Contents
- 1 The COVID Vaccine Report the CDCTried to Hide Is Finally Out
- 2 What the Delayed Report Found
- 3 The Official Response and the Methodology Question
- 4 A Timeline of Recent Federal Vaccine Policy Changes
- 5 COVID Vaccine Access Revised for Certain Groups
- 6 HHS Vaccine Study Plan in Guinea-Bissau Reported
- 7 CDC COVID Vaccine Study Hold Placed by Acting Director
- 8 Washington Post Reports the Delay
- 9 What Researchers and Officials Are Saying
- 10 What Comes Next
The COVID Vaccine Report the CDC
Tried to Hide Is Finally Out
A report from the Washington Post has revealed that Jay Bhattacharya, the acting director of the Centers for Disease Control and Prevention, delayed publication of a CDC study examining the effectiveness of COVID-19 vaccines. Two CDC scientists, speaking to the Post anonymously, said the study found that vaccinated adults had significantly lower rates of urgent care visits and hospitalizations compared to unvaccinated individuals. HHS cited methodology concerns as the reason for the delay. The episode has drawn scrutiny from public health officials and researchers who question the grounds for the hold.
What the Delayed Report Found
According to two anonymous CDC scientists who spoke to the Washington Post, the delayed study found that healthy adults who received a COVID vaccine reduced their risk of urgent care visits by 50 percent and their risk of hospitalization by 55 percent, compared to unvaccinated individuals.
The report had been scheduled for publication on March 19 in the Morbidity and Mortality Weekly Report (MMWR), the CDC’s peer-reviewed research journal. Acting CDC director Jay Bhattacharya placed a hold on the publication, with HHS citing concerns about the study’s methodology.
“Dr. Bhattacharya wants to make sure that the paper uses the most appropriate methodology for such a study.”
— Andrew Nixon, Spokesperson, Department of Health and Human ServicesThe Washington Post noted that a separate report examining flu vaccine effectiveness — using the same methodology — was published in MMWR the week prior without a hold. That detail has prompted questions from some public health researchers about the basis for the methodology objection in the COVID vaccine study specifically.
The Official Response and the Methodology Question
HHS spokesperson Andrew Nixon stated that the delay was procedural, not substantive — that Bhattacharya wanted to ensure the study met the highest methodological standards before publication. The agency has not released a detailed explanation of what specific methodology concerns were identified or what changes, if any, would be required before the report could proceed.
Former CDC safety director Daniel Jernigan offered his assessment of the situation to the Washington Post, noting the timing of the delay in the context of broader federal vaccine policy.
“The secretary has already taken steps to try and remove the availability of the vaccine from children and others. So if you’re putting out an MMWR that the vaccine is effective at preventing hospitalizations and medical care visits… that message is not in line with the direction you’ve been taking with the removal of the vaccine.”
— Daniel Jernigan, Former CDC Safety DirectorHHS Secretary Robert F. Kennedy Jr. has previously made public statements expressing skepticism about COVID vaccines. In 2025, the FDA moved to limit access to COVID vaccines for certain groups. HHS has said those decisions are based on an ongoing review of the benefit-risk profile of the vaccines for different populations.
“He has a fixed, immutable belief that vaccines cause harm. He will do everything he can to try and prove that.”
— Paul Offit, Director, Vaccine Education Center, Children’s Hospital of Philadelphia — speaking to The GuardianA Timeline of Recent Federal Vaccine Policy Changes
The delayed MMWR publication comes amid a series of federal policy changes affecting vaccine access and research. Here is a factual timeline of key developments:
COVID Vaccine Access Revised for Certain Groups
The FDA moved to limit COVID vaccine availability for specific populations. HHS stated the changes were based on a benefit-risk reassessment. Public health organizations raised concerns about reduced access.
HHS Vaccine Study Plan in Guinea-Bissau Reported
Reports emerged of a proposed HHS study in Guinea-Bissau, West Africa, that would involve withholding hepatitis B vaccines from approximately 7,000 newborns. Medical experts raised ethical concerns. The study’s current status has not been confirmed.
CDC COVID Vaccine Study Hold Placed by Acting Director
Jay Bhattacharya places a hold on the scheduled MMWR publication of a COVID vaccine effectiveness study. HHS cites methodology concerns. A flu vaccine study using the same methodology had published in MMWR the prior week.
Washington Post Reports the Delay
Two anonymous CDC scientists speak to the Washington Post about the delayed publication, bringing public attention to the study’s findings and the circumstances of the hold.
What Researchers and Officials Are Saying
Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia and a prominent voice in vaccine research, has been publicly critical of HHS leadership’s approach to vaccine policy. His comments, originally made to The Guardian in the context of the Guinea-Bissau study, reflect a broader concern among some medical researchers about the direction of federal vaccine oversight.
Daniel Jernigan’s remarks frame the publication delay within the context of recent federal policy decisions, raising the question of whether scientific publication timelines are being influenced by policy considerations. HHS has not responded to that specific characterization.
The MMWR has historically operated as an editorially independent scientific journal. Publication decisions have generally been made by CDC scientists and editors. Whether and how the current delay will be resolved — and when or whether the study will ultimately be published — has not been publicly announced by HHS or the CDC.
What Comes Next
The delayed CDC study found that COVID vaccines reduced urgent care visits by 50% and hospitalizations by 55% among healthy adults — findings consistent with a broad body of existing research on vaccine effectiveness. HHS has said the delay is a matter of methodological review. Public health researchers have noted that the same methodology was accepted without objection in a flu vaccine study published the same week. The study has not been published as of this writing. HHS has not indicated a timeline for resolution.
