Bloomberg – Covid-19 vaccines from Pfizer Inc. and Moderna Inc. effectively prevented coronavirus infections, not just illness, with substantial protection evident two weeks after the first dose, government researchers said.
Two doses of the vaccines provide as much as 90 percent protection against infection, according to data from U.S. Centers for Disease Control and Prevention study published Monday. Earlier clinical trials had established that the shots also prevent illness, hospitalizations, and deaths.
The study adds to evidence that new vaccines made with messenger RNA technology actually reduce the spread of the virus in real-world conditions. An earlier study in Israel found a single dose of the Pfizer vaccine reduced infections by as much as 85 percent.
The CDC studied a group of about 4,000 front-line workers, including health-care personnel, first responders, teachers and service workers from mid-December to mid-March as vaccines rolled out widely. These groups were among the first to be vaccinated, along with the vulnerable elderly, because of their risk of exposure to the virus.