Efficacy of COVID-19 vaccine in front-line workers wanes

The overall effectiveness of three COVID-19 vaccines remains strong but is waning, according to a study of infections in U.S. front-line workers published this week by the Centers for Disease Control and Prevention. The study reviewed data collected over 35 weeks, during which the delta variant of the coronavirus became dominant. Vaccine effectiveness fell from 91% to 66% during this period, but it is unclear whether the vaccine is less effective against the delta variant or whether its efficacy wanes over time. “This trend should be interpreted with caution,” the researchers wrote, noting the limited number of infections among study participants. “Although these interim findings suggest a moderate reduction in the effectiveness of COVID-19 vaccines in preventing infection, the sustained two-thirds reduction in infection risk underscores the continued importance and benefits of COVID-19 vaccination,” they concluded. (Becker’s Hospital Review article, 8/25/21)