For your situation, existing antibody tests are fine. They are not accurate enough to do mass testing to find out how prevalent SARS2 is in the population. This is because the base rate in the population is pretty low. If you are reasonably sure that you've had it, a false negative/false positive for you is still pretty unlikely (in the 5% order of magnitude range for lateral flow antibody tests, better for ELISA lab tests).
A positive test result for antibodies is a strong indicator for having been exposed to covid, but a negative test result doesn't say much because 80% of people exposed to covid don't produce antibodies, even if they get sick and recover. It doesn't matter how good the test is if seropositivity is the exception rather than the rule.
> because 80% of people exposed to covid don't produce antibodies
Are there any data available to support this claim? That would mean that the virus is cleared by the innate immune system and not the adaptive, but it is still a pretty bold statement.
The last I read (a Nature Genetics study, if I recall) was that the antibody quantity was lower in milder cases (but with a large inter-person variability).
Yes, I linked to a relevant paper in this thread. (And I think it's what you would expect for a disease that is non-symptomatic for many young/healthy people.)
> That would mean that the virus is cleared by the innate immune system and not the adaptive
Not necessarily, because adaptive antibodies produced through previous exposure to coronaviruses can also bind to covid19.
> Nevertheless, rare but recurring RBD-specific antibodies with potent antiviral activity were found in all individuals tested, suggesting that a vaccine designed to elicit such antibodies could be broadly effective.
Very low levels, but still produced. (Note that I still have to dig through the paper.)
My understanding is that those RBD-specific antibodies are not necessarily produced as a response to covid19, but I could be mistaken.
In addition:
> Plasmas collected an average of 39 days after the onset of symptoms had variable half-maximal neutralizing titers ranging from undetectable in 33% to below 1:1000 in 79%
Of course this is only a single study and more research is needed, but I notice people draw way too strong conclusions from studies that show low seropositivity prevalence.
That was exactly my point (and a reason why getting an antibody test is still useful in the context of a single person). Thanks for explaining it better than I did.
