Largest CDC COVID-19 Vaccine Study in Healthcare Workers Shows High Protection Results
The study was conducted throughout 25 states.
- By Shereen Hashem
- May 19, 2021
A new CDC study shows that COVID-19 mRNA vaccines authorized by the FDA protect healthcare personnel (HCP) against COVID-19. mRNA vaccines, including: Pfizer-BioNTech and Moderna, reduced the risk of getting sick with the disease by 94 percent among HCP who were fully vaccinated. This assessment was conducted in a large sample size across a broader geographic area than in the clinical trials that confirms vaccine effectiveness in the U.S. for healthcare workers.
“This report provided the most compelling information to date that COVID-19 vaccines were performing as expected in the real world,” said CDC Director Rochelle P. Walensky, MD, MPH. “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.”
Data from the CDC comes from covering 500,000 HCP across 33 sites in 25 states. The vaccination process compared participants who tested positive to those who tested negative. According to a press release, among the 1,843 participants there were 623 cases and 1,220 controls. “Vaccine effectiveness estimates were calculated by comparing the odds of COVID-19 vaccination in cases and controls.”
The assessment concluded symptomatic cases were reduced by 94 percent among HCP who were fully vaccinated. 82 percent of those who were partially vaccinated defined this study 14 days after receiving the first dose through six days after the second dose. These findings support the CDC’s recommendation that everyone should get both doses of an mRNA vaccine to be most protected.
Shereen Hashem is the Associate Content Editor for Occupational Health & Safety magazine.