The effectiveness of COVID-19 vaccine booster doses dropped well under 50 percent after four months against subvariants of the virus that causes COVID-19, according to a new study from the U.S. Centers for Disease Control and Prevention (CDC).
The Moderna and Pfizer vaccines provided just 51 percent protection against emergency department visits, urgent care encounters, and hospitalizations related to COVID-19 during the time BA.2 and BA.2.12.1, subvariants of the Omicron virus variant, were predominant in the United States, CDC researchers found.
Both vaccines are administered in two-dose primary series.
After 150-plus days, the effectiveness dropped to just 12 percent.
A first booster upped the protection to 56 percent, but the effectiveness went down to 26 percent after four months, according to the study, which drew numbers from a network of hospitals funded by the CDC across 10 states called the VISION Network….