A study released in The Lancet Respiratory Medicine by Providence, one of the largest health systems in the United States, confirms the overall effectiveness of vaccines in preventing severe infection resulting in hospitalization from COVID-19, but also shows a substantial decline in protection after six months. Completed by a team of clinicians and scientists in the Providence Research Network, the study examined data from nearly 50,000 hospital admissions between April and November of 2021, finding that vaccines were 94% effective at preventing hospitalization 50-100 days after receiving the shot but fell to 80.4% 200-250 days later, with even more rapid declines after 250 days.
Study: COVID vaccine effectiveness declines after 6 months without boosters
A study released in The Lancet Respiratory Medicine by Providence, one of the largest health systems in the United States, confirms the overall effectiveness of vaccines in preventing severe infection resulting in hospitalization from COVID-19, but also shows a substantial decline in protection after six months. Completed by a team of clinicians and scientists in the Providence Research Network, the study examined data from nearly 50,000 hospital admissions between April and November of 2021, finding that vaccines were 94% effective at preventing hospitalization 50-100 days after receiving the shot but fell to 80.4% 200-250 days later, with even more rapid declines after 250 days.