
Japanese man tests positive for coronavirus again - koolba
https://www3.nhk.or.jp/nhkworld/en/news/20200315_13/
======
ulrikrasmussen
A commenter on Reddit claimed that rebound effects are known among patients
that have been treated with antiviral medications, and that that could also be
a possible explanation:
[https://www.reddit.com/r/Coronavirus/comments/fjuj24/5075_of...](https://www.reddit.com/r/Coronavirus/comments/fjuj24/5075_of_covid19_cases_are_completely_asymptomatic/fkpnet1/)

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wycy
The entire theory of the solution to coronavirus hinges on an assumption that
it will eventually pass once a critical mass of people have been infected and
developed immunity. The handful of stories like this trickling out might imply
that the immunity assumption could be incorrect.

What would be the ramifications of this? Could corona just bounce around the
population for the rest of time, putting everyone at a high percentage chance
of dying or requiring hospitalization multiple times a year? Could it be the
kind of thing that comes back as a novel form every year like the flu? Could
we be seeing covid-20, covid-21, etc ad infinitum, with high mortality/low
life expectancy just being a new reality of life?

EDIT: If this were the case, and immunity is very shortlived after the virus
is gone, maybe it could be contained through giving everyone an extremely
frequent regimen of vaccines until this particular strain is out of
circulation?

~~~
__blockcipher__
I’m unaware of _any_ illness where some measure of immunity is not developed.
I find it incredibly hard to believe that recovering from covid infection does
not afford some level of immunity.

I do wonder if recovery due to anti-virals prevents or weakens immunity,
however.

~~~
nostromo
Right. If our immune system didn't get better at fighting something, you would
remain infected forever or die from it. Reference HIV as an example of a virus
our immune system could not fight.

If anyone is getting better (and 98%+ of people are) it's because the immune
system can effectively fight it.

~~~
__blockcipher__
Wow, I didn’t even think of it like that. That’s a great way to reason about
it that makes it immediately clear. Thanks!

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gnfisher
It is unclear if he was symptomatic in the first positive test. I have read at
least some of the tests are capable of giving false positives. Could this have
been the case here?

~~~
learc83
It's more likely that the tests that cleared him were false negatives.

~~~
baxtr
I understand that false negative PCR tests are almost impossible?

EDIT: for those down voting. What about this paper then?

[https://pubmed.ncbi.nlm.nih.gov/32133832/](https://pubmed.ncbi.nlm.nih.gov/32133832/)

~~~
jennyyang
30% chance of false negative which is why they do 2 days in a row, which bring
it down to 9% chance of false negatives.

~~~
PeterisP
Sooo, if you release a thousand patients as cured based on these tests, you'll
have 90 false negatives...

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JanSt
Reinfection could not occur in SARS-CoV-2 infected rhesus macaques

"In this study, our results indicated that the primary SARS-CoV-2 infection
could protect from subsequent exposures, which have the reference of prognosis
of the disease and vital implications for vaccine design.Importantly, the
unsuccessful rechallenge in NHP models suggested that the re-positivity from
discharged patients could not be due to reinfection. It needs to consider more
complicated issues to find out the causes."

[https://www.biorxiv.org/content/10.1101/2020.03.13.990226v1....](https://www.biorxiv.org/content/10.1101/2020.03.13.990226v1.full.pdf)

That's a pretty good sign for an equal response in humans.

~~~
dwaltrip
Looking briefly at the study (I only skimmed the beginning), it seems they
attempted the reinfenction quite soon after the recovery from the initial
infection.

This doesn't tell us anything about how long one may be immune for afterwards.

Does anyone have knowledge about the length of periods of immunity (or lack
thereof) in various infectious diseases?

~~~
rimliu
IIRC immunity for coronaviruses typicaly is 6months-two years. And I am not
sure , but if you get reinfected after that, once you clear the second
infection your immunity will last longer yet.

~~~
scotty79
So Boris Johnson will just have to re-infect 50% of UK citizens every 6-24
months while perfectly protecting seniors to keep his idea of herd immunity.

~~~
ajuc
And increase number of hospitals 8 times :)

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dynamite-ready
In the current social climate (i.e, false positives perhaps being somewhat
less likely, especially in a contrived situation like a cruise ship full of at
risk patients) if we assume that the subject truly was infected, cleared, then
infected again in such a short time window, what would that mean for all
current containment strategies?

