
New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity - bookofjoe
https://jcm.asm.org/content/early/2020/05/07/JCM.00941-20
======
cerebral_oasis
I took this antibody test through LabCorp on Friday and tested positive. I
have been in strict (see: paranoid) isolation with one other person since
March 7 and haven't felt sick or anything close to it since then.

I did have what I thought was a strange flu/cold early February with a sore
throat, post-nasal drip, wildly varying body temperature, and lower back
pains. In hindsight those are COVID-19 symptoms.

the person I live with took the same Abbott Architect antibody test from
LabCorp today so that we can compare results and hopefully eliminate any false
positives.

more info on the test:
[https://www.corelaboratory.abbott/us/en/offerings/segments/i...](https://www.corelaboratory.abbott/us/en/offerings/segments/infectious-
disease/sars-
cov-2?fbclid=IwAR2lTmGoOE89ddmQKP2Kxr0kCOF1D0uUI3Xs5NHiJbXZRIIPCwW3yqotIR8)

FDA article from 05/07/2020 on serology test performance including the Abbott
Architect from OP: [https://www.fda.gov/medical-devices/emergency-situations-
med...](https://www.fda.gov/medical-devices/emergency-situations-medical-
devices/eua-authorized-serology-test-performance)

~~~
jrockway
Good anecdote. I also had a "weird cold" in February with symptoms that are
unusual for me but typical of COVID-19, and have been waiting to get the
antibody test. I kind of expect it to turn out the same way. (Otherwise, I
would really like to figure out what the "weird cold" that everyone had in
February was. Because it sure was weird, and everyone I know had it.)

~~~
y-c-o-m-b
"Weird cold" in February checking in. I did not have any temperature
variations or fevers, but I got struck with a fatigue like no other. For the
first time since I was 3 years old, I took afternoon naps three days in a row
because I was just completely wiped out. It's rare for me to take a nap at all
(happens maybe once a year)! It took two weeks to get out of this fatigued
state. My other symptoms were "chills-like" sensations throughout the day,
post-nasal drip and burning feeling in my chest/lungs but very minimal cough.
My child did have COVID-19 symptoms back around Feb/March (can't remember
exact time-frame) and I even wrote about that here on HN. Maybe I should take
this test.

I still think there's a possibility this virus was already in the US before
2020. I don't think they ever found a cause to the "mystery respiratory virus"
in Virginia from July 2019:

[https://www.nbcwashington.com/news/local/health-officials-
to...](https://www.nbcwashington.com/news/local/health-officials-to-give-
update-after-respiratory-illness-sickens-dozens-at-virginia-retirement-
community/135890/)

> Three people have also died, but Dr. Benjamin Schwartz of the Fairfax County
> Health Department said Wednesday afternoon that those who died were "older"
> and had complex health problems. Officials don't yet know the extent to
> which the respiratory illness contributed to their deaths, he said.

~~~
jrockway
I agree with you on being open to thinking that COVID-19 arrived earlier than
was initially thought. When I first shared my "weird cold" story on HN, the
consensus was that I was a crazy person and there was no way that could be
COVID-19. There would be more deaths if it had been here. But now there are
some deaths, and a large number of people with "weird cold" stories, and it
really makes me think that a lot of people have already had this. Maybe the
doctors at the time didn't recognize it as COVID-19 (I didn't when I had my
weird cold). Maybe the numbers that we see now are just wrong; i.e. the
recorded cases we have are just the tip of the iceberg (and if you tested
everyone every week, we would have hundreds of millions of cases).

Or maybe that weird cold was just a weird cold and nothing more. It seems
unlikely to me, but I'm open to it. I hate to make public policy suggestions
on anecdotes... but someone should really look into that weird cold. Everyone
in New York had it. It sure is weird.

