CDC weighs $1.6M for newborn hepatitis B trial amid ethics outcry

The study would have tested whether the hepatitis B dose given at birth has hidden, nonspecific harms on infant health. Under the original plan, published in a US government notice in December 2025, about 14,000 newborns would be enrolled. Half would get the vaccine at birth. The other half would wait until six weeks of age.

The research team is the Bandim Health Project, which has worked in Guinea-Bissau for decades and is linked to the University of Southern Denmark. It is led by married researchers Christine Stabell Benn and Peter Aaby, with Frederik Schaltz-Buchholzer also leading the trial. Their theory is that live vaccines such as BCG, the tuberculosis shot, may lower overall child deaths beyond the disease they target, and that adding a hepatitis B shot at the same time might weaken that benefit.

The CDC first announced an unsolicited $1.6 million grant to the group in December. Private backers were to match it, including the Pershing Square Foundation, which billionaire Bill Ackman helped found, and the Bluebell Foundation.

The core objection is simple: the vaccine already works, so holding it back from babies to test a theory puts them at risk for no proven reason. Guinea-Bissau has some of the world’s highest hepatitis B rates, with about 18% of adults carrying the virus. Babies infected in their first year are far more likely to become chronic carriers, and long-term infection can scar the liver, cause cancer and shorten lives.

The World Health Organization said in February that the trial rested on hypothetical safety outcomes without enough credible evidence to justify the risk. WHO chief Tedros Adhanom Ghebreyesus called the design unethical at a press conference that month. The agency recommends a first dose for every infant as soon as possible after birth, ideally within 24 hours, followed by at least two more.

Paul Offit, an infectious disease doctor at Children’s Hospital of Philadelphia, called the theory behind the study “fanciful,” pointing out that the vaccine is one protein among the billions a baby’s immune system meets every day. Hundreds of millions of children worldwide