Who should get a COVID-19 test (in mid-May, in Massachusetts)?
May 9, 2020 6:27 AM   Subscribe

My city (a close-in Boston suburb) is offering COVID-19 tests (viral, not antibody) to all residents, regardless of symptoms. I have no symptoms and probably lower-than-average risk of exposure but I'm considering getting tested. In a perfect-except-for-coronavirus world, who would be getting tested, and how often?

Presumably if my city Board of Health is offering these tests, they want residents to be taking them - our infection rate is pretty high. That said, I am probably at low risk of exposure relative to the average resident of my city. We're two-person household with no one working outside the home; I go out to buy food about once a week and take my spouse to medical appointments about every other week. Our city has a substantial working-class and immigrant population who are living/working in more dangerous conditions. Some of our neighboring cities/towns have even much higher rates of infection but we live on the other side of town from those communities and don't do our shopping there.

If I call and I'm able to get an appointment right away I guess I won't worry about it but if there's a backlog I'm not sure whether *I* ought to be getting tested. Is this the kind of broad testing that needs to happen to get positive test rates down to a manageable level, or should I skip getting tested for now and leave my slot and swab available for my higher-risk neighbors who are living in more crowded households and/or working outside their homes? I have basically zero concern that I'm actually infected, though of course if I'm infected and asymptomatic that would be really important to know. My husband tested negative about a month ago and has had no COVID-19 symptoms and minimal opportunities for exposure since - would it make sense for him to be tested?

Personal considerations aside, I'm mostly curious about what an optimal testing strategy (in the absence of test shortages) looks like, and given that the availability and accessibility of tests has changed so much over the past couple of months it's hard to get a straight answer about this. Articles, tweet-threads, etc. are all welcome on this topic!
posted by mskyle to Health & Fitness (20 answers total) 4 users marked this as a favorite
 
I would not get tested unless I was exhibiting symptoms or had come into contact with someone who had tested positive. I don't see the point in getting tested without those criteria because a negative test would not change the way I behave. When I go outside my house, I act as if I have Schrodinger's COVID - I am both asymptomatic and someone who can catch it.

Say you get the test and you are negative. That's great. Do you plan to keep getting the test every week or every other week to make sure you haven't gotten infected since your last test?
posted by Constance Mirabella at 7:31 AM on May 9, 2020 [10 favorites]


You should absolutely get tested. Many people are asymptomatic. It is important to understand how many people have been infected. If we only ever test those who exhibit symptoms, we will not understand how widespread the virus actually is.
posted by King Bee at 7:36 AM on May 9, 2020 [4 favorites]


It is important to understand how many people have been infected.

Yes it is, but it is important to note that the viral test (which is available to mskyle) only indicates current infection. To identify past infection, you need an antibody test (which is not available to mskyle via their city's program).

We need everyone to take the antibody test - that's how we understand who is still at risk, and who is no longer at risk, and is likely critical to reopening the economy. But taking the viral test absent of a reason to believe the person might be infected (symptoms, exposure, etc.) doesn't provide much insight or value.
posted by NotMyselfRightNow at 7:54 AM on May 9, 2020 [4 favorites]


I hate to threadsit, but I have seen the statement that ideally we shouldn't return to normal-ish until the positive test rate for the viral test is below 3% - presumably to achieve this test rate we would need to test a lot of people who do not have symptoms (though maybe that test pool should consist of people with a somewhat higher risk of exposure than me).

The antibody test on its own would surely be insufficient to indicate whether it is safe to reopen (unless we're already at the herd immunity stage), since it only tells you who has had the virus, not how many cases are currently circulating. If 30% of the population has the antibody and none of them has the virus, you're grand; if 30% of the population has the antibody and 15% of them have the virus you're a mess.

I'm assuming the main benefit of me (and people like me) getting tested would be at the public health level, not anything to do with my personal life. The most likely case would be that I would test negative and I would not change my behavior; I would of course have to quarantine if I tested positive, but that seems very unlikely.

If I got the antibody test I would not change my behavior either way - false positive rate on those seems to be still too high to be useful at the individual level, though again it is probably useful for public health purposes. I think right now I can only get the antibody test if I've had symptoms, though, so it's moot.
posted by mskyle at 8:16 AM on May 9, 2020 [1 favorite]


But taking the viral test absent of a reason to believe the person might be infected (symptoms, exposure, etc.) doesn't provide much insight or value.

The reason to believe the person might be infected is because we are all sheltering in place because of this virus. The R0 for the virus is quite high. It is easily transmissible. We should act as though we are all carriers because of the long incubation period. We're supposed to act as though we're carriers of the virus, but don't get tested for it? That makes no sense.

You should get tested if you have an opportunity to do so.
posted by King Bee at 8:26 AM on May 9, 2020


The answer to the question (who should be tested?) depends on who you are asking. An epidemiologist would want everyone tested every day do he could get the best possible data. Your local doctor only needs a test if you have symptoms. Your Mayor wants you to have a test if you think you might have been exposed.

