A new study found strong evidence mRNA COVID-19 vaccines were highly effective in preventing infections among healthcare personnel and other essential workers.
The analysis, released Monday by the Centers for Disease Control and Prevention (CDC), looked at the effectiveness of the Pfizer-BioNTech and Moderna vaccines that use the mRNA technology.
“Results showed that following the second dose of vaccine (the recommended number of doses), risk of infection was reduced by 90% two or more weeks after vaccinations,” the CDC said in a release.
The risk of infection after a single dose was reduced by 80% about two or more weeks after getting the shot.
“This study shows that our national vaccination efforts are working,” CDC Director Rochelle Walensky, M.D., said in a statement. “The authorized vaccines are the key tool that will help bring an end to this devastating pandemic.”
Front-line healthcare workers were among the first to get vaccinated after the vaccines were approved last fall.
The study had 3,950 study participants across six states and took place between Dec. 13 and March 13.
“Researchers were able to look for evidence of [COVID-19] infection irrespective of symptoms,” the CDC said. “A small number (10.7%) of infections in this study were asymptomatic (i.e., did not result in symptoms).”
A majority of the infections (58%) occurred among people whose cases were identified before developing symptoms or knowing they were infected.
“The study demonstrates that these two mRNA vaccines can reduce the risk of all SARS-CoV-2 infections, not just symptomatic infections,” the CDC added.
The study comes as the CDC is worried about an increase in cases in recent weeks.
Walensky warned of “impending doom” during a White House briefing Monday. She pointed out the seven-day average of cases was slightly less than 60,000, a 10% increase compared to the prior seven-day period.
“We have so much to look forward to and so much reason for hope but right now I am scared,” Walensky said.