State of New York has pulled back completely from the antibody tests due to the tests not being able to accurately show whether the antibodies are from COVID 19 or a previous COVID infection (common cold) or whether the person even has sufficient antibodies to prevent reinfection down the road...
https://www.politico.com/states/new...ts-on-cuomos-hope-of-immunity-testing-1282219
It’s not accurate to say NY has ‘pulled back completely’ from antibody testing, it’s simply the case that they have stepped back from suggesting the antibody test could be useful for ‘guaranteeing’ that any particular *individual* is immune. I think that’s fair and it’s an important distinction. I can’t speak specifically to the NY antibody test (I haven’t reviewed specificity and sensitivity data for the NY test, not even sure if it’s been released), but the NY antibody testing on a *population level* seems to agree with other independent data such as local fatality #’s, so it’s probably pretty accurate and thus useful for assessing how widely the virus has spread in a given population.
Coming back to another point, it is still a good bet that having antibodies against covid 19 does confer at lest some immunity (there is lots of emerging data consistent with this). But there is a leap from saying ‘yeah, we know this specific antibody prevents coronavirus replication in a lab setting’ to using antibody test results to tell an individual ‘yeah, you’re definitely immune and should feel free to go about your life without any restrictions’. So when WHO and NY come out and say ‘there’s no evidence this antibody test will tell you you’re immune’, that just means that they don’t have enough data yet to provide medical advice. It does NOT mean that covid 19 is uniquely resistant to development of immunity (again, all emerging data I’ve seen suggests many/most people who recover will have some significant immunity).