So you can feel free to take someone else's criteria or develop you own. The higher the percieved risk to yourself or others, the higher your motivation to get tested. Or, you might think it's a civic duty. But it is your call.
posted by SemiSalt at 9:23 AM on May 9, 2020


In a more perfect world where there was a competent national response, we would have already massively scaled up testing and contact tracing. If enough people are getting tested frequently enough, you can then spot outbreaks as they occur and isolate just those, rather than having most of the population sitting around. (You also want widespread antibody testing to understand who has already had the infection, but that's in addition to testing for the active disease, not instead of it.)

So yes, follow local and state guidance as they ramp up testing, especially as they are switching from focusing on high risk people to the general populace, and get tested when you legitimately meet the criteria. Where I live, because of limited capacity testing is still focused on high-risk groups (eg health care workers) and people with symptoms or known exposure, but as the capacity increases that focus will shift.
posted by Dip Flash at 9:34 AM on May 9, 2020


We should act as though we are all carriers because of the long incubation period. We're supposed to act as though we're carriers of the virus, but don't get tested for it?

If you took the viral test today and it came back negative, what would you do with that information?

If you take a viral test, you learn the answer to one question: Am I sick at this very moment?

If the answer is yes, you're not going to do anything differently. You're going to stay home, avoid people, wear a mask, etc. because you know you could infect someone else.

If the answer is no, you're still not going to do anything differently. You're going to stay home, avoid people, wear a mask, etc. because you must assume you could get infected then infect someone else.

The antibody test (telling you if you had the illness in the past, and are immune to getting it again) and the viral test after a diagnosed case (telling you if you have healed) result in you gaining insight that could lead to a change in your personal circumstances or behavior.

(This isn't a criticism of the viral test, to be clear. It's beneficial for providing care to ill people, and to protect those helping them. My spouse is an essential worker, and just had to go get one earlier this week because of a possible exposure at work. I'm happy we live somewhere where that was easily and quickly available, as were the results.)

The antibody test on its own would surely be insufficient to indicate whether it is safe to reopen (unless we're already at the herd immunity stage), since it only tells you who has had the virus, not how many cases are currently circulating. If 30% of the population has the antibody and none of them has the virus, you're grand; if 30% of the population has the antibody and 15% of them have the virus you're a mess.

If a small business with 20 employees is closed because it can't be open and have safe distancing between employees or other similar precautions, and we then know that 15 of those employees have antibodies, those 15 could potential go back to work and restart the business while the remaining 5 stay home and stay safe until a vaccine is available.
posted by NotMyselfRightNow at 9:52 AM on May 9, 2020


The antibody tests currently available absolutely cannot give us that level of certainty at an individual level. What COVID-19 Antibody Tests Can and Cannot Tell Us.
posted by mskyle at 10:14 AM on May 9, 2020 [7 favorites]


I took both tests, the viral one and the antibody one. (Not at the same time.) I was negative for both. In hindsight, I would not take either of them again unless I was so sick I required hospitalization. I learned nothing. I learned I was not sick at the moment I took the test and I learned a month or so later I never was sick with C19. I did nothing different before or after the test. I think if I had a positive result from the antibody test, I would still be masking and bobbing and weaving. Unless you can tell me for a fact that having the antibodies is absolute immunity from getting it again, I would still be the same level of diligent. To me, the tests only help a small segment of the population and tells the government something that will be twisted for their benefit whatever that may be at the time.

To me, the important thing is to be preventative for your own health and protect those around you by wearing a mask and social distancing. THat leads us back to everyone wearing masks and social distancing regardless of how they test.
posted by AugustWest at 10:15 AM on May 9, 2020 [2 favorites]


No. If you are not working, sheltered at home, and have no symptoms, you should not be taking a virus test while healthcare workers, patients, essential workers, nursing home residents and staff, and etc etc etc need them so desperately. We are slowly coming out of the shadow of ‘not enough tests’ but we are not there yet.
They’re offering free antibody tests walking distance from me. I am also not working, sheltered at home, etc. I’m going to wait a month until the people who are working out there day after day get a chance first. Imagine what it’s like out there, for them. Wait.
As far as ‘how long?’... I would say about a month. My predictions on this have been pretty good. I predicted in march that virus tests would be available in april, and they were, and in april I thought we’d have AB tests in a month, and they’re available now. (My definition of ‘available’ has been ‘could I get a test if I lied.’ Like “overseas travel? Well, as a matter of fact I was licking doorknobs in Wuhan before going to the big game in Italy” ...i.e. ‘are tests physically available in the area.’) I expect to see the situation here (AB tests for all residents, free, no doctor referral necessary) available in many more, if not most, places in the US by the end of the month. Unless of course the ‘open everything immediately’ boneheads don’t make the whole thing much much worse, in which case those test kits will be even more vital for hospital use.
posted by sexyrobot at 10:30 AM on May 9, 2020 [2 favorites]


Oh, and Rosche (IIRC) has a new AB test that’s actually accurate... my doctor friend was telling me about it. I think I heard (prob on pbs newshour) that they got actual FDA approval (not just ‘emergency use’ approval) in the last few days.
posted by sexyrobot at 10:43 AM on May 9, 2020


If it's personal advice you want, honestly, I'd call your Board of Health and ask. I think this is one of those situations where local knowledge is essential if you want advice that's actually appropriate for your situation.

