Effectiveness of the COVID-19 vaccine is found to decline after 6 months without boosters as per a study published in the journal The Lancet Respiratory Medicine by Providence.
The study scrutinized data from nearly 50,000 hospital admissions between April and November of 2021. It was found that the vaccines had 94% efficacy at preventing hospitalization 50-100 days after receiving the shot.
‘Overall effectiveness of COVID-19 vaccines in preventing severe infection shows a substantial decline in protection after six months, thereby mandating the nations plan to prioritize booster programs.’
However, the efficacy fell to 80.4% after 200-250 days with an even more rapid decline after 250 days. The study also identified factors associated with reduced vaccine effectiveness that included advanced age of more than 80 years, comorbidities like hypertension, cancer, chronic kidney disease, transplants, or heart failure, the elapsed time since vaccinated, and the type of vaccine.
The Moderna vaccine was found to offer the best protection overall. However, the Pfizer-BioNTech vaccine presented only initial protection similar to Moderna’s with rapid decline over time.
“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 programs. Unlike most other studies, our data stretched beyond six months, where we found evidence of rapidly waning protection, especially for patients 80 or older. We were also able to identify important differences by vaccine type and patient characteristics that should help inform potential booster programs,” says Amy Compton-Phillips, MD, Providence chief clinical officer.
Source: Medindia
