A new CDC study finds the mRNA COVID-19 vaccines authorized by the Food and Drug Administration (Pfizer-BioNTech and Moderna) reduce the risk of infection by 91 percent for fully vaccinated people.
This adds to the growing body of real-world evidence of their effectiveness. This study is among the first to show that mRNA vaccination benefits people who get COVID-19 despite being fully vaccinated (14 or more days after dose 2) or partially vaccinated (14 or more days after dose 1 to 13 days after dose 2). “COVID-19 vaccines are a critical tool in overcoming this pandemic,” said CDC Director Rochelle P. Walensky, MD, MPH. “Findings from the extended timeframe of this study add to accumulating evidence that mRNA COVID-19 vaccines are effective and should prevent most infections — but that fully vaccinated people who still get COVID-19 are likely to have milder, shorter illness and appear to be less likely to spread the virus to others. These benefits are another important reason to get vaccinated.”
In the new analysis, 3,975 participants completed weekly SARS-CoV-2 testing for 17 consecutive weeks (from December 13, 2020 to April 10, 2021) in eight U.S. locations. Participants self-collected nasal swabs that were laboratory tested for SARS-CoV-2, which is the virus that causes COVID-19. If the tests came back positive, the specimens were further tested to determine the amount of detectable virus in the nose (i.e., viral load) and the number of days that participants tested positive (i.e., viral shedding). Participants were followed over time and the data were analyzed according to vaccination status.
Once fully vaccinated, participants’ risk of infection was reduced by 91 percent. After partial vaccination, participants’ risk of infection was reduced by 81 percent. These estimates included symptomatic and asymptomatic infections. The CDC are advising people to get vaccinated as soon as possible. In the United States, anyone 12 years or older is eligible for the vaccine.
ARTICLE: PAUL MURDOCH
MANAGING EDITOR: CARSON CHOATE
PHOTO CREDITS: LA TIMES