JAMA NetworkOdds of Hospitalization for COVID-19 After 3 vs. 2 Doses of mRNA COVID-19 Vaccine by Time Since Booster Dose

This case-control study carried out at six hospitals between Oct 2021 and July 2022 found that boosters yielded a 75% reduction in COVID hospitalization risk in the first 50 days post-booster, declining to 25% reduction in hospitalization risk at over 150 days. Other factors associated with an increased odds of hospitalization for COVID-19 included age of 70 years or older, male sex, cognitive disease, COPD, diabetes, immunodeficiency, obesity, rheumatologic disease, transplant, and Pfizer-BioNTech vaccination.