~~~
xyhopguy
people say that because .25% of the population in NYC are dead from covid. we
dont see those numbers here -- if it was widespread in feb, what caused the
discrepancy?

~~~
jrockway
I guess we need to know the total number of cases to figure out what the
deaths mean, and until everyone has gotten an antibody test, we can't know
that total number.

To make the numbers work for the "weird cold" in early February case, I guess
we have to work backwards. Assume that when we went into lockdown was the
actual peak, 8 million people in New York City had COVID-19. That means that
there is one death for every 500 cases. Then we have to pick a reproduction
rate, which I have no idea how to pick, so I'll say that it increases by 1.5x
every day (so on day one you have x cases, then on day 2 you have x + 1.5 _x,
then on day 3 you have x + 1.5_ x + (1.5)^2x, etc. Going back a month from
March 20 (which is approximately 30 days, and when a lot of people report
their "weird cold"), that would mean we'd expect around 8 million / 383500 =
20 cases on Feb. 20. With 1 death per 500 cases, you'd have 0 deaths at that
level.

I know I've pulled these numbers out of my nether region and so they are
likely very wrong. But with some back-of-the-envelope math, I think we can
have some sick people in February without a lot of deaths.

Obviously my 8 million total cases in NYC number is too high, and the 20 cases
on 2/20 is too low for me and my friends to be those cases. But that
exponential can be tweaked to make something plausible. If we make it 1.2
instead of 1.5, then we should have had about 7000 cases on 2/20, and that
means around 14 deaths. That seems quite plausible to me. So I dunno. There
was a weird cold. It's weird. It could mean anything.

I signed up to get an antibody test. 1 test is not data, but it will be very
interesting to see the results.

~~~
not2b
1 out of 421 NYC residents have died, based on today's numbers, and recent
serological tests estimated that 20% of residents were exposed. If that's
right, then the death rate would be about 1/84, or about 1.2%. But I've seen
other claims that the exposure rate in NYC is higher, which would give a lower
fatality rate.

~~~
taeric
Don't forget to factor this breaking through to long term care facilities.
From the last I looked at this, if it had not hit long term care, the number
of deaths would have been low enough that it may have gone undetected longer.
(In WA, 92% of the deaths are still folks over sixty! I don't know the numbers
for how many of them were in long term care.)

Which is to say, you can't just look at the population death rate and really
appreciate just how dangerous this is for older populations. The CFR for over
sixty is a staggering 15% in WA. That is ridiculously high and completely
masked if you look at all cases.

~~~
postingawayonhn
> Don't forget to factor this breaking through to long term care facilities.

If they're not taking any precautions (because there's no knowledge of the
virus in the community) then it can spread to those types of facilities very
easily. In New Zealand where only 1,500 people have have COVID-19 (likely to
be very accurate, 200,000 tests have been conducted) there's already been two
outbreaks in nursing homes.

~~~
taeric
Certainly. I am not implying that we should just let it run its course. Just
as I would not let any disease we have a vaccine for loose in a nursing home
without the vaccine.

I just think the total IFR actually undersells how dangerous this is.

------
charliea0
It is refreshing to read a headline about an antibody test that conveys useful
information about specificity and sensitivity rates. This really helps to
inform about how useful a test could be for serological surveys.

Well done Hacker News.

~~~
bookofjoe
I wrote the headline from information in the abstract.

------
rindalir
It's interesting -- in the paper it says that the samples they used to assess
the sensitivity (it was a different population for specificity) were from
people who had (mostly) been elderly and hospitalized, and that they do not
know how it would perform in subclinical or asymptomatic cases. I admit being
super not-objective about my reading, since I had this test done last week and
came back negative despite losing my sense of smell completely in late March -
early April (I live in Boston and was exposed to people who tested positive).
It will be interesting to see more data on the Abbott and Roche tests on the
subclinical / asymptomatic population.

------
ardit33
I took this test this Friday (Quest Direct) in NYC and tested negative.

In late Feb. I had a 'flu like symptoms' with fever and massive headache for
few days. What worried me later is that I had the 'can't taste anything'
symptom a week later. No coughing though.

If you read online, you see people swear they had it at some point this
winter. So, if you had a 'flu like' symptoms in Feb or early March, perhaps it
was just that...

It cost $110 and personally I think it was worth it... (it is a reminder
myself to be more careful as I can still get it)...

~~~
kevin_thibedeau
If the government was serious about homeland security and restoring the
economy they would be subsidizing testing full boat.

~~~
ikeyany
The government has made it clear that this is about politics and business, not
safety or public health.

~~~
mikekchar
Not to put too fine a point on it, even if it is about politics and business
it's practically crazy not to fully fund these kinds of activities. The ROI is
staggering. It's pretty hard to imagine a price tag where it doesn't work out
well for you.

------
barbegal
> We tested 1,020 serum specimens collected prior to SARS-CoV-2 circulation in
> the United States and found one false positive

This gives 95% confidence intervals of between 0.0% and 0.5% false positive
rate.

