Pfizer and Moderna's COVID-19 vaccines were 94 percent effective at preventing symptomatic COVID-19 in healthcare workers in the CDC's largest study on the vaccines' effectiveness to date, according to interim results released May 14.
Fully vaccinated workers were 94 percent less likely to develop symptomatic COVID-19 and people partially vaccinated were 82 percent less likely.
The study's sample size covered a broader geographic area than the vaccines' clinical trials, providing further evidence of their effectiveness, according to The Hill.
"This report provided the most compelling information to date that COVID-19 vaccines were performing as expected in the real world," CDC director Rochelle Walensky, MD, said in a statement. "This study, added to the many studies that preceded it, was pivotal to CDC changing its recommendations for those who are fully vaccinated against COVID-19."
The study included 1,843 healthcare workers and took place between January and March of this year at 33 sites across 25 states.
Read the full study results here.