CDC Cancels Publication of Scientific Report on COVID Vaccine Efficacy

Acting director Jay Bhattacharya initially pulled the report, questioning the study's methodology despite the publication of other studies using the same methodology.

Matt MacKenzie

April 23, 2026

2 min read

Key Highlights

- The CDC initially approved a report showing vaccines cut hospital visits and hospitalizations in half this past winter.
- Acting CDC director Jay Bhattacharya delayed publication over concerns about the report's methodology, despite it being previously used in other studies.
- The cancellation raises questions about political influence, with some suggesting efforts to downplay vaccine success ahead of elections.
- The CDC has not had a confirmed director since August, fueling concerns over leadership and transparency.
- Officials emphasize the importance of methodological soundness, but critics worry about potential suppression of positive vaccine data.

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The CDC canceled publication of a scientific report showing the efficacy of the COVID-19 vaccine. CIDRAP has the news.

The report was initially scheduled to be published in the CDC’s Morbidity and Mortality Weekly Report on March 19, and showed that the “COVID-19 vaccine cut the likelihood of emergency department visits and hospitalizations in half this past winter.” The report cleared the agency’s scientific review process but was delayed by acting CDC director Jay Bhattacharya over “concerns about the methodology,” despite that methodology having “long been used by the CDC to evaluate vaccine effectiveness for respiratory viruses.” It was “used in a study on the flu vaccine published last month in MMWR.”

An official from the CDC said that “taking time to ensure analyses are methodologically sound and clearly communicated is always preferable to risking error” in response to the cancellation.

A former CDC official stated that he “wasn’t aware of a report that was already cleared and scheduled for publication in MMWR being blocked by leadership during his time at the agency.” This all comes as the Trump administration seeks to “downplay efforts by HHS secretary Robert F. Kennedy, Jr. … to undo U.S. vaccine policies ahead of the midterm elections.” The CDC hasn’t had a confirmed director since August of last year.