New lit review post, this one on #COVID19 antibody testing. srconstantin.github.io/2020/04/27/ant…
tl;dr:
you know those new antibody test results saying way more people have asymptomatic virus than was thought possible, and thus we don't have to worry about it because it's low risk?
you know those new antibody test results saying way more people have asymptomatic virus than was thought possible, and thus we don't have to worry about it because it's low risk?
Yeah nope.
Even the *optimistic* assumptions projected from those antibody studies suggest that the US would have a per-capita death rate comparable to the Spanish Flu if we let it go completely unchecked. Not good.
Even the *optimistic* assumptions projected from those antibody studies suggest that the US would have a per-capita death rate comparable to the Spanish Flu if we let it go completely unchecked. Not good.
Also, you know how the CDC said there was "no evidence" that antibodies against COVID-19 would protect you against reinfection?
Also nope.
There's no evidence *in COVID-19*, but I found very consistent evidence across 6 different viruses, including a coronavirus, that higher virus-specific antibody levels predict lower risk of symptomatic infection with that virus.
There's no evidence *in COVID-19*, but I found very consistent evidence across 6 different viruses, including a coronavirus, that higher virus-specific antibody levels predict lower risk of symptomatic infection with that virus.
*the WHO, sorry.
There are virus studies in which a *detectable* antibody titer can still precede symptomatic (re)infection, so I wouldn't go around assuming that a positive test result on one of those yes/no drive-thru tests means you literally can't get COVID19.
But is, for instance, antibody response a plausible initial proxy for testing whether a vaccine candidate is protective against COVID19? Yeah, probably. It's a standard endpoint in the development of other viral vaccines.
Also, it depends what the antibody tests are being used for.
As a population measure of how many people have been infected with COVID-19? They're good, PLEASE DO MOAR ANTIBODY TESTS.
As a population measure of how many people have been infected with COVID-19? They're good, PLEASE DO MOAR ANTIBODY TESTS.
As a guide to clinical treatment of individual patients?
Probably not great, since they'll show up negative even in infected patients for the first two weeks after symptom onset.
Probably not great, since they'll show up negative even in infected patients for the first two weeks after symptom onset.
As a guide to identifying who needs to be quarantined?
Again, not ideal, because they'll miss newly infected patients (who are at their most contagious) but maybe better than nothing.
Again, not ideal, because they'll miss newly infected patients (who are at their most contagious) but maybe better than nothing.
My general heuristic of "don't trust claims by known COVID-19 Pollyannas" seems pretty vindicated by the facts here.
