is almost completely prevalent, and we require universal vaccination to exit out of the pandemic - International travel restrictions seem meaningless to me now - though they would have been invaluable in January 2020, and maybe even February 2020 - right now the major risk of COVID-19 infection is inside the United States. A handful (or heck, even hundreds) of people coming into the country won't make any difference when we have thousands of new cases a day regardless.

There's a reason Epidemologists don't put much stock in travel restrictions once a pandemic is well underway around the world - they don't do much good.

But - generally, having widespread (ideally very sensitive) COVID testing for any type of travel outside of the home is a good thing. We should have it universally available. Ideally <$10, something that everyone could do weekly, or even daily if they travel a lot.

Just unclear what the focus on international travel is all about here.


Some rationale for blocking international travel - preventing the spread of international variants, and preventing the destination country from being overloaded by incoming infections.

Most nations aren't getting the vaccines yet. Vaccination distribution and delivery require complex logistics. Nations that don't have a good public healthcare infrastructure need time to gear up. Vaccinations have just started and are being given in a phased manner. Blocking International Travel (or at least mandating a 14 day quarantine) helps keep variants in check.


Ironically, it's in countries where there is partial vaccination that we haven't the greatest risk - partial pressure against the virus will select it for stronger ability to be vaccine resistant. It's why it's so important to give everyone two doses of vaccine as quickly as possible and vaccinate the entire population, so you don't have the virus spreading, mutating, and potentially evolving to become vaccine resistant and then endemic in the population. We only get one really good chance to hit herd immunity.

But - longer term - agree with you - wouldn't it be awesome if we had full-viral scans of travelers, international or otherwise - would shut down flu pandemics as well (most of them are imported from other countries).


I think all domestic and international travel should have this requirement at a minimum. Nobody should be on an airplane without a recent negative test. Or working in a factory, hospital, or other indoor environment for that matter, it would be great if essential workers could all routinely get tested once or twice a week, though maybe that's not feasible.

I don't really get the international focus of this either, but it seems like a step in the right direction.


>But - generally, having widespread (ideally very sensitive) COVID testing for any type of travel outside of the home is a good thing.

It would also be good to test for any disease before traveling. Flu, cold, just stay home for those, too


This is no surprise, although according to CDC research, this only reduces the infection rate among these passengers by 5-9%.

A lot of EU countries require their own citizens of their countries to get a COVID-19 PCR test prior to entry. A lot of times, this has to be paid out of pocket abroad.


What research is this? As far as I've been able to tell, CDC hasn't conducted a single randomized survey on any large group, but has only collected convenience samples.

Also keep in mind that due to compounding (keeping these people from infecting others on the plane and at home), the effect extends beyond the people prevented from traveling. You can also speculate that detectable infections are more transmissible during the journey.


Is that 5-9% of total passengers or 5-9% of those that have covid at the time?

Anecdote from a German that visited Spain to see the family: Spains government requires <72h old negative covid test before entering the country, with 6000€ in fines if no test can be presented. Also, a form about symptoms etc had to be filled out.

After arriving at Valencia, Spain, there was a big line where we had to show the form's result QR code only. Not a single passenger was asked for the covid test.


I've heard that the vaccine doesn't make you less likely to transmit COVID - just less acute symptoms. So getting the vaccine doesn't really help other people - just you. From this perspective, this doesn't make much sense (unless the objective is to make $ for the corporations).

You heard wrong. Nobody actually knows if you can transmit after getting vaccinated or not. Thus far anyone who claims otherwise is a liar.

There is some evidence that some of the vaccines prevent transmissions, but we need more study before we can make a statistical determination.

We know why other vaccines have failed to stop transmission. The reasons those vaccines didn't stop transmission do not apply to the covid ones. However there is a lot we don't know about biology so until we have better evidence no expert will state that the vaccine stops transmission even though many believe it will.


It was just published today that in Israel, where around 20% of the population has already been vaccinated with the first dose, they're beginning to see clear evidence that vaccinated people do not transmit it others.

I'm glad it's happening (better late than never), but they really should have started doing this a year ago.

Tests weren't widely available a year ago. 3-6 months ago maybe.

In fact a year ago, exactly, the existence of COVID was still being denied or downplayed by the Chinese government. Very few people in the US even knew about it, and only if very plugged in to Chinese social media or non government sources.


I'm pretty sure it was being widely covered (and acknowledged by the chinese) in late January during Chinese New Year. https://www.nytimes.com/2020/01/29/world/asia/coronavirus-ch... At the time the US evacuated ~200 people from Wuhan, flew them to LAX (well, landed at a nearby air force base), made them stay in isolation, then monitored them as they returned home for 2 weeks.

>in late January

what I said:

>In fact a year ago, exactly

Key word is exactly, as in Jan 12, 2020.


