Repeated warnings about COVID shots, and Biden admin did nothing

Sen. Ron Johnson (R-Wis.)’s latest COVID-19 vaccine oversight report, released April 29, 2026, alleges that Biden-era FDA officials ignored internal warnings that the agency’s existing vaccine safety surveillance system had a known blind spot and declined to adopt a newer data-mining method that allegedly identified dozens of additional statistically significant safety signals.

Those warnings came from Dr. Ana Szarfman, then a senior FDA official working in the FDA’s Center for Drug Evaluation and Research (CDER), who told FDA officials in early 2021 that their vaccine safety surveillance system had a known blind spot because of “masking,” a data limitation that can inhibit the detection of safety signals.

Szarfman collaborated with Dr. William DuMouchel, then Oracle’s chief statistician and the inventor of the data-mining algorithm supporting the FDA’s existing system, to implement an updated methodology called the Regression-Adjusted Gamma Poisson Shrinker (RGPS) and compare its results against the FDA’s existing Multi-item Gamma Poisson Shrinker (MGPS) method.  Szarfman and DuMouchel claimed that RGPS was better able to adjust for “masking” in the data, meaning the FDA’s existing system could allow safety signals to go undetected.

On March 26, 2021, Szarfman shared an analysis that found “49 examples of extreme masking,” with more than 20 adverse-event examples showing a statistically significant safety signal after adjusting for masking.  Johnson’s report states that these safety signals included adverse events such as sudden cardiac death, Bell’s palsy, and pulmonary infarction that the FDA’s existing methodology had not previously detected.

Szarfman and DuMouchel shared similar analyses at least three other times, in April, May, and July 2021.  Their analyses

yielded even more statistically significant safety signals with higher values for adverse events, including acute myocardial infarction associated with Moderna and Pfizer-BioNTech (“Pfizer”) COVID-19 vaccines, non-site specific embolism and thrombosis associated with the Janssen (“Johnson & Johnson”) and Pfizer vaccines, dementia associated with the Pfizer vaccine, and Death and sudden death” associated with the Moderna and Pfizer vaccines.

Szarfman wrote emails to FDA officials warning them about the limitations of the FDA’s MGPS system.  However, in May 2021, FDA officials directed Szarfman to “hold off on creating and sending data mining reports and analyses,” and in September 2021, Dr. Peter Marks warned Dr. Patrizia Cavazzoni, then-director of CDER,  that Szarfman’s work could “create erroneous conflicts that feed into anti-vaccination rhetoric.”  Despite being told to “hold off,” Szarfman continued to generate and distribute her and DuMouchel’s analyses.

By May 24, 2021, federal health officials had acknowledged that, for “the age groups 16–17 years and 18–24 years,” the Vaccine Adverse Event Reporting System (VAERS) was unambiguously “signaling for myopericarditis.”  According to Johnson’s report, despite that evidence, Biden health officials “continued to fail to immediately warn the public” about COVID-19 vaccine–related cardiac events.

In addition, a key document trail shows that FDA officials acknowledged the limitation Szarfman had flagged.  In September 2021, Dr. David Menschik noted in a draft that the FDA’s existing empirical Bayesian (E.B.) data-mining system had “multiple limitations” and that COVID vaccine reports could mute disproportionality scores, especially if both mRNA products were associated with the same adverse event.  His draft language, the report notes, appeared in preprint versions of a vaccine safety paper but was removed before final publication in The Lancet.  In that same month, Szarfman continued to urge senior FDA officials to utilize her and DuMouchel’s data-mining system, underscoring that their method was “much better at unmasking signals than MGPS.  It automatically identifies and corrects for confounders.  This is an important function to have, given the pandemic situation,” she added.

The report goes on to highlight concerns over access and transparency regarding COVID-19 vaccine data.  The FDA had been sending weekly COVID-19 data-mining reports to CDC officials.  However, records show that in 2022, the FDA stopped routinely sending them.  One CDC official later wrote, “I think that because of the FOIAs we may have asked the FDA to stop sending these weekly data mining outputs.”  Johnson’s report notes that this happened after FOIA requests and congressional requests sought the same E.B. data-mining analyses.

The issue highlighted in Johnson’s report is not whether every VAERS signal proves causation, but rather whether federal health officials had warning signs, knew there were blind spots associated with the existing surveillance tool, and still rejected Szarfman’s proposed fix while limiting distribution of safety data and continuing to reassure the public that the vaccines were safe and effective.

The report builds on Johnson’s long-running COVID vaccine safety oversight, dating back to 2021, including letters to CDC, FDA, NIH, and HHS about adverse-event reports, safety surveillance systems, myocarditis in young people, “hot lots” and lot-variation data, VAERS data, and E.B. data-mining analyses.  Johnson also convened several public roundtables to discuss the COVID-19 vaccines, which he and other critics have described as “experimental mRNA gene therapy,” while federal health agencies repeatedly assured the public that the vaccines were “safe and effective.”  On May 21, 2025, Johnson released an interim report from the U.S. Senate Permanent Subcommittee on Investigations alleging that federal health agencies “downplayed the risk of myocarditis and other adverse events following COVID-19 vaccination.”

Following that, in December 2025, Johnson wrote a letter to HHS Secretary Robert F. Kennedy, Jr. about Dr. Vinay Prasad’s memo on child deaths following COVID vaccination, as well as continued reports of myocarditis and the Biden administration’s extension of COVID vaccine liability protections.  Prasad’s memo stated, among other things, that Biden health officials failed in numerous ways “to take seriously” the dangers of the COVID-19 vaccines, especially in children ages 7 to 16, stating that “we may have harmed more children than we saved.”  Johnson questioned in the same letter why the FDA allegedly reviewed only 96 death reports when VAERS had reported 38,913 worldwide deaths associated with the vaccines as of Nov. 28, 2025.

In March 2026, Johnson also released nearly 2,000 pages of Biden HHS records and preliminary findings showing that, as early as November 2022, federal vaccine safety systems had detected a statistically significant ischemic stroke safety signal in individuals 65 and older following the Pfizer bivalent booster.

Johnson’s March 2026 release states that “rather than immediately issue a formal warning to the public, documents show that in December 2022, the Biden White House and HHS pushed to ‘increase uptake of the booster’ for people 65 years and older.” Johnson’s investigation further alleged that discussion of the safety signal continued into 2023, including a draft CDC-FDA “communications plan” that appeared to underscore the Biden administration’s continued desire to “increase uptake of the booster” while continuing to downplay the concerning safety signals associated with the mRNA vaccines.

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