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, USA government researchers said.
Two doses of the vaccines provide as much as 90% 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%.
The study is “tremendously encouraging” CDC Director Rochelle Walensky said in a briefing, and new findings “underscore the importance of getting both of the recommended doses of the vaccine in order to get the greatest level of protection against COVID-19, especially as our concerns about variants escalate.”
While the research bodes well for halting the spread of the virus and speeding economic recovery, health officials remain concerned. Cases, hospitalizations, and deaths are rising again in the U.S., and the CDC’s head cautioned that a new surge is building with much of the country still susceptible.