About 83 percent of blood donors had infection-induced or vaccine-induced COVID-19 antibodies by May 2021, according to research published Sept. 2 in JAMA Network.
The study involved more than 1.4 million blood donation specimens from all 50 states, representing a catchment of 74 percent of the U.S. population.
Antibodies induced from a COVID-19 infection rose from about 3.5 percent of donors in July 2020 to 20.2 percent in May 2021. The combined infection and vaccine-induced seroprevalence estimate by May 2021 was 83.3 percent, findings showed.
Researchers observed differences in the source of antibodies among racial groups. Infection-induced antibodies were consistently highest among Hispanic and Black donors, the findings said.
"However, by May 2021, non-Hispanic Asian and White persons had significantly higher combined seroprevalence estimates, likely because non-Hispanic Asian and White persons received vaccinations at a greater rate than Hispanic and non-Hispanic Black persons," researchers said.
The study will continue through at least December, with results to be shared on the CDC's website.