CDC Director Rochelle Walensky said the study shows national vaccination efforts are working. “What we really want to do is test these vaccines in the real world, to see how well they work,” said Gandhi, who was not involved in the CDC study. The clinical trials had large numbers of older people, but the CDC study focused more on working-age adults and the ability of the vaccines to protect against infection, regardless of whether symptoms developed. About 63 percent of participants received the Pfizer-BioNTech vaccine and 30 percent received the Moderna shot. ADThe study did not provide an estimate of the vaccines’ benefits against the virus variants circulating in the United States.

Source: Washington Post March 29, 2021 15:00 UTC