Hepatitis B vaccine trial in Guinea-Bissau halted after global backlash

The lead researcher of a study on hepatitis B vaccination for newborns in Guinea-Bissau — a project funded by the U.S. Centers for Disease Control and Prevention (CDC) that drew widespread international criticism — said on Wednesday that the study has been halted.

Frederik Schaltz-Buchholzer, a Danish researcher, wrote on LinkedIn that it is now "clear" the study "will not be implemented in Guinea-Bissau," adding: "we did not receive the necessary authorization from the government."

Earlier, Guinea-Bissau's health minister, Quinhin Nantote, denied the project would go ahead. "This is not even close to the truth," Nantote told The Guardian in Portuguese last week.

The study was set to receive $1.6 million from the CDC, along with another $1.6 million from private partners including the Pershing Square Foundation, backed by billionaire Bill Ackman, and the Bluebell Foundation.

"The solution here is obvious: take the money and vaccinate as many children as possible," said Paul Offit, a vaccine expert at Children's Hospital of Philadelphia who sharply criticized the proposed study as unethical.

Guinea-Bissau's government has now taken control of the research team's vaccine stocks after authorities searched the offices of the Bandim Health Project on Monday.

According to Offit, helping Guinea-Bissau vaccinate all newborns as soon as possible is essential. The country currently expects to offer universal newborn vaccination in 2028.

The Danish research team, led by Schaltz-Buchholzer, Christine Stabell Benn and Peter Aaby, hypothesized that live vaccines such as the BCG tuberculosis shot may offer benefits for overall mortality beyond protection against diseases like TB — but that giving another vaccine such as hepatitis B at the same time could blunt that effect.

Offit called the hypothesis "far-fetched," arguing that the hepatitis B vaccine is a single protein among billions of substances the immune system encounters every day.

"There's no evidence for it, and it's not biologically plausible," he said. He also stressed the clear benefits of vaccinating children as early as possible, given the country's high hepatitis B rates and the risk of lifelong illness and death from infection.

The Danish researchers did not respond to questions about the study or the criticism by the time of publication. The CDC also did not answer whether the funding, allocated through its global health work, will now be used to vaccinate all newborns in Guinea-Bissau in line with World Health Organization (WHO) recommendations.

"WHO recommends that all newborns receive their first hepatitis B vaccine dose as soon as possible after birth — ideally within 24 hours — followed by at least two more doses," said WHO spokesperson Tarik Jašarević. "WHO remains committed to working with national authorities, researchers and partners to ensure that every newborn — in Guinea-Bissau and worldwide — is protected promptly and on the basis of evidence against hepatitis B."

According to experts, those who declined to take part in the study would not receive the vaccine — making genuine informed consent impossible.

"Imagine you are a mother. You want the best for your child," said Henrik Støvring, a Danish researcher who co-published studies questioning earlier Bandim Project research.

"If they decide to join the trial, they have a 50% chance their child gets vaccinated. But if they don't join, that chance is 0%. So how can you call that informed consent without coercion?" Støvring asked.

According to Schaltz-Buchholzer, the proposal eroded trust among people in Guinea-Bissau, with many asking whether the vaccine — which has a decades-long record of safety and effectiveness — was being tested on Africans because it is dangerous.

He wrote that it "needs to be clear" that both newborn vaccination schedules — with or without the hepatitis B vaccine — are not "dangerous to anyone." Experts say giving the hepatitis B vaccine at birth has clear benefits, and failing to do so can lead to lifelong risk.

According to Offit, conducting such a study "creates the argument that there is something worth studying, when they have no evidence."

"We have millions, maybe hundreds of millions of children around the world who have or have not received this vaccine at birth. If there were any evidence this was a problem, you would know by now," Offit added. "We eliminated hepatitis B in children in the U.S. in just a few years after starting the program, so the benefit is clear."

Schaltz-Buchholzer also questioned the effectiveness and safety of the hepatitis B vaccine given at birth, saying he believed the study was canceled because it challenged "common medical assumptions, such as that the hepatitis B shot at birth has no non-specific effects." Beyond mortality, the study was also set to examine side effects such as skin conditions and neurodevelopmental conditions. Dozens of studies have shown no link between vaccination and autism.

"All newborns should get a hepatitis B vaccine at birth," Offit said. "Guinea-Bissau is a country with a high rate of chronic hepatitis B. You could argue that this country, more than any other, needs to start this program."