COVID-19 vaccine boosters bolster protection against hospitalization but the effect wanes over time, according to a study published Feb. 11. Researchers with the Centers for Disease Control and Prevention (CDC) and other institutions found the booster effectiveness against emergency department or urgent care (ED/UC) visits held at 87 percent during the first two months after a third dose of the Pfizer or Moderna vaccine, but dropped to 66 percent between four and five months after receipt of the booster. Protection against hospitalization also decreased over time, from 91 percent in the first two months after the booster to 78 percent four or more months after the third dose. “The finding that protection conferred by mRNA vaccines waned in the months after receipt of a third vaccine dose reinforces the importance of further consideration of additional doses to sustain or improve protection against COVID-19–associated ED/UC encounters and COVID-19 hospitalizations,” the researchers …