Does the US have definitive numbers of how many unvaccinated people have natural COVID-19 antibodies?
There is no precise tally of how many unvaccinated Americans may carry natural COVID-19 antibodies acquired through exposure to the virus.
The Red Cross has tested 3.3 million unvaccinated blood donors for COVID-19 antibodies. Between June 2020 and March 2021, 7.5% of all those sampled had antibodies present; in the first week of March 2021, the figure was 20%, as the figure has risen over time. Blood donors are not a random sample of unvaccinated Americans, the report notes.
The Centers for Disease Control and Prevention estimates that about one-third of Americans have been infected. Natural immunity is expected to last about eight months after infection, but varies among individuals.
COVID-19 cases are thought to be underreported, and scientists don't know for certain how antibodies protect against variants, but early research looks promising.