A study published by the federal Centers for Disease Control and Prevention (CDC) showed that mRNA vaccines from Pfizer-BioNTech and Moderna are highly effective in preventing COVID-19 “in the real world.”
The study, which took place from December 14 to March 13 in six states, was attended by about 4 thousand medical, emergency workers and other workers performing functions of primary importance.
The results showed that the risk of infection was reduced by 80 percent after one dose and by 90 percent after two doses.
Speaking at a White House COVID-19 response briefing, CDC Director Rochelle Walenski said the vaccines could be effective for not only symptomatic infections, but also asymptomatic cases.
She called the findings “extremely encouraging,” noting that they complement other recent studies published in the New England Journal of Medicine and elsewhere.