Vaccine Effectiveness Against Infection May Wane, C.D.C. Studies Find
Three studies were released by the Centers for Disease Control and Prevention that provided evidence that booster shots for the Pfizer-BioNTech and Moderna coronavirus vaccines would be needed in upcoming months. Some experts disagree and say the evidence does not back up the decision to recommend booster shots to all Americans. The research shows the vaccines remain effective against hospitalizations and deaths, but protection against infection as a whole has weakened.
The decline in effectiveness may have resulted from waning vaccine immunity, not following precautionary measures, such as wearing masks, the rise of the Delta Variant, or all three. There have been plans outlined for Americans to receive a booster vaccine eight months after their second doses, and would begin on September 20. The new studies reveal the overall effectiveness of the vaccines against infection is 55%, and 90% or higher against symptomatic infection, and 90% or higher against hospitalization.