A report showing the Covid-19 vaccine's efficacy in reducing hospitalisations has been blocked from publication. Photo / 123RF
A report showing the efficacy of the Covid-19 vaccine that was previously delayed by the head of the United States Centres for Disease Control and Prevention has been blocked from being published in the agency’s flagship scientific journal, three sources say.
The report showed that the vaccine reduced emergency department visits and hospitalisations among healthy adults by about half this past northern winter.
The move, which has not been previously reported, has raised concerns among current and former officials that information about the vaccine’s benefits is being downplayed because they conflict with the views of US Health Secretary Robert F. Kennedy jnr, who has been an outspoken critic of the shots.
Kennedy’s vaccine agenda has received pointed questioning from lawmakers during budget hearings that began last week and conclude today.
The Washington Post reported two weeks ago that Jay Bhattacharya, who is temporarily overseeing the CDC, delayed publication of the report over concerns about methodology. It had been scheduled for publication on March 19 in the Morbidity and Mortality Weekly Report.
In recent days, a decision was made that the report would not be published, according to two of the people familiar with the decision who spoke to the Post.
Andrew Nixon, a spokesman for the Department of Health and Human Services, which oversees the CDC, confirmed the delay two weeks ago.
At that time, he said it was “routine for CDC leadership to review and flag concerns about MMWR papers, especially relating to their methodology, leading up to planned publication”.
Nixon said that Bhattacharya had raised concerns about “the observational method used in the study to calculate vaccine effectiveness” and that the scientific team was working to address them.
Bhattacharya, director of the National Institutes of Health, is leading the CDC while Erica Schwartz, a top health official during US President Donald Trump’s first term, awaits Senate confirmation.
Yesterday, Nixon described the decision differently: “The MMWR’s editorial assessment identified concerns regarding the methodological approach to estimating vaccine effectiveness and the manuscript was not accepted for publication”, a characterisation that differs from accounts by people familiar with the report’s review.
The report is gaining attention at a delicate political moment: the Trump Administration has sought to soften its public posture on controversial vaccine actions before the US Midterm elections.
Republican pollsters have warned of the political risks of vaccine scepticism, and many voters oppose Kennedy’s efforts to roll back vaccine policies.
Publishing findings showing the vaccine’s effectiveness would be at odds with the Administration’s moves to restrict its use, particularly for children, former CDC officials say.
The report had cleared the agency’s scientific-review process, which includes dozens of scientists, according to two of the three people who spoke to the Post. Stopping an MMWR report at that stage is highly unusual, former CDC officials say.
“I cannot recall CDC stopping an MMWR report in the publication phase after scientific clearance and editorial review. On rare occasions we shifted the timing slightly to better align communications plans with competing or reinforcing pieces,” Michael Iademarco, who was the director of the CDC centre with oversight of the MMWR from 2014 to 2022, said.
Bhattacharya had concerns about a methodology that has long been used by the CDC to evaluate vaccine effectiveness for respiratory viruses, including influenza.
A report about flu vaccine effectiveness this past northern winter – using the same methodology – was published in the MMWR a week earlier. An HHS official had previously said Bhattacharya was not in a position to review the earlier study and would have raised the same concerns.
A report using this methodology to gauge Covid vaccine effectiveness in children was published in MMWR in December.
The methodology was also used in a 2021 study on Covid vaccine effectiveness in clinics and hospitals published in the New England Journal of Medicine.
Vaccine effectiveness estimates using the same methodology have also been published in other peer-reviewed journals, including JAMA Network Open, the Lancet and Paediatrics.
An HHS official said that Bhattacharya met scientific staff and that the report’s authors did not want to adjust their methodology.
Kennedy, founder of a prominent anti-vaccine group, once referred to Covid-19 shots as the “deadliest vaccine ever made”.
Last year, he posted a video on X directing the CDC to stop recommending the vaccine for healthy pregnant women and children – an unprecedented move that bypassed the agency’s long-standing process of relying on its federal vaccine advisory panel.
The decision drew widespread criticism from medical and public health experts.
Kennedy has said he is not anti-vaccine but is seeking to give Americans transparency and medical choice.
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