I think the times reported (in a serious article) that China reported the first death on or around that date (https://www.nytimes.com/2020/01/10/world/asia/china-virus-wu...). I certainly recall seeing coverage of it before that although it was very muted.

But just a few days before, the Times is a lot more rosy, https://www.nytimes.com/2020/01/08/health/china-pneumonia-ou...

"There is no evidence that the new virus is readily spread by humans, which would make it particularly dangerous, and it has not been tied to any deaths"

Clearly, between Jan 8 and late Jan, was the time of massive increased interest, so we're not really in disagreement.


It was on my radar in mid January; I know this clearly because it made me choose not to buy plane tickets for a big family celebration scheduled for the end of February.

Well I'm talking about the 12th, China was rounding up and arresting doctors talking about it and making them sign apology statements. You might be thinking of a week or two later.

That's possible; I don't remember the exact dates, just that it was at the "I really need to buy tickets" timeframe for the end of Feb.

The USA was doing 500k tests/day back in May, and over 1m tests/day by July. Probably couldn't have happened earlier than that, but it would definitely have been feasible mid last year.

Source: https://ourworldindata.org/grapher/full-list-covid-19-tests-...


In order for a policy like this to be workable, you need tests to be widely available in the countries people are travelling from because the whole point is to test people before departure - and they simply weren't in most non-US countries.

Wrong. It was all over Reddit but people laughed over it.

and the current situation is that US has more cases than anywhere else in the world.

Per capita it's really most of western Europe and the US that are struggling, and the US is doing better on vaccinations so far while it has had a higher case and death rate than most but not all of Europe. It's rather misleading to just cite a total confirmed case count.

https://boogheta.github.io/coronavirus-countries/


There are only a handful of countries not western Europe or the US where I would trust their numbers. Of the list Vietnam is the only surprise.

Trust means their official numbers within a reasonable margin of error of correct. Nobody have perfectly accurate numbers, but the ones are trust are generally not miscounting by enough to worry about.


An issue with PCR tests is that most of them use a cycle threshold of 40, which produces way to many false positives.

https://www.nytimes.com/2020/08/29/health/coronavirus-testin...


Just to clarify, the linked article isn't really talking about false positives. It's talking about people who are carrying the virus, but perhaps aren't contagious due to it being only small amounts.

"False positive" isn't really an accurate term there.

If there's no virus, you're not going to be able to amplify it. A too-high threshold may detect non-contagious levels of virus (still a concern, if you're in the early pre-symptomatic days of an infection) or non-infectious virus particles left over post-infection.


Doesn't this presuppose that the only thing the test can detect is the virus itself and not things that highly, but not perfectly, correlate to it?

Not really, no. They specifically pick genomic sequences believed to be unique to SARS-CoV-2; they're specific enough to distinguish between SARS-CoV-2 and the other known coronaviruses, let alone less related viruses.

top 10 unknown fact about startup

This article doesn't mention PCR tests, so perhaps we're being smart enough to accept the often-more-relevant-for-infection-control antigen tests for this purpose. (I'd not yet bet on it, given how bureaucracies have made almost every wrong choice so far, but: maybe?)

But also: if PCR false-positives are a concern, the cycle standard can be reduced, or the reporting expanded to include the cycle on which a test turned positive, so that "positive" tests that are likely dubious/marginal/past-infection can distinguished from "blazing active infection".


The rapid antigen tests have a significant problem with false-negatives: the BMJ reported that Innova tests have 49% sensitivity.

That makes it pointless to use as a border control - for every two cases, at least one gets through. (Or, potentially much worse, under this system: I throw away my positive tests and show whatever false negative one I have).

You ideally want to be conservative and permit some false positives at an effective border control, because you don't want to risk infectious cases getting through and causing an untraceable national breakout.


Even tiny sensitivity would be better than nothing – or something that's so slow & expensive it's impractical.

But other antigen tests purport to have 90%+ sensitivity.

And the kinds of "PCR positives" they miss are often cases that are no longer infectious, anyway: lingering viral fragments, rather than live full-virus shedding.

So: ideal for border-control & creating other internal gradients that help suppress the worst active cases. The perfect should not be the enemy of the very good.


> Even tiny sensitivity would be better than nothing

Not if you imagine that one case on a plane = potential super-spreading event, the plane touches down and then newly infected people go in every direction.

Your hypothetical test with tiny sensitivity is pointless, in this regard: it has a (less than) tiny chance of preventing each risky passenger. In my view, any kind of low-sensitivity testing before departure is theatre: it won't make any difference in preventing new infection from breaking out.

The government of the country that I am in agrees, and requires a negative PCR test.


Well at least false positives are much better than false negatives.

How easy is it to find out the cycle threshold the provider use?

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