The Standing

A daily, non-partisan record of US democratic norms — and the events that erode them.

    CDC blocks publication of cleared MMWR study showing COVID vaccine effectiveness

    A CDC scientific report finding that the 2025–2026 COVID-19 vaccine roughly halved healthy adults' risk of emergency-department visits and hospitalizations was scheduled to run in the agency's flagship Morbidity and Mortality Weekly Report on March 19, 2026, after clearing internal scientific review. Acting CDC Director Jay Bhattacharya blocked its publication, objecting to the study's test-negative design — a methodology the CDC has long used to measure vaccine effectiveness and that appeared in an MMWR flu-vaccine study the prior month. A former CDC immunization director called blocking an already-cleared, scheduled MMWR report unprecedented.

    Jurisdiction
    federal
    Location
    Atlanta, Georgia (CDC / HHS)

    Abuses documented

    Actors

    • Jay Bhattacharya (Acting Director, Centers for Disease Control and Prevention)
    • U.S. Department of Health and Human Services (HHS)

    On March 19, 2026, a scientific report finding that the 2025–2026 COVID-19 vaccine roughly halved healthy adults' risk of emergency-department visits and hospitalizations was scheduled to appear in the CDC's Morbidity and Mortality Weekly Report (MMWR). The report had cleared the agency's internal scientific review. Acting CDC Director Jay Bhattacharya blocked its publication, citing objections to the study's test-negative design — a methodology the CDC has used for years to measure vaccine effectiveness and that appeared in an MMWR flu-vaccine study published the prior month.

    Demetre Daskalakis, the former director of the CDC's National Center for Immunization and Respiratory Diseases, said he was not aware of any prior instance of an already-cleared, scheduled MMWR report being blocked by leadership, calling the move a departure from the agency's transparent scientific practice. In response to a query, a CDC official did not address the blocked report specifically but said the agency applies the "highest standards of scientific rigor" to what it publishes.

    The block came amid HHS Secretary Robert F. Kennedy Jr.'s broader rollback of U.S. vaccine policy. Kennedy, who oversees the CDC, had announced in May 2025 that the COVID-19 vaccine would no longer be recommended for pregnant women and healthy children, and the agency has been without a Senate-confirmed director since Susan Monarez was pushed out in August 2025 after refusing to fire top CDC officials over vaccine directives.

    The event is dated to March 19, 2026 — the scheduled publication date from which the study was pulled. The suppression was first reported publicly by the Washington Post on April 22, 2026. It is related to but distinct from the May 18, 2026 NIAID–WHO communication restrictions (entry federal-censoring-agency-research-44478511).

    Why we recorded this

    The public relies on federal health agencies to report what their own scientists find, even when the results are politically inconvenient. The CDC's Morbidity and Mortality Weekly Report is the agency's authoritative scientific channel, and its findings reach the doctors, states, and members of the public who use them to make health decisions. When political leadership blocks an already-cleared, peer-reviewed study because its conclusion — that the COVID-19 vaccine roughly halved hospitalizations and emergency-department visits — conflicts with the administration's posture, it substitutes ideology for evidence and withholds government data the public is entitled to see. The Standing records this as censoring agency research and suppression of government data: an intrusion on the independence of federal science and on public access to the findings that public institutions produce.

    Sources

    1. CDC blocks publication of report showing COVID vaccine efficacy — CIDRAP (University of Minnesota) primary accessed June 10, 2026
    2. COVID vaccine report blocked at CDC's MMWR — The Washington Post primary accessed June 10, 2026
    3. HHS rejects publication of study showing Covid-19 vaccines prevent hospitalizations, ER visits — CNN secondary accessed June 10, 2026
    4. After pulling vaccine study, Bhattacharya criticizes long-running CDC publication — Science (AAAS) secondary accessed June 10, 2026

    See also