News > Covid booster efficacy wanes significantly by 4th month

Covid booster efficacy wanes significantly by 4th month

The efficacy of third doses of the Pfizer and Moderna mRNA vaccines wanes substantially by the fourth month after administration, a new study by the US Centres of Disease Control and Prevention said Friday.

Though it's now well documented that vaccine efficacy goes down after two doses, relatively little has been published on the duration of protection after a booster.