On October 1, 2025, two well-known Danish vaccine researchers, Peter Aaby and Christine Stabell Benn, found themselves in deep trouble, facing threats to their careers.
A group of leading statisticians in Denmark had completed a harsh critique of their research, slated for publication in the journal Vaccine in the coming weeks. This analysis highlighted “questionable research practices” and revealed a troubling list of scientific shortcomings. It came on the heels of a damaging series of articles in the weekly paper Weekendavisen, which accused Aaby and Stabell Benn of overstating their research conclusions.
The couple, married and ages 81 and 57 respectively, gained notoriety for promoting a theory that has been embraced by vaccine skeptics: that vaccines might have unforeseen and non-specific effects on the immune system. Some vaccines, particularly those using weakened viruses, could lower mortality rates, while others made with inactivated viruses might actually increase it. They had dedicated years of research to this idea at a facility in the economically challenged Guinea-Bissau, West Africa.
Faced with months of scrutiny, the pair confronted a daunting challenge: how could they secure funding for their work amid doubts regarding their methodologies and findings?
However, just two days after the statisticians submitted their critique to Vaccine, help arrived unexpectedly from a high-ranking official within the U.S. government. On October 3, Stabell Benn engaged in private talks with Health and Human Services officials selected by Secretary Robert F. Kennedy Jr. to acquire exclusive research funding, as uncovered in emails obtained by Rolling Stone.
Stabell Benn proposed a randomized controlled trial in Guinea-Bissau. This trial would vaccinate half of 14,000 newborns with a hepatitis B birth dose while withholding it from the other half, allowing researchers to investigate potential adverse health effects like skin issues or neurodevelopmental problems.
The timing of her inquiry was described as “unsolicited” in the emails, though it coincided with Kennedy’s consideration of a controversial policy change. He had announced in mid-December that the hepatitis B vaccination, particularly the birth dose, would no longer be universally recommended, despite its acknowledged success in preventing mother-to-infant disease transmission.
In the following three months, two of Kennedy’s controversial appointees known for their anti-vaccine stance facilitated a no-bid grant for Aaby and Stabell Benn’s research. This internal communication indicated that the funding was a priority for the CDC and HHS.
Gunver Lystbæk Vestergård, a journalist from Weekendavisen, received the documents related to this funding through a freedom of information request from the University of Southern Denmark, where Stabell Benn works.
On December 18, shortly after the CDC announced it would cease recommending hepatitis B vaccinations for all U.S. children, the $1.6 million grant for the Guinea-Bissau study was quietly posted in the Federal Register. Health experts criticized this move as unethical, arguing against depriving a group of newborns of a potentially lifesaving birth dose in a region plagued by high rates of hepatitis B infections.
The emails revealed some of the inner workings of Kennedy’s administration, suggesting they were bypassing established review processes to steer funds toward researchers who shared their ideological views. Dr. Daniel Jernigan, a former CDC director, claimed that the grant did not meet basic scientific or ethical standards, likening their methods to a fishing expedition for supporting evidence.
Reports emerged that ethical concerns led the Africa CDC to reportedly suspend the study, although officials from Guinea-Bissau indicated it could resume after modifications. An HHS official remarked that they were confident the study would advance once all protocols were finalized.
Andrew Nixon, an HHS spokesperson, defended the study, claiming it aimed to address vital questions regarding the hepatitis B vaccine’s broader health implications. However, he did not directly address whether the agency adhered to typical grant review standards.
Both Aaby and Stabell Benn declined detailed inquiries from Rolling Stone and the University of Southern Denmark. They had previously staunchly defended their research findings, asserting the integrity of their hypotheses regarding vaccines’ non-specific effects on mortality rates.
Denmark has become an area of interest for the Trump administration, with the U.S. seeming to aspire to adopt some of its policies, including its reduced vaccination schedule.