~~~
ghshephard
Okay - I'm going to reveal my statistics ignorance here - but if they did get
a false positive, how does 0.0% fall within the range of possibilities (or is
that allowing for it might be 0.0499..% or lower?)

~~~
samatman
All of the sibling answers are correct, but ignoring another possibility: that
the timeline is simply wrong, and SARS2 was present in the US early enough
that the "false positive" is in fact a true positive.

Which can't lead to a "true 0%", since there's no such animal. But it could
mean that all of the tests gave correct answers, in the trial.

~~~
squnch
They could be testing this on five year old samples.

~~~
MarkusQ
From the article:

> Specificity samples were derived from de-identified excess serum specimens
> sent to our clinical virology laboratory in 2018 and 2019.

So...not five years ago, and it is even possible that a significant number
were from late 2019.

------
ummonk
The sample sizes are too small to claim such high specificity and sensitivity
without any error bars.

~~~
mercurywells
> The sensitivity of the assay from the estimated day of symptom onset for the
> 125 patients included in our chart-review study was 53.1% (95%CI
> 39.4%-66.3%) at 7 days, 82.4% (51.0-76.4%) at 10 days, 96.9% (89.5-99.5%) at
> 14 days, and 100% (95.1%-100%) at day 17 using the manufacturer’s
> recommended cutoff of 1.4.

> The sensitivity from the date of PCR positivity was: 88.7% (78.5-94.4%) at 7
> days, 97.2% (90.4-99.5%) at 10 days, 100.0% at 14 days (95.4-100.0%), and
> 100.0% (95.5-100.0%) at 17 days using the manufacturer’s recommended cutoff
> of 1.4.

------
pgcudahy
There seems to be no analysis of whether these are neutralizing antibodies.
The idea of using serology for immunity certificates or "golden tickets" is
never going to go well. Even with 99.9% specificity, if the population
prevalence is 1%, 10% of positives will be false positives. If in real world
testing, specificity is 99% and population prevalence is 1%, then 50% of
positives are false positives.

~~~
wtvanhest
Would you or someone else mind expanding on this thought a little? Why does
99.9% specificity mean that 10% will be false positives?

{added: great answers below} well worth understanding this point. In short
specificity measures the % of the population tested which had false positives,
but doesn't give you the ratio of false positives to positives or the
probability that a positive test means you actually have the anti-bodies.

~~~
gwd
Let me give it a try. Suppose we have 100,000 people in a statistically
representative town.

If 1% of people have had COVID-19, then that's 1000 people who have had it,
and 99,000 people who haven't.

The test has a sensitivity of 100%, which means all 1000 people who've had it
will test positive.

The test has a specificity of 99.9%, which means 98,901 of the 99,000 people
who haven't had it will test negative; but that leaves 99 people who haven't
had it, but test positive anyway.

That gives us 1099 people who look like they have immunity; but only 91% of
those people are actually immune: 9% of the people are false positives.

If instead we have a specificity of 99%, then only 98,010 of the 99,000 people
who haven't had it will test negative, leaving 990 people who haven't had it
but test positive anyway.

That gives us 1990 people who look like they have immunity; but only 50% of
them actually do -- the other 50% are false positives.

~~~
InvaderFizz
So if I'm understanding this correctly, with this test.

If you test negative, you are clear, guaranteed, no false negatives.

If you test positive, there is a 10% chance it's a false positive.

I guess my follow up question, does a retest of the positive population make
that false positive rate drop to 0.1%, or is the reason for false positive
significant to an individual and not random chance?

~~~
gwd
> If you test positive, there is a 10% chance it's a false positive.

Well, don't misunderstand -- it's got nothing to do with the test per se, but
with the probability that you had the disease in the first place.

The test itself has two probabilities:

1\. If you've had COVID-19, the probability that it will report positive
(sensitivity)

2\. If you haven't had COVID-19, the probability that it will report negative
(selectivity)

But those probabilities give you a mapping from reality -> test_result. What
you want is the reverse of that -- and find the probability from a test_result
-> reality. When you do that, you have to factor in the probability that you
have the disease in the first place.

If 50% of the population have had COVID-19, then a positive test means a 99.9%
probability of having had the virus. If 1% of the population, a positive test
means 91% likely you have it. If only 1 in a million people had COVID-19, then
the number of false positives would completely overwhelm the number of true
positives.

