Guinea-Bissau has blocked a controversial US-funded Hepatitis B vaccine trial involving approximately 14,000 newborn babies, following international outrage over plans to delay potentially lifesaving vaccinations for thousands of infants. The decision has raised serious questions about Washington’s funding of medical research in poorer African countries and the ethical responsibilities of foreign researchers operating in vulnerable communities.
The West African country refused to grant the necessary government approval for the study, which had secured $1.6 million in funding from the United States Centers for Disease Control and Prevention (CDC) under Health Secretary Robert F. Kennedy Jr.
The proposed trial would have divided approximately 14,000 newborns into two groups, with half receiving the hepatitis B vaccine immediately after birth and the others receiving their first dose at six weeks, in accordance with Guinea-Bissau’s existing vaccination schedule.
Researchers intended to monitor the children’s health outcomes to investigate whether receiving the vaccine at birth had broader effects on infant mortality, illness and development.
However, the proposal provoked widespread criticism from international health experts, who warned that deliberately delaying a proven medical intervention could expose thousands of African babies to preventable infections and potentially lifelong health complications.
The World Health Organization (WHO) raised serious objections to the study’s scientific justification, ethical safeguards and research design.
In a statement issued in February, the WHO warned that withholding an established lifesaving intervention could expose newborns to irreversible harm, including chronic hepatitis B infection, cirrhosis and liver cancer.
The organisation also rejected the argument that Guinea-Bissau’s limited healthcare resources justified conducting such research, stressing that poverty and restricted access to treatment must not be exploited to lower ethical standards.
US funding and concerns over medical experimentation
The trial was developed by the Bandim Health Project, a research organisation operating in Guinea-Bissau and affiliated with the University of Southern Denmark.
The project was led by researchers Christine Stabell Benn and Peter Aaby, whose work has examined the broader health effects of vaccines beyond their intended protection against specific diseases.
Their research has attracted controversy over claims concerning possible unintended consequences of certain childhood vaccinations.
The involvement of the American government intensified scrutiny of the proposed experiment.
Kennedy, who oversees US health agencies, has faced longstanding criticism for his public statements questioning vaccine safety and established immunisation policies.
Under his leadership, the CDC awarded $1.6 million towards a study that critics argued was scientifically questionable and ethically unacceptable.
The controversy also prompted concern among American lawmakers. Democratic members of the US House Energy and Commerce Committee questioned the CDC’s decision to finance the research, citing its potential risks to African infants.
The proposed experiment was particularly controversial because the effectiveness of hepatitis B vaccination in preventing infection was already well established.
The WHO recommends administering the vaccine within 24 hours of birth to protect infants against transmission of the virus, particularly from infected mothers.
Approximately 90% of newborns infected during childbirth develop chronic hepatitis B, placing them at increased risk of serious liver disease later in life.
Guinea-Bissau has a particularly high burden of hepatitis B, with the WHO estimating that more than 12% of adults were living with chronic infection in 2022.
Despite this, the country’s limited healthcare resources have prevented the routine introduction of the hepatitis B birth dose, which authorities plan to implement nationally by 2028.
Researchers argued that the period before the national rollout presented an opportunity to compare the effects of immediate vaccination with the country’s existing immunisation schedule.
They maintained that no participating child would receive fewer vaccinations than those already provided under national policy, while thousands would benefit from earlier protection.
However, the WHO rejected the ethical justification for the proposed design, warning that the availability of an effective vaccine created an obligation to minimise preventable risks to participating children.
The dispute exposed a wider concern about the unequal relationship between wealthy countries financing medical research and poorer nations whose populations become the subjects of experimentation.
Guinea-Bissau rejects the trial
Guinea-Bissau’s government initially suspended the project in January while its ethical and scientific implications were reviewed.
The review involved national authorities and consultations with international public health organisations, including the Africa Centres for Disease Control and Prevention and the WHO.
The country’s transitional government, which assumed power following a military coup in November 2025, also raised concerns about the approval process.
Although the researchers continued defending the proposed study, Guinea-Bissau’s authorities ultimately refused to authorise its implementation.
Health Minister Quinhin Nantote publicly rejected claims in October that the project had received permission to proceed.
On October 19, judicial police searched Bandim Health Project facilities in the capital, Bissau, and seized a batch of hepatitis B vaccines.
Authorities said investigations were continuing into the circumstances surrounding the vaccines and compliance with national requirements. The seizure itself did not establish that the vaccines were unsafe or defective.
Bandim researcher Frederik Schaltz-Buchholzer subsequently confirmed that the project would not proceed because the necessary government authorisation had not been obtained.
The researchers have continued to defend the scientific basis of their work, arguing that the trial was intended to investigate broader health outcomes rather than question the established effectiveness of hepatitis B vaccination against the disease.
Nevertheless, the cancellation represents a significant setback for the US-backed project.
For Guinea-Bissau, the controversy has brought renewed attention to questions of national sovereignty, medical ethics and the responsibility of foreign institutions conducting research in African countries.
It has also highlighted an uncomfortable contradiction: while the United States was prepared to finance a multimillion-dollar experiment involving African newborns, Guinea-Bissau was still working towards securing routine access to the very vaccine at the centre of the controversy.
The case raises fundamental questions about how international medical research is funded, whose interests determine research priorities and whether vulnerable populations in poorer countries receive the same protections expected in wealthier nations.