On January 5, Kennedy announced a new direction for the CDC, ceasing universal recommendations for six out of 17 childhood vaccines, promoting what he portrayed as a more aligned approach with countries like Denmark. The shift faced heavy backlash from U.S. vaccine advocates, who labeled it dangerous.
Many Danish scientists expressed confusion, noting that Denmark’s vaccination program targets only ten diseases, aided by a robust national healthcare system. In fact, Denmark vaccinates against fewer diseases than other developed nations, and Danish researcher Anders Hviid speculated that Kennedy’s true goal was broader: to eliminate vaccinations entirely.
In August, Hviid himself was directly challenged by Kennedy for publishing a study that found no link between vaccine aluminum and chronic diseases like autism. Despite this, Stabell Benn praised Kennedy’s rise to power, suggesting he could catalyze a re-evaluation of existing vaccine knowledge.
Kennedy has applauded Aaby and Stabell Benn’s work publicly, emphasizing it in interviews and even labeling Aaby a “hero” in his writings. In a controversial move, he recently claimed that international vaccine purchasing group Gavi had overlooked important findings related to mortality rates linked to the DTP vaccine.
This claim incited outrage from Danish physician Charlotte Strøm, who delved into the DTP study’s origins and soon shared her findings with Vestergård. Aaby and Stabell Benn’s original claims about the DTP vaccine stemmed from a 2017 observational study, which was found to be lacking in evidential strength. By 2022, they had revised their statements, stating newfound data showed no increase in mortality.
Even as the evidence supporting their initial hypothesis crumbled, Stabell Benn and others continued to caution that vaccines were insufficiently studied for potential risks. She criticized the lack of randomized clinical trials, which are considered the gold standard of evidence, despite their earlier findings.
Strøm’s investigation led her to discover that Aaby had conducted a randomized study of the DTP vaccine years earlier but had never published the outcomes. As Vestergård began reporting on this delayed publication, it sparked widespread scandal, revealing a pattern of overstated findings.
When Stabell Benn shared partial results under pressure from public scrutiny, she asserted that their data did not conclusively support or refute claims regarding increased female mortality linked to the DTP vaccine.
Though definitive evidence remained elusive, Aaby and Stabell Benn’s overarching theory—that vaccines may have unknown effects warranting further research—formed a central argument for Kennedy’s proposed vaccine policy changes.
Emails indicate Stabell Benn’s communications with Kennedy’s associates closely paralleled the administration’s contentious discussions about no longer recommending the hepatitis B birth dose.
In early June, Kennedy reshuffled the Advisory Committee on Immunization Practices, replacing all its members with those who aligned more closely with his perspective. The first meeting of the new committee devolved into chaos, leading to a postponed vote on the hepatitis B vaccine recommendations.
Notably, Stabell Benn appeared to have submitted her grant request the day before this meeting. The following deliberations were marked by confusion and ultimately resulted in no decision on the birth dose.
On October 3, with her reputation under fire, Stabell Benn sent an email to Redwood detailing the hepatitis B study and highlighting their urgent need for funding. She mentioned that the Pershing Square Foundation had committed $1.8 million if they could match that amount within a month.
The subsequent communications suggested a rapid escalation in securing funding. Stabell Benn pointed out that Guinean officials planned to introduce the hepatitis B vaccination in 2027, which aligned with the timeline of their proposed study.
Concerns were raised that the study design was driven more by Kennedy’s interests than scientific inquiry, especially given its focus on lesser-explored outcomes. Many professionals worldwide condemned the project for knowingly denying life-saving intervention to a group of newborns.
Dr. Paul Offit likened the ethical breaches surrounding the study to historical medical injustices, decrying the manipulation of these circumstances as a way to support Kennedy’s theories.
Despite the controversies, most Danish medical professionals have continued to advocate for following proven scientific principles. In 2024, health officials in Denmark expressed strong support for adding the hepatitis B vaccine to their national immunization schedule.