This is sometimes called the "Base rate fallacy": forgetting to factor in the
base rate when determining something like this.

It's important for things like, say, systems which automatically detect
terrorists at airports. How many travelers at an airport are actually
terrorists planning to attack a plane? It's got to be one in hundreds of
millions, if not billions. With that low of a base rate, even if you had a
system that was 99.999% accurate, the vast majority of people it flagged up
would be innocent.

------
danans
It seems like a voluntary test for someone without symptoms is of limited
value to the individual (beyond their individual curiosity) since we don't
know enough either way about reinfection risk at this point, and the result is
not terribly actionable - you can't just walk into stores without a mask
because you have a positive antibody test - nobody is going to trust your lab
result printout as a reason to avoid public health measures.

But that said, there should be a public health benefit to broad antibody
testing to understand the true infection rate, and for that reason alone,
seems like tests like this should be covered by insurance or the public purse
for everyone - at least in areas with outbreaks or at high risk for outbreaks.

~~~
adrr
People hav held off seeing their parents. If I knew i had antibodies, I’d plan
a trip later in the summer to live with them and do all the shopping to
decrease the risk of them getting infected.

People with antibodies are the best people to provide services with the at
risk population.

~~~
sambe
Parent comment: “we don't know enough either way about reinfection risk at
this point”

Are you disagreeing or did you miss that?

~~~
Marsymars
I think it's pretty a pretty safe guess that given what we know about viruses
work, someone who's already been infected travelling to live with parents and
do their shopping for them will lead to a net decrease in infection risk.

------
m4rtink
Cool, it's nice to see progress on antibody tests - the early Chinese ones in
use here in Czech Republic are reportedly (accordingly to local news articles)
rather noisy. Still preaty nice when they work, as you only need a drop of
blood & get results in 10 minutes vs sample swabbing & complicated PCR sample
processing taking up to a day.

~~~
mlyle
A bigger issue than the specificity of the antibody tests is that they're
generally not positive until you're nearly recovered. This confines their use
to specific purposes (assessing whether someone may be immune, estimating true
infection fatality rates, etc).

------
Ladyady
If you live in the UK, you can get Abbott's test from Forth:
[https://www.southwalesargus.co.uk/news/18441478.first-to-
mar...](https://www.southwalesargus.co.uk/news/18441478.first-to-market-
covid-19-antibody-testing-kit-98-accuracy-launched-chepstow-firm/)

~~~
DoingIsLearning
> All kits can be purchased online with the samples taken in the home or
> workplace, before being sent away for analysis.

Is this possible for other EU countries or is the lab analysis/transport
limited to UK only?

~~~
Ladyady
On Forth's FAQ it says: "Our service is available within the UK only, if you
live outside this territory you will not be able to buy this test."

------
aazaa
The authors don't list an affiliation with Abbott. Usually such a paper will
have a statement about conflict of interest or competing interest. This paper
has none that I can find.

------
dooglius
Caveat from the discussion:

> It is unclear what the prevalence of antibody is in individuals with
> subclinical or asymptomatic infections and how this assay performs in an
> asymptomatic population.

------
guscost
> Our serological validation was chiefly limited by use of excess serum
> specimens from a mostly hospitalized population known to be very recently
> infected with SARS-CoV-2.

Basically, this test may not be as sensitive (or patients may not seroconvert
as often) with mild or asymptomatic cases. To avoid this problem we should run
a two-part study, the first part a PCR test of a large _random_ sample, and
the second part a follow-up to measure antibodies. Has anyone heard about a
study of this kind that may be in progress?

------
jariel
'Specificity and Sensitivity' are new words that are now going to enter the
public consciousness with regards to testing.

Before Iraq War 2, in 2003, absolutely nobody knew the difference between a
'Shia' or 'Sunni' Muslim, and then it became more common knowledge.

It's neat to see how these events shape awareness.

Now every time a Nurse does a test, people will ask "What's the specificity?!"
which can be a good or bad thing.

~~~
s1t5
Specificity and sensitivity feel really poorly chosen and difficult to
remember. You could swap their definitions and the names of the terms would
make just as much sense. I much prefer true positive rate and true negative
rate.

