Why It Matters

A Senate hearing on COVID-19 vaccines and alleged attacks on scientific publications put the Trump administration's skeptical posture toward pandemic-era public health institutions on full display on Wednesday, June 3, as Sen. Ron Johnson (R-WI) convened a panel of doctors who argued mRNA vaccines may cause cancer and that their research has been systematically suppressed. The hearing's sharpest tension emerged not between senators, but between Johnson and Julie Gralow, the chief medical officer of the American Society of Clinical Oncology, who defended the scientific consensus while Johnson pressed her on what she did and didn't know about vaccine mechanics.

The Big Picture

The June 3 hearing before the Senate Permanent Subcommittee on Investigations is the third in a series Johnson has run in the 119th Congress on COVID vaccine safety. It follows an April 2025 hearing on Biden-era health officials and vaccine safety signals, which produced an interim report titled "Unmasked: How Biden Health Officials Purposely Turned a Blind Eye Toward COVID-19 Vaccine Injury Safety Signals." That hearing directly preceded this one. The series also builds on a May 2025 hearing focused on myocarditis linked to COVID vaccines.

The Trump administration has taken steps broadly aligned with the hearing's framing, including halting CDC vaccine promotion campaigns, curtailing COVID vaccine recommendations through HHS, and, according to reporting by the New York Times and BMJ, blocking publication of FDA studies that supported vaccine safety. That last development created an awkward dynamic: both sides of the debate are now accusing the other of suppressing science.

What They're Saying

The hearing's central dispute, whether mRNA COVID vaccines can cause or accelerate cancer and whether researchers raising that question have been silenced, produced sharp exchanges throughout.

  • Angus Dalgleish, Professor Emeritus of Oncology at City St. George's, University of London, called for an outright ban: "Its use for future vaccines should be banned, and the COVID ones stopped now."
  • Wafik El-Deiry, Director of the Legorreta Cancer Center at Brown University, framed the issue as one of scientific freedom: "Scientists deserve the freedom to investigate legitimate scientific concerns."
  • Gralow pushed back directly: "There is no clinical evidence proving that mRNA COVID-19 vaccines cause cancer."

The most contentious exchange came when Johnson pressed Gralow on whether she understood that the mRNA in COVID vaccines was modified with pseudouridine and was not standard mRNA. When she acknowledged uncertainty about lipid nanoparticle biodistribution, Johnson shot back: "You're saying how safe and effective this is, but you don't know how it works." Gralow responded that she does know how it works, that it incites an immune reaction, but the exchange illustrated the hearing's broader dynamic: Johnson using technical questions to undercut the credibility of the mainstream scientific position.

Sen. Richard Blumenthal (D-CT), the ranking member, used his time to pivot. He cited the National Cancer Institute's conclusion that "there is no evidence that COVID-19 vaccines cause cancer, lead to recurrence, or lead to disease progression," and then shifted to what he called the real threat: the Trump administration's cuts to cancer research funding. He submitted for the record a JAMA study of nearly 30 million people, finding that vaccinated individuals were less likely to die from cancer four years after vaccination.

Blumenthal asked Gralow directly whether cutting NIH research funding would cost lives. Her answer was unequivocal: "Absolutely."

Sabine Hazan, CEO of ProgenaBiome, described a series of her published studies being retracted, including a 2021 paper on COVID in patient feces, a 2022 paper on ivermectin-based therapy, and a 2024 paper on cardiac safety of hydroxychloroquine. She argued the retractions were politically motivated: "If there was a treatment, vaccines would not have passed."

Saskia Mostert, a Dutch researcher, described the institutional response to her team's 2024 BMJ Public Health study on excess mortality across 47 Western countries as "blind fury," and said that while the study found no plagiarism or falsification, her institution still sought retraction. Aseem Malhotra, a British cardiologist at the HUM2N Clinic in London, described himself as "a grieving vaccine injured doctor" and accused multinational pharmaceutical corporations of meeting the criteria for psychopathy as defined by forensic psychologists.

Tamika Felder, a 25-year cervical cancer survivor and patient advocate, offered the hearing's most direct counterpoint to the vaccine-skeptical witnesses. She said attacks on the HPV vaccine would cost lives: "No one in the United States of America should die of cervical cancer."

Political Stakes

For Johnson, the hearing is the capstone of a sustained, months-long messaging campaign. In the 30 days before the hearing, he posted repeatedly on vaccine adverse events, VAERS data suppression, and what he described as a government cover-up. He has no immediate re-election concerns, and the series reinforces his standing with the Republican base on COVID accountability. The risk is that several of the studies underpinning the hearing's witnesses have faced scrutiny: the Guardian reported on June 4 that three papers used by the Trump administration to justify vaccine policy changes had been retracted or placed under investigation by their journals.

The FDA's own suppression of pro-vaccine safety studies, reported weeks before the hearing, created a mirror-image narrative: Democrats can argue the actual science censorship is happening inside the Trump administration, not in peer-reviewed journals targeting vaccine skeptics.

The Other Side

Gralow acknowledged that further research on vaccine-related cancer signals may be warranted, and she agreed that cancer patients would want to know if any drug or vaccine increased their risk. But she drew a firm line on what the existing evidence shows, noting that cancer develops over years or decades and that "the appearance of late-stage aggressive tumors within weeks or months of an injection is biologically incompatible with what we've learned from decades of research." She also cited a Vanderbilt University study showing cancer patients who received COVID vaccines had a 50 percent reduction in hospitalization risk.

Democratic members were largely absent from the proceedings. Blumenthal departed mid-hearing for a Veterans Affairs Committee ranking member obligation. No other Democratic members spoke on the record, continuing a pattern that Sen. Ashley Moody (R-FL) noted after Sen. Rand Paul's May COVID Cover-up hearing: "Jarring to witness not a single Democrat participate."

What's Next

Johnson has signaled the series will continue. The subcommittee's interim report from April remains active, and the pattern of escalating hearings suggests a formal subcommittee report or legislative referral is possible. Upcoming pressure points include FDA and NIH reauthorization cycles, where the hearing record could inform appropriations riders or oversight language.

The Bottom Line

The hearing put two irreconcilable scientific narratives on the same dais, with each side accusing the other of suppressing the truth, and no resolution in sight.

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