Re: 2019 Coronavirus (COVID-19)
The point I'm asking is if we don't know then how long it takes to seroconvert, then all of this publicity about getting millions of people tested and the test-me-now mentality of many folks, may in fact be pointless if your test shows negative? True? For an accurate result and reassurance that you're actually negative you'd have to be tested over and over many times and then you could pick up the virus on the way home. This sounds like a circle. The test is really only useful if you're showing symptoms or if you know for sure you've been exposed and even then you have to repeat it multiple times, it sounds like.
So, there's two types of testing- antibody (seroconversion) and antigen (which looks for RNA or some part of the virus/bacteria).
At this moment,
we have no antibody test for COVID-19, so we aren't doing blood or serum testing looking for a antibodies (which would tell us if you
ever had COVID-19)..
Most of the tests that US has done for COVID-19 are
antigen tests... specifically PCR testing. PCR takes a small amount of the virus from a throat or nasal swab, clones it repeatedly in a machine and
then runs an antigen test. That's why it's taking 1-3 days to get results, because a PCR test has to be run in a specialized lab.
Where we want to get to is a point of care test which looks for tiny amount of antigen and produces an immediate "positive" or "negative"- similar to a home pregnancy test.
Re: purposes of testing... We test for two reasons:
- For individual treatment: To know what we're treating and what we need to do for the patient.
- For community surveillance: so that we know how many people are sick and how many people are carriers
The US was able to get by without COVID-19 testing for reason #1 because regardless of whether you have a cold, the flu or coronavirus- the prescription is pretty much the same- rest, isolation, good nutrition/hydration and over the counter medications. And we were lucky because the majority of people >50% don't get deathly ill from coronavirus. Even if you are one of the unlucky people who gets severe illness from COVID-19, we don't have a drug or any specific treatment that we can give you.
Testing has become a big issue for reason #2 because we've come to realize that there is a large group of people who feel well but are shedding the virus from their nose and throat. They are infecting people en masse, whether those people are healthy people who will create more cases or whether it is unhealthy people who end up in our emergency rooms (or morgues) with severe illness.
We need people tested at this point because we need to get those people with the virus out of public spaces until they are no longer contagious. And because we have no treatment for the virus, those people could be at home in isolation for up to 2 weeks.
We are a bit hamstrung at the moment, because we have no mass testing capacity in the US and the current antigen testing is taking days to get results. We expect this to change as new tests become available and we may be able to get to a point where results are available in a few hours.
It will take a few weeks or months for the "point of care" tests to be available, then we will get new tests that give us immediate results so we can swab your nose and say, "You have the virus" immediately.
