CDC study shows COVID shot benefits; Trump official blocks release – Ars Technica

Study found shots cut urgent care and hospitalization by about 50% in healthy adults.
Under anti-vaccine Health Secretary Robert F. Kennedy Jr., scientists at the Centers for Disease Control and Prevention have been blocked from publishing a scientifically vetted study finding significant health benefits from this season’s COVID-19 vaccines, according to reporting by The Washington Post.
The move adds to longstanding concern among health experts that chaos and political interference under Kennedy—a staunch anti-vaccine activist who has long falsely maligned COVID-19 vaccines—is deeply undermining science at federal agencies and beyond.
CDC scientists and insiders told the Post that the COVID-19 vaccine study went through the agency’s standard scientific review process and was slated for publication on March 19 in the agency’s Morbidity and Mortality Weekly Report (MMWR). But acting CDC director Jay Bhattacharya blocked the scheduled publication and is holding the study, claiming he has concerns about its methodology.
Agency scientists talked with the Post on the condition of anonymity for fear of retaliation from the Trump administration.
According to a summary the Post obtained, the study concluded that between September and December of last year, healthy adults vaccinated with a 2025–2026 COVID-19 vaccine saw the risk of emergency department or urgent care visits cut by 50 percent, and the risk of COVID-19-associated hospitalizations cut by 55 percent, compared with healthy adults who did not get this season’s shot.
Bhattacharya reportedly took issue with the test-negative design of the study, which is a well-established method to examine real-world data on vaccine effectiveness. This type of observational study looks at people who have symptoms related to the disease of interest (in this case, COVID-19) and have the same test-seeking behavior. Those who test positive for the disease of interest become positive cases in the study, and those who test negative are test-negative controls. Researchers then compare the two groups based on vaccination status.
Test-negative case-control design studies have been widely used to assess the effectiveness of many types of vaccines. In fact, the CDC published a study in the MMWR last month—a week before the COVID-19 study was set to publish—examining this year’s flu shot effectiveness with the same design. But the method gained a higher profile during the pandemic, with hundreds of studies using it to estimate COVID-19 vaccine effectiveness. Analyses have found that, like any observational study design, there are potential biases, but it’s generally considered to produce reliable estimates when those biases are controlled.
Andrew Nixon, spokesperson for the Department of Health and Human Services, which oversees the CDC, told the Post in a statement that “It’s routine for CDC leadership to review and flag concerns about MMWR papers, especially relating to their methodology, leading up to planned publication.”
Nixon said Bhattacharya, who is also head of the National Institutes of Health under Kennedy, was concerned by “the observational method used in the study to calculate vaccine effectiveness” and “wants to make sure that the paper uses the most appropriate methodology for such a study.” Nixon added that the agency’s “scientific team is working to address these concerns.”
Dan Jernigan, who headed CDC’s influenza division for six years and resigned last year in protest of Kennedy’s political interference at the agency, suggested to the Post that stalling the paper fits with Kennedy’s anti-vaccine agenda.
“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,” he said.
Ars Technica has been separating the signal from the noise for over 25 years. With our unique combination of technical savvy and wide-ranging interest in the technological arts and sciences, Ars is the trusted source in a sea of information. After all, you don’t need to know everything, only what’s important.

source