Overview
- The study, which was published Tuesday in JAMA Network Open, reports that the updated 2025–26 COVID vaccine cut emergency and urgent care visits by about 50% and hospitalizations by about 55% among adults during September–December 2025.
- Authors used a test-negative design that compared vaccination status of patients who tested positive for COVID with those who tested negative at hospital and urgent care visits across seven states.
- CDC interim director Jay Bhattacharya delayed or blocked the paper's planned publication in the agency's Morbidity and Mortality Weekly Report in spring 2026, saying he prefers longitudinal cohort studies and raising methodological concerns.
- Career scientists and an editorial accompanying the JAMA paper defended the test-negative approach as a practical, timely tool for routine vaccine surveillance, while HHS and CDC spokespeople said additional methodological review was needed before MMWR publication.
- Experts warn that sidelining test-negative studies could slow or weaken real-time monitoring of vaccines for COVID, influenza and RSV and could erode public trust if leadership decisions appear to shape which findings reach the public.