~~~
vikramkr
Those named could be confusing to. True positive rate = .95 could be
interpreted as, if you get a positive result, that's a 5% chance of a false
positive, when the percent chance of the test being a false positive given a
positive result is actually a function of the true positive percentage in the
population and not innate to the test.

~~~
s1t5
That kind of confusion has nothing to do with the terms though, it just
requires a deeper understanding of the process and the statistics around it.

------
tptacek
These stats are generated just a couple weeks after symptoms or PCR test
positivity. I'm still wondering how specificity might drop off for much
earlier exposures. Anecdotally: people on my Fb feed are getting positive
tests they attribute to illnesses they had back in January and February.

(This concern has nothing to do with the benefit these tests have in "real
time" testing).

~~~
ridgeguy
Your FB feed results don't seem impossible. First CV-19 death in CA was Feb 6
[1]. That's presumably at least a couple of weeks after infection.

[1] [https://www.nytimes.com/2020/04/22/us/coronavirus-first-
unit...](https://www.nytimes.com/2020/04/22/us/coronavirus-first-united-
states-death.html)

~~~
tptacek
The question isn't whether they're possible, it's whether the antibody tests
are reliable that far from the actual incidence of C19.

~~~
guscost
Don’t you mean _sensitivity_ dropping off? The way it’s phrased sounds like
someone is more likely to get a false _positive_ as time passes after... no
infection happened?

------
xoxoy
Do these tests measure level of antibodies? Unclear still what correlation is
between level and strength of immunity

------
vipa123
Does anyone know what these tests cost?

~~~
dhd415
In the US, they're $119 through Quest Diagnostics. In some areas and with some
insurance companies, that cost is fully covered.

~~~
cypherpunks01
Do you know that all the Quest tests are mfg. by Abbott? I didn't see that
anywhere, they didn't seem to show which test manufacturer you got when you
receive results either.

~~~
dhd415
The Abbott test may not be used everywhere. I've called them to confirm their
labs local to me use the Abbott test and that's probably what you should do if
you're looking to get this test. While it does not guarantee that they use the
Abbott test in every region, you can see that they reference Abbott in the
footnotes for question #3 in their FAQ on COVID-19 testing here:
[https://education.questdiagnostics.com/faq/FAQ219](https://education.questdiagnostics.com/faq/FAQ219)

------
blackrock
Nice! Last year, in July 2019, in Virginia, there were a bunch of strange flu
like illnesses, leading to pneumonia, and deaths [1]. When will these people
get tested for the antibodies?

[1] [https://abcnews.go.com/US/respiratory-outbreak-
investigated-...](https://abcnews.go.com/US/respiratory-outbreak-investigated-
retirement-community-54-residents-fall/story?id=64275865)

------
SethTro
Slightly misleading headline. The test is not new, it's been launched since
April and has already shipped 10M tests.

According to [https://abbott.mediaroom.com/2020-05-08-Research-from-
Univer...](https://abbott.mediaroom.com/2020-05-08-Research-from-University-
of-Washington-Demonstrates-High-Performance-of-Abbotts-SARS-CoV-2-Antibody-
Blood-Test)

~~~
3001
It's new.This is the second antibody test Abbott is launching.

Disclosure: I work for Abbott.

~~~
rindalir
Do you know which of the two is being used by commercial labs like Quest now?

------
londons_explore
How can one measure such high sensitivity and specificity rates when no other
test has such high rates?

Surely the only way to measure a test is to compare against ground truth data,
which can only come from other test processes, and therefore can never reach
100%?

------
elil17
The Quest website warns that having the antibodies does not necessarily mean
you are immune. Is it really likely that reinfection is possible less than a
year after initial infection, or is that just something they have to write as
a disclaimer?

~~~
vikramkr
We just don't know right now. Some antibodies could work better than others,
so for some people it could mean yes and for others no. Could be different for
symptomatic vs asymptomatic patients. Some antibodies could make the disease
worse through ADE. Immunity is probably conferred for at least a couple months
since we dont see a huge number of reinfection, but we dont know whether it
trails off after a year or two or goes below an important concentration
threshold since there physically hasn't been enough time since the start to
measure immunity out to a couple years. In general, you're probably fine, but
maybe not, and the test could also be giving you a false positive.

------
evan_
Great, now please make 100 billion and send a package to every household in
the world.

~~~
mh-
I believe these require a blood draw.

