A controversial US-funded study examining hepatitis B vaccination among newborns in Guinea-Bissau has been halted, according to a senior official at the Africa Centres for Disease Control and Prevention.
Yap Boum, deputy incident manager at Africa CDC, confirmed the decision at a press conference on Thursday, saying the study had been cancelled following widespread concern over its ethical design.
The $1.6m project, funded through the US Department of Health and Human Services under the oversight of Robert F Kennedy Jr, had drawn strong criticism for proposing to withhold a proven hepatitis B vaccine from some infants in a country with one of the world’s highest burdens of the disease.
Boum said Africa CDC supported research that could inform public health policy, but only when conducted within accepted ethical standards. He said the way the trial was designed raised serious concerns and made its continuation untenable in its current form.
Officials in Guinea-Bissau indicated that the trial could still go ahead, according to journalists on the press call. Africa CDC officials, however, said any future study would require a full redesign to address ethical issues.
Boum said discussions were ongoing between Guinea-Bissau and US authorities, and that Africa CDC had assembled a team to ensure local officials received adequate support if the study were to proceed.
Guinea-Bissau has experienced political upheaval following a coup in November, with senior government officials, including those at the health ministry, replaced. Attempts to reach former officials were unsuccessful, with ministry contact details reportedly no longer functioning.
Paul Offit, an infectious diseases specialist at Children’s Hospital of Philadelphia and a former adviser to the US Food and Drug Administration, welcomed the decision. He described the cancellation as deeply encouraging and said the proposed trial was unethical.
Offit said the study would have denied life-saving vaccines to thousands of children based on random allocation. He argued the funding should instead have been used to vaccinate as many newborns as possible.
The US Department of Health and Human Services did not respond to questions about why the trial was halted.
Boghuma Titanji, an assistant professor of medicine at Emory University, said the decision could mark a turning point for research ethics in Africa. She described the halt as a victory for advocacy and said poorly designed studies could cause long-term harm well beyond their conclusion.
The researchers behind the trial had argued that it would provide hepatitis B vaccines to 7,000 newborns who would otherwise not receive them. Critics countered that this approach would knowingly deprive an equal number of infants of protection against a potentially fatal disease.
Hepatitis B remains widespread in Guinea-Bissau, affecting an estimated 18 per cent of adults and around 11 per cent of children under one. Infection in early childhood significantly increases the risk of chronic liver disease, including cancer.
The country currently administers the hepatitis B vaccine at six weeks of age due to supply constraints, but plans to introduce universal vaccination at birth in 2027 as availability improves.
Offit compared the proposed study to the Tuskegee syphilis experiment, in which effective treatment was deliberately withheld from African American men in the United States.
The Danish researchers leading the trial have also faced criticism for failing to publish findings from earlier vaccine studies. Critics allege this may be because the results contradicted their claims about vaccine safety.
Although the study protocol has not been formally released, a leaked version was published by Inside Medicine. Some details were also shared publicly by one of the researchers, Frederik Schaltz-Buchholzer. Titanji said those explanations raised further concerns rather than addressing them.
The researchers argue that live vaccines may provide broader health benefits beyond their target diseases and that adding an inactivated vaccine such as hepatitis B could interfere with those effects. However, the evidence supporting these claims has been disputed by other scientists.
A recent preprint study by Danish researchers found no statistically significant benefits from the effects cited by the trial’s authors. One of the study’s authors, Anders Hviid, said the findings were particularly relevant given recent moves in the US to limit childhood vaccine recommendations.
While Titanji agreed that more trials should be conducted in Africa, she said they must be led by African scientists and driven by local priorities. She said studies exploiting vaccine shortages did not solve public health problems and instead risked worsening them.
The trial was scheduled to begin on 5 January. When contacted earlier, the lead researchers, Peter Aaby and Christine Stabell Benn, dismissed concerns raised in earlier reporting and defended the study. They did not respond to further requests for comment following news of its cancellation.
Aaby and Stabell Benn have ties to officials in the Trump administration. Stabell Benn previously hosted a podcast with Tracy Beth Høeg, now an FDA official known for questioning vaccine safety and advocating reduced immunisation schedules.
Kennedy has previously praised Aaby’s work, citing it when he withdrew US funding from Gavi, the Vaccine Alliance, although subsequent research by the same group produced different findings.
