Pfizer-BioNTech and Moderna vaccines against coronavirus are 94% effective in preventing symptoms of Covid-19 disease, according to a new study of more than 1,800 healthcare workers in the United States.
The research, published by the CDC last Friday, provides more evidence that vaccines work well even outside of controlled clinical trials.
“This report provided the most compelling information yet that Covid-19 vaccines are working as expected in the real world,” said Dr. Rochelle Wallinski, Director of the CDC.
“This study, added to many of the studies that preceded it, was helpful in changing the CDC’s recommendations for those who have been fully vaccinated against Covid-19.”
The results are based on an ongoing study of healthcare workers in 25 states. This interim analysis included data on 1,843 healthcare workers who underwent routine tests for coronavirus infection. More than 80 percent of the participants were women.
623 workers tested positive between January and mid-March. The researchers found that those who were fully vaccinated were 94 percent less likely to develop symptoms of a coronavirus infection compared to their unvaccinated peers. The numbers are consistent with estimates of effectiveness from clinical trials.
Scientists also found that a single dose of the dual injection system was 82 percent effective in preventing symptomatic infections. This number is higher than what has been reported in other studies and may be a result of the relatively young population of study participants, between the ages of 37 and 38. Less than 2 percent were 65 years of age or older.
Scientists previously found that primary frontline healthcare workers who were fully vaccinated were 90% less likely to contract the coronavirus. These results helped allay fears that vaccinated people could carry the virus, even asymptomatically, and pass it on to others.
Anxiety was one of the main reasons for requiring vaccinated Americans to continue wearing face masks, a recommendation the CDC made last Thursday.