Guinea-Bissau cancels US-funded hepatitis B vaccine trial for newborns

Guinea-Bissau has cancelled a proposed clinical trial for the hepatitis B vaccine involving newborn infants. The decision follows intense scrutiny and accusations that the study design was unethical. The trial, which was planned to involve 14,000 babies, was intended to split participants into two groups: one receiving the vaccine shortly after birth and the other receiving no shot. The cancellation comes after police seized a batch of vaccines from the research centre involved in the project.

The study was designed to be conducted at the Bandim Health Project, a research facility that has operated in the country since 1978. It was funded by the United States, with the Centers for Disease Control and Prevention (CDC) awarding $1.6 million to the University of Southern Denmark (SDU) in December 2025. The funding occurred under the administration of US Health Secretary Robert F Kennedy Jr, who has previously expressed scepticism regarding vaccines. The primary objective stated by the researchers was to investigate whether administering the hepatitis B vaccine at birth has broader health effects beyond simply preventing infection.

Background

The controversy centred on the ethical implications of withholding a recommended medical intervention. The World Health Organization (WHO) recommends that infants receive the hepatitis B vaccine at birth. However, Guinea-Bissau, like many neighbouring countries, currently waits until babies are six weeks old to administer this vaccination. Researchers argued that this delay provided a unique opportunity to study the vaccine's effects before routine birth-dose vaccination is introduced in the country in 2028.

Critics, including public health experts, argued that the trial would deny critical protection to thousands of infants in one of the world's poorest countries. Characterizing the initiative as neocolonial, they argued that at-risk groups in Africa were being subjected to hazards that scientists would never permit in affluent countries. Previous studies in The Gambia and Guinea-Bissau had raised questions about a possible link between the birth-dose vaccine and increased mortality, which the researchers cited as a reason for the need for further investigation. However, opponents maintained that the risk of withholding a proven vaccine outweighed the scientific benefit of the study.

Walter Kazadi Mulombo, the WHO representative in Guinea-Bissau, expressed concern after receiving inquiries about the study and noting the lack of a publicly available protocol. He stated that the main ethical issue was the withholding of an intervention that has been used for more than 30 years in over 115 countries. Mulombo cautioned that infants might contract the virus during delivery if their mothers carried the infection, or at a subsequent stage in their development. He described a study that withholds this protection from newborns as unethical.

Why it matters

The decision to halt the trial has significant implications for public health policy and ethical standards in international medical research. Approximately 20% of Guinea-Bissau's residents have hepatitis B, a viral condition that impacts the liver. The widespread nature of the infection in the region underscores the importance of effective vaccination strategies. The incident has drawn international criticism, highlighting tensions between scientific inquiry and the duty of care owed to vulnerable populations in low-resource settings. The seizure of vaccines by police indicates a direct governmental intervention to stop the distribution of the materials intended for the trial.

The BBC has requested a comment from the US Department of Health and Human Services regarding the cancellation. The funding source, the CDC, and the implementing university, SDU, have not yet provided a public response to the allegations of unethical conduct. The controversy serves as a case study in the challenges of conducting clinical trials in regions where standard of care differs from global health recommendations. It raises broader questions about how research ethics are enforced when studies are conducted in countries with different regulatory frameworks and healthcare capacities.

What happens next

The immediate next step is the cessation of all trial activities related to the hepatitis B vaccine study in Guinea-Bissau. The country is scheduled to introduce routine hepatitis B vaccinations at birth in 2028, a timeline that remains unchanged by the cancellation of this specific trial. The seized vaccines are currently in police custody, and it is unclear whether they will be returned to the health system or destroyed. The WHO and other international health bodies may review the protocols and oversight mechanisms for future research in the region to ensure that ethical standards are met. The US government and the University of Southern Denmark are expected to address the funding and implementation issues that led to the trial's termination.