- The CDC chose not to publish a vaccine study, criticizing its scientific approach.
- However, the study was later published by JAMA, showing that the vaccine significantly reduced COVID-related hospitalizations.
- Some critics suspect the decision to withhold the research was influenced by political motives.
Recently, JAMA Network Open released a COVID-19 vaccine study that the Centers for Disease Control and Prevention (CDC) opted not to publish back in March.
The research indicated that the vaccine cut emergency department visits and hospitalizations for COVID-19 by about half last winter among adults, effectively lowering the risk of severe illness. This was true even for those who had previously been vaccinated or infected.
CDC officials stated that the study was not published in the Morbidity and Mortality Weekly Report due to its purported failure to meet rigorous scientific standards. Yet, critics of this rationale suggest there may have been a political agenda behind the decision.
Michelle Barron, one of the authors and a senior medical director for UCHealth in Colorado, mentioned to a reporter that the scientific merit was never the real issue. She implied, perhaps a bit cautiously, that it was within the CDC’s rights to withhold the study, but the reasoning for this was likely not rooted in scientific grounds.
She speculated that the withholding might be connected to opposition from Health and Human Services Secretary Robert F. Kennedy Jr. regarding this specific vaccine and its underlying science.
An HHS spokesperson, Emily Hilliard, firmly dismissed this theory, stating that the CDC doesn’t base scientific judgments on predetermined outcomes. She asserted that they rely on comprehensive evidence evaluations and uphold rigorous methodologies before releasing studies.
The findings
The study involved 85,725 emergency department visits and 26,073 hospitalizations from September to December 2025, focusing on adults aged 18 and over who were not immunocompromised—since those individuals already face a higher risk of severe illness.
It included patients with symptoms consistent with COVID-19 who had been tested for the virus within ten days before or three days after their hospital or urgent care visit.
Results suggested that the effectiveness of the 2025-26 COVID-19 vaccines was about 50% for preventing urgent care or emergency services and about 55% for avoiding hospitalization compared to unvaccinated individuals.
For adults aged 65 and older, effectiveness estimates were somewhat lower—approximately 48% for avoiding urgent care and 53% for preventing hospital stays.
The study concluded that getting vaccinated during the 2025-2026 period provided additional protection against medically attended COVID-19 beyond existing immunity among adults, suggesting that vaccination could help minimize severe outcomes linked to COVID-19.
Background on the controversy
Dr. Jay Bhattacharya, who was acting director of the CDC at the time, criticized the test-negative design of the study, despite it being a well-established method for assessing vaccine effectiveness that the CDC has used in flu vaccine monitoring for years.
He also remarked that the CDC’s publication, unlike JAMA Network Open, which recently published the study, was not peer-reviewed—a point he made to highlight the difference in credibility.
In an editorial accompanying the study in JAMA, Natalie Dean from Emory Rollins School of Public Health acknowledged that researchers were indeed aware of the study’s limitations. However, she emphasized that the design had its advantages over other observational studies, despite noting potential biases related to health-seeking behavior—where those more likely to get vaccinated also tend to seek medical help sooner when they show symptoms.
Furthermore, reports have surfaced indicating that the U.S. Food and Drug Administration previously blocked studies showcasing the safety of both COVID and shingles vaccines, raising questions about research transparency. According to earlier articles, significant taxpayer funding was involved in these studies, which reported minimal risks and demonstrated overall safety for the vaccines.
One notable study analyzed 7.5 million Medicare records to evaluate the safety of the COVID-19 vaccine in older adults, concluding that it was safe. Although this study received acceptance from Drug Safety—a peer-reviewed journal—it was ultimately withdrawn.
