The Food and Drug Administration and the Centers for Disease Control and Prevention recently authorized a second booster shot of the Pfizer/BioNTech and Moderna COVID-19 vaccines for those age 50 and older. The recommendation follows a study out of Israel recently published in The New England Journal of Medicine.
The Israel study reports a modest relative risk reduction in COVID-19 infections for those receiving a second booster compared to those who have gotten one booster, on the order of 1.5 times lower, with this benefit waning over the length of the study period, or around two months.
The study also reported a significant relative risk reduction in severe cases of COVID-19 following a second booster, on the order of 3.5 times lower, with this benefit enduring during the length of the study period. It is not yet known whether this benefit will persist into the future.
