Danish researchers proposed a United States-funded trial in Guinea-Bissau that would enroll about 14,000 newborns to compare health outcomes after receiving the hepatitis B vaccine either at birth or six weeks later. The government of Guinea-Bissau suspended the trial on January 22 pending review after the plan drew strong public and professional opposition.
Under the protocol, half the infants would be randomized to receive the WHO-recommended birth-dose vaccine, and the other half to receive the dose at six weeks, a schedule commonly used in Guinea-Bissau where supply constraints often delay the birth dose. Investigators said the design would dovetail with a planned national shift to at-birth vaccination in 2028 and estimated roughly 7,000 children would receive a birth dose earlier than they otherwise would.
Critics said the trial was unethical because it purposefully delayed an established, life-saving intervention for infants at highest risk of chronic hepatitis B infection. Newborn infection carries a much greater risk of lifelong liver disease and cancer. “It is unethical to deny children an intervention that we know works,” former health minister Magda Robalo told reporters, adding that national public health authorities had not been fully informed and that the researchers had taken advantage of the country’s limited research capacity.
The Bandim Health Project in Guinea-Bissau, affiliated with the University of Southern Denmark and long led by researchers Christine Stabell Benn and the late Peter Aaby, planned to run the study. The group has for decades investigated so-called non-specific effects of vaccines — outcomes beyond protection against targeted pathogens — and published findings suggesting certain inactivated vaccines might affect overall child mortality in some settings. Those results prompted WHO review but were judged inconsistent, and immunization recommendations for DTP and other vaccines have remained in place.
Some scientists questioned both the premise and the design. Observers asked why investigators who have argued inactivated vaccines can have harmful non-specific effects would nevertheless administer those vaccines in a randomized trial. Others pointed to methodological concerns: the study was to be open-label, meaning clinicians would know which infants received which schedule, and the five-year follow-up might be too brief to capture some hepatitis B outcomes that appear later in life.
The trial drew additional scrutiny after the US Centers for Disease Control and Prevention awarded a $1.6 million grant in December without an apparent competitive process, according to public records. That funding decision came amid broader shifts at the US health department under Secretary Robert F. Kennedy Jr., including changes to newborn vaccine recommendations and financing priorities.
Leaked protocol details published online showed the study planned to monitor for skin disorders and neurodevelopmental conditions such as autism by age five. That raised alarm because major health bodies, including WHO, state there is no credible evidence linking vaccines to autism.
Guinea-Bissau sought external review from the Africa Centres for Disease Control and Prevention after the plan became public. The country’s new government, installed after a November coup, said its health ministry had not approved the study. Critics invoked historic research abuses, such as the 1996 Trovan trial in Nigeria and the US Tuskegee syphilis study, as reasons for heightened caution and community mistrust.
Public health experts in Guinea-Bissau stressed priorities they believe are more urgent: securing reliable vaccine supply so all infants can receive the birth dose now, and strengthening local research governance and capacity. Bandim researchers defended the proposal, saying they would not withhold vaccines children would otherwise have gotten and that the trial could expand early access to birth doses for some infants. The episode highlights tensions over research ethics, power imbalances in global health, scientific uncertainty about non-specific vaccine effects, and the need for transparent engagement with local authorities and communities when research involves vulnerable populations.