~~~
evan_
People who have diabetes often do blood tests daily, at home, on their own,
drawing a drop of blood from their finger with a lancet. If they can get it
down to using a drop of blood, I think people could be convinced to test at
least one member of the household daily. That should at least give us enough
information to measure spread.

It would be new for most people but it's not unprecedented and I think people
would figure it out quickly enough. Conspiracy theorists would ruin it for
everyone of course.

~~~
aeonsky
I'm sure you are aware of story behind Theranos - doing complex tests on a
drop of blood is currently impossible.

~~~
adatavizguy
Would there have been a path of honesty at Theranos such that they would
thrive in the age of covid-19?

~~~
whatshisface
That's like asking, "could Enron have been an honest energy company..." sure,
with a different board, different executives, different strategy, different
technology, different IP, different market sector, and if they sold ice cream
cones for fair prices at the local pool.

------
mvkel
I know everyone is saying that getting reinfected with covid isn’t technically
ruled out, but is it safe to assume so? It seems very difficult to find a case
of someone truly being reinfected.

------
mcguire
Has anyone reported doing the sampling to determine the prevalence?

------
whatshisface
> _Alternative index value thresholds for positivity resulted in 100%
> sensitivity and 100% specificity in this cohort._

This would be true of a coin flip, wouldn't it? "Head means positive, tails
means not negative" would be 100% sensitivity and "Tails means negative, heads
means you're not positive" would be 100% specificity. So those would be the
"alternative index value thresholds."

[https://en.wikipedia.org/wiki/Sensitivity_and_specificity](https://en.wikipedia.org/wiki/Sensitivity_and_specificity)

~~~
trehalose
You misunderstand. A test that labels everyone positive would be 100%
sensitivity but 0% specificity, and a test that labels everyone negative would
be 100% specificity but 0% sensitivity. Deciding every case at once by a
single coin flip would thus be useless.

As the article says, "A perfect predictor would be described as 100%
sensitive, meaning all sick individuals are correctly identified as sick, and
100% specific, meaning no healthy individuals are incorrectly identified as
sick." Deciding every case at once with a single coin flip does not meet both
critera of a perfect predictor.

~~~
whatshisface
Not at the same time, but it does if you split it in to two separate tests,
each with an "Alternative index value threshold."

------
platz
which is more accurate, a Laboratory-based immunoassays using using serum or
RDT blood samples from a finger stick?

------
ck2
and for "only" $120 you too can buy it (priced for insurance to pay out but of
course many millions don't have insurance/anymore)

[https://questdirect.questdiagnostics.com/products/covid-19-i...](https://questdirect.questdiagnostics.com/products/covid-19-immune-
response/b580e541-78a5-48a6-b17b-7bad949dcb57)

(quest uses the Abbott igg)

------
bb88
As someone who lives in Boise, I'm angry:

1\. People had to buy this test. It wasn't free.

That means

2\. whoever bought the test were guinea pigs in this study.

And

3\. That fact wasn't being made clear in Crush the Curve.

LabCorp should refund all the tests in Boise immediately.

~~~
vikramkr
Nobody paid to be a part of this clinical trial. That's highly unethical.
People were paying for a different test.

------
Animats
This is encouraging. Two negative viral tests and a positive antibody test,
and people should be able to get an ID that says they're exempt from movement
and mask restrictions. (To discourage faking this, getting that ID should also
turn eligibility for the Emergency Care Benefit, since they can work safely.)

There's still argument over how long immunity lasts, but it has to be at least
two or three months, or there would already be widespread (large numbers)
reports of people getting the disease more than once. So, for now, IDs could
be good for three months. They can be extended later as more info comes in.

First step in the US should be to test first responders in NYC. NYC already
has maybe 21% antibody-positive people, and those on the front lines are
probably higher. Knowing who's immune will be a great relief to them.

~~~
feyman_r
>>> ..they're exempt from movement and mask restrictions ...

There's a negative repercussion of people around such folks getting a false-
impression that masks are not a serious need (if this is in question, that's a
different discussion). It also creates a possibility of visible 'haves' and
'have-nots', which can cause trouble.

I think having uniform messaging for movement/masks irrespective of antibody
presence will remove variability in response from people.

~~~
Animats
So the ID card goes on a lanyard.

 _It also creates a possibility of visible 'haves' and 'have-nots', which can
cause trouble._

Yes. So? Gradually, more people are added, painfully, to the "have' list.

