US-Backed Hepatitis B Vaccine Trial in Guinea-Bissau Halted

A planned hepatitis B vaccine trial in newborns in Guinea-Bissau will not go forward, the study's lead researcher said Wednesday, after the government denied the approval the project needed. Frederik Schaltz-Buchholzer, a Danish researcher on the study, wrote on LinkedIn that it was "now clear" the trial "will not move forward in Guinea-Bissau," adding that "we were not given the necessary governmental approval," according to The Guardian.

Why Was the Trial Halted?

The halt followed public denials from Guinea-Bissau's health ministry that the study would proceed. Health Minister Quinhin Nantote told the Guardian in Portuguese the week before the announcement that reports of the trial moving forward were "not even remotely true," per the October 21, 2026 Guardian report. Guinea-Bissau's government has since taken physical control of the vaccines the researchers had on hand, seizing them when officials searched the offices of the Bandim Health Project on Monday, the Guardian reported.

What Did the Study Aim to Test?

The trial was designed around a hypothesis developed by a team of Danish researchers, including Schaltz-Buchholzer, Christine Stabell Benn and Peter Aaby. Their theory held that live vaccines, such as the Bacillus Calmette-Guérin (BCG) shot used against tuberculosis, may carry a broader mortality benefit for infants beyond protection against the specific disease they target, according to the Guardian. The researchers hypothesized that administering a hepatitis B vaccine alongside BCG at birth could blunt that broader protective effect, which is what the Guinea-Bissau trial was built to examine.

Who Funded the Research?

The study carried two funding streams of equal size, both reported by the Guardian. The US Centers for Disease Control and Prevention had committed $1.6 million to the project. A second $1.6 million was slated to come from private partners, including the Bill Ackman-backed Pershing Square Foundation and the Bluebell Foundation. The Guardian's reporting lists these as separate, parallel commitments rather than a single combined grant, and no source material specifies a consolidated total.

What Do Critics Say About the Study's Ethics?

Paul Offit, a vaccines expert at the Children's Hospital of Philadelphia, sharply criticized the proposed trial as unethical, the Guardian reported. Offit argued the funding would be better spent expanding access to the hepatitis B vaccine itself rather than testing whether it should be paired with BCG.

"The solution is clear here: take the money and vaccinate as many kids as you can," Offit told the Guardian.

Offit said it was vital to support Guinea-Bissau in rolling out immunizations to all newborns as soon as possible, according to the Guardian's account.

What Happens to Guinea-Bissau's Vaccine Rollout Now?

Guinea-Bissau currently plans to offer a universal hepatitis B birth dose — meaning every newborn, not a trial subset — starting in 2028, the Guardian reported. That timeline was already in place before the controversy over the Danish-led study surfaced, and it remains the government's stated plan following the trial's collapse. The government's seizure of the researchers' existing vaccine stock, taken during Monday's search of Bandim Health Project offices, puts those doses under state rather than research-team control going forward, per the Guardian.

Figures at a Glance

• CDC funding commitment to the now-halted trial: $1.6 million, per the Guardian's October 21, 2026 report.
• Private funding commitment from the Pershing Square Foundation and the Bluebell Foundation: $1.6 million, separately listed in the same report.
• Guinea-Bissau's planned start year for a universal newborn hepatitis B birth dose, independent of the trial: 2028, per the Guardian.

The dispute underscores a recurring tension in global vaccine research: whether resources earmarked for experimental study design should instead fund direct, immediate rollout of an already-approved vaccine. Guinea-Bissau's government and the study's Danish leadership have offered conflicting public accounts of whether the trial was ever cleared to proceed, with Nantote denying any approval and Schaltz-Buchholzer's LinkedIn post confirming after the fact that none had been granted. No further details on the disposition of the seized vaccines, or on whether the CDC or private funders will redirect their committed funds, were included in the available reporting.