~~~
Blahah
It essentially means we need a vaccine to create immunity at scale, and will
need to have fairly strict measures in place until that can happen.

~~~
the_af
I don't understand how a vaccine would work if prior exposure to the virus
doesn't prevent re-infection :/ Honest question, no snark intended.

~~~
jshevek
Well I think it wouldn't be an 'inactivated' or 'attenuated' vaccine, but we
have other vaccine types designed to trick the body into developing the
readiness for an immune response. I don't know if they could work for this
type of disease.

Edit: I glanced at vaccines on Wikipedia, read the following on conjugate
vaccines. Maybe we will develop a new technology to do something similar with
viruses, training the immune system to recognize the virus by linking it to a
toxin?

> _Conjugate—certain bacteria have polysaccharide outer coats that are poorly
> immunogenic. By linking these outer coats to proteins (e.g., toxins), the
> immune system can be led to recognize the polysaccharide as if it were a
> protein antigen. This approach is used in the Haemophilus influenzae type B
> vaccine.[41]_

~~~
the_af
Interesting, and thanks for replying. I realize I know very little about
vaccines beyond the elementary-school-level basics (even though my brother is
an immunologist... maybe I should ask _him_ ).

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phonebucket
While reinfection is ominous and unwelcome, the fact that individual cases
like this are newsworthy makes me hopeful that it is a rare phenomenon.

~~~
jshevek
That's what I was thinking. Especially if there is a genetic factor involved,
and we can determine that only a small percentage of the population have it,
then we could still achieve a level of herd immunity.

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nimish
False negatives are a huge issue here. The tests aren't that sensitive. If it
was truly recurrent we'd see a lot more than one person since the disease is
so contagious.

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standardUser
What has caused the slow rate of transmission in Japan?

It seems that the number of cases in Europe and the US keeps climbing (despite
limited/late containment actions), but Japan seems to have it under control,
comparatively speaking.

~~~
ericdykstra
Many companies implemented work-from-home policies very quickly, almost all
public events (sports, standardized tests) were canceled, schools and sports
gyms closed, and some companies that didn't go to remote work had employees
stagger commute times so trains would be less crowded. This all started, iirc,
while the number of cases was still in the tens (not counting the cruise
ship).

It is also more accepted to wear face masks, as many people have pollen
allergies so it's quite normal, and there is less direct physical contact
between people overall.

I remember reading that the number of flu cases was about half that of a
normal flu season because of the precautions everyone was taking, which points
to a high percentage of people doing their part to help prevent the spread.

~~~
chadlavi
This is the big difference: people _doing their part_ to help instead of, say,
panic-hoarding or obstreperously insisting on going on as if nothing were
happening.

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pmoriarty
Here's what Ralph Baric, an epidemiologist from the University of North
Carolina Chapel Hill, had this to say on episode 591 of _This Week in
Virology_ [1] a few days ago:

Ralph Baric: _I saw some very interesting data from Stan Perlman the other
day, who has been looking at serum neutralization titers of MERS patients from
the Middle East kingdom of Saudi Arabia area and it 's quite intersting that
people peak fairly quickly with high neutralization titers but then they wane
over the next year to almost background levels or just slightly above
background levels by the second year, and with MERS there have been several
reports of people who have seroconverted. They were RT-PCR positive and their
serum neutralizing titers and even ELISA titers went to almost zero within a
few months._

Baric: _And it has not been studied and it should be studied, and this is the
contemporary human Coronaviruses -- nobody knows how they maintain themselves
in human populations. They don 't undergo rapid antigenic variation like
influenza. There's not 115 common cold or corona virus type genotypes or
whatever they're called, serotypes. Sorry Vincent, I just butchered the
coronaviruses._

Vincent Racaniello: _That 's ok._ <laughter>

Baric: _So one hypothesis is that they cause a transient protective immune
response that wanes quickly and then they can reinfect and cause mild upper-
respiratory tract infections and that 's how they maintain themselves. So it
is quite possible.. there's been a number now of reported cases in China of
SARS2 infections where people were documented to be infected and recovered.
They were RT-PCR negative. They went home and they became reinfected a month
later or so._

Baric: _In this case the United States has sufficient cases that we can
actually track the serologic responses of the individuals and their general
immune.. both B- and T-cell responses after infection and we can get a handle
on the long term immunity that may be elicited after infection._

On the other hand, from a letter read on an earlier _TWiV_ [2]:

 _I 'm an infectious disease doctor and would like to point out an important
factor in diagnosing this infection (and all respiratory pathogens that use
nucleic acid probes for specimen collection). This is of particular concern
now that China has transitioned to a much more problematic clinical diagnosis
based more on clinical symptoms than PCR testing._