For articles, here's a recent one that addresses testing. On Twitter the person I follow who has been talking about it the most is @JeremyKonyndyk.
posted by eirias at 10:48 AM on May 9, 2020


The antibody tests currently available absolutely cannot give us that level of certainty at an individual level.

That's true - but it's also true about the viral test:

"In the real world, testing conditions and process are far from perfect, and accuracy suffers. Researchers still don’t know what the real-world false positive rate is, but clinical sensitivity of RT-PCR tests ranges from 66% to 80%. That means nearly one in three infected people who are tested will receive false negative results."
posted by NotMyselfRightNow at 10:55 AM on May 9, 2020


Don't get tested now. Instead, if you have or can obtain a thermometer, start monitoring your temperature. If you see your temperature rise above your personal baseline with this thermometer (even if it's not at fever level), then think about getting tested.

For reference, my spouse and I have both had COVID, as confirmed via symptoms + an antibody test, but my spouse tested negative for COVID twice, once at the beginning of the illness and once maybe six or seven weeks in. "Is this temperature a degree or two higher than normal?" has been a much better guide as to whether we're actually sick.
posted by yarntheory at 11:09 AM on May 9, 2020 [1 favorite]


Yes, the viral test also has accuracy issues but the big difference is a positive viral test tells people “stay home even more aggressively” (or continue enhanced precautions in a healthcare setting) and a negative viral test tells people “keep isolating” (or “retest” in a healthcare setting where symptoms are present). A positive antibody test is being interpreted by some (my aunt, sigh) as “you’re immune, go about your business normally.” And accuracy issues aside there’s still the open question of whether presence of antibodies indicates immunity. The context of the decisions made as a result of the test is important in any discussion of accuracy.

I already take my temperature every day (monitoring spouse for other reasons, easy enough to check myself at the same time). I think it’s very unlikely I have COVID and I don’t expect to get any actionable information from the test. I’m more curious if there’s a public health benefit to my being tested.

The Board of Health’s line seems to be, “if you want to get tested, come get tested.” I presume they wouldn’t be offering this if frontline workers and healthcare workers weren’t able to access the tests (there are additional locations for these workers), and I presume they see some benefit in widespread testing.
posted by mskyle at 11:17 AM on May 9, 2020


In order for public health departments to have reasonable confidence that the curve is shifting lower and more durably in your location, it is important to have data on what portion of the entire local population tests positive for the virus, that's the PCR test. The antibody test, if accurate, could also be helpful, but when identifying what is happening to the at-risk population the PCR test is more helpful. The antibody test can identify people who were infected and is helpful for different reasons having to do with presumed immunity. Some of these antibody-positive people will have been without symptoms, and positivity will be a surprise. These people, though, will likely not be a risk to others, at least in the short term. Nobody knows how long immunity will last, since this is a new virus.

Only when the positive PCR test rate per 1000 steadily drops will we really have confidence that the infection is truly lessening. Testing only symptomatic people is probably most helpful for the symptomatic people (so they get proper care and can better self-isolate), but is not giving us a yardstick for how the community as a whole is progressing.

Public health NEEDS the broader testing of the community to asses the overall progression of infection. It also, importantly, identifies asymptomatic infected people, which is very significant as it relates to any housemates. I would suggest you and your partner be tested, at least for the PCR (though quality antibody testing might possibly surprise you as positive and give you reassurance as quarantines are gradually lifted) and that you encourage your asymptomatic friends and neighbors to opt in as well. Testing only symptomatic people is most helpful to those who are symptomatic and their close family/roommates/friends. Community testing is helpful to everyone.
posted by citygirl at 12:47 PM on May 9, 2020 [5 favorites]


Mass. is in the process of ramping up its contact tracing, so if you did turn out to have it, there would be an additional benefit to the test beyond the personal.
posted by joeyh at 1:34 PM on May 9, 2020


Made my appointment! I'll get tested on Wednesday afternoon and should have the results next week. Even though for me, personally, the test can only give bad/inconvenient news at the moment (if I'm infected and asymptomatic it will suck to have to shift from vanilla shelter-at-home to full quarantine!), it seems like widespread testing and contact tracing are a key part of any rational winding-down of the lockdown.
posted by mskyle at 11:03 AM on May 11, 2020 [1 favorite]


My daughter and I both got tested, at different times, mostly because it was clear that the tests were for public health studies, not for us. And they had a questionnaire so that I was confident that they only tested us because they wanted to. It sounds like your health department is even further along, which is awesome.
posted by Margalo Epps at 8:36 PM on May 18, 2020


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