The U.S. Centers for Disease Control and Prevention, or CDC, said a study conducted between February and August found that the effectiveness of COVID-19 vaccines declines over time, especially in people over 65 years of age. The research showed a similar pattern in the Pfizer and Moderna vaccines, both based on messenger RNA technology.
The U.S. Centers for Disease Control and Prevention, or CDC, said a study conducted between February and August found that the effectiveness of COVID-19 vaccines declines over time, especially in people over 65 years of age. The research showed a similar pattern in the Pfizer and Moderna vaccines, both based on messenger RNA technology.