Covid vaccine efficacy wanes after 6 months without booster shot, study suggests

According to a new study published in The Lancet Respiratory Medicine, the efficacy of the Covid-19 vaccination may diminish significantly after six months if booster doses are not received.

According to the study, immunizations were 94% effective at avoiding hospitalisation 50-100 days after being given the shot, but only 80.4 percent effective 200-250 days later, with even faster reductions after 250 days.

“This data helps us understand differences in waning protection by vaccine type and identify the key risk factors for severe breakthrough infections to help inform the targeting of potential vaccine booster programmes,” said Amy Compton-Phillips, Providence chief clinical officer.

“Unlike most other studies, our data stretched beyond six months, where we found evidence of rapidly waning protection, especially for patients 80 or older,” Compton-Phillips added.

In addition to examining the effectiveness of vaccines over time, the Providence study was also able to identify factors associated with reduced vaccine effectiveness.