 _While it may seem trivial how a health care worker jams a swab in to someone
's throat or nose, technique is important. If anterior naries (front of nose)
swabs or side of mouth swabs are done, rather than the true posterior
nasopharynx or oropharangeal swabs, the sensitivity drops dramatically._

 _We have shown this to be true repeatedly with diagnosis of influenza and
respiratory pathogens, and I am disappointed that it has not been mentioned
more in discussions about the PCR tests, missing the diagnosis in people who
are positive and negative then positive again._

 _We often see people admitted from the ER with the perhaps carelessly
collected flu test who miraculously are flu positive by the time they are
admitted. Like so many cultures and diagnostics in infectious diseases,
specimen collection and handling is critical._

 _I warn my patients about the unpleasantness of a nasopharangeal swab and
jokingly tell them that if it doesn 't cause a wincy-face reaction we haven't
collected specimens from where the viruses reside._

[1] -
[http://www.microbe.tv/twiv/twiv-591/](http://www.microbe.tv/twiv/twiv-591/)
about 15 minutes and 50 seconds in to the program

[2] -
[http://www.microbe.tv/twiv/twiv-588/](http://www.microbe.tv/twiv/twiv-588/)
at about 1 hour and 38 minutes in

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geocrasher
Edit: Is this lousy testing? Or mutation? It'll be interesting to see how this
develops.

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aaron695
I chose to assume it was not a re-infection and it just came back in a rare
case, which is very possible.

If not, we are dead and it's pointless planing around collapse of society.

It makes much more sense to assume we have a solid ( IE at least a year in
most cases) herd immunity.

Planning around no herd immunity is like planning in depth around bankruptcy
at round one funding.

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jrockway
I was under the impression that one typically becomes immune to diseases like
this, but apparently that's not the case? Does anyone have any reliable
information here? Is this particular instance what we would typically expect,
or can it be explained by test inaccuracy, something unusual about this
person, etc.?

~~~
gvjddbnvdrbv
The Chinese say their are two distinct strains in circulation.

Tests are not perfect.

Plenty of explanations. Most of them quite uncomfortable.

~~~
jeltz
Do you have a source for that? Because the does not really match my reading of
the data on [https://nextstrain.org/ncov](https://nextstrain.org/ncov).

~~~
barkerja
[https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX...](https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540747/all/Coronavirus_COVID_19__SARS_CoV_2_)

> Preliminary evidence suggests two strains of SARS-2-CoV circulating: one
> associated with milder illness (~30%), the other with severe illness (70%).

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jeffreyrogers
What is the rate of false positives given a positive test result for these
tests?

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chiefalchemist
Isn't it possible his negative was a false negative? Or even his initial
positive was false while having other flu-like symptoms? Then his negative was
accurate. And finally he became infected properly.

~~~
raarts
I've also read reports of similar cases that turned out to be just
administrative errors. Mixed up identities or just misspellings.

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Leary
I have read many reports of people improving during the middle of the disease
when it suddenly takes a bad turn (respiratory failure/cardiac arrest). I
wonder if that is at all related to this.

~~~
pvaldes
> I have read many reports of people improving during the middle of the
> disease when it suddenly takes a bad turn (respiratory failure/cardiac
> arrest)

Medecine is not an exact science. There is a lots of things that can suddenly
go wrong in the background.

There is the possibility of secondary infection in hospital with opportunistic
resistant microbes.

And there is also the possibility of foul game, that can't be discarded and
would be difficult to prove. Is a low probability but real risk. Unfortunately
angels of mercy appear sometimes, often enough to have their own category.

[https://en.wikipedia.org/wiki/Angel_of_mercy_(criminology)](https://en.wikipedia.org/wiki/Angel_of_mercy_\(criminology\))

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sputr
dr. Campbell[1] (the guy on YT explaining the situation every day) said that
this seems to be because some people do not clear the virus effectively the
first time ... and are picked up again on a later test, but that no proof has
been shown that people can get reinfected and will probably be immune for at
least a year.

[1]
[https://www.youtube.com/user/Campbellteaching](https://www.youtube.com/user/Campbellteaching)

~~~
ardit33
He started getting symptoms again, which is the most worrisome part. It is not
just simple virus is still lingering around, but it caused an infection again
35+ days after he had it once.

I hope this is just a fluke

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petilon
Is it feasible to create a vaccine against a virus if even infection with a
live virus and catching the disease does not give you immunity?

