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Leaked CDC paper shows 2025, 26 COVID vaccine 53, 55% effective, publication blocked

scienceApr 27, 2026141,091

Inside Medicine published a leaked CDC study showing the 2025, 26 COVID-19 vaccine was 53, 55% effective at preventing hospitalizations during September, December 2025. The publication says CDC and NIH officials blocked the paper's appearance in the Morbidity and Mortality Weekly Report and identifies acting CDC director Jay Bhattacharya as involved in that decision. The study measured protection among adults without immune compromise in the months after vaccination, suggesting the 2025, 26 formula provided moderate protection and should inform booster and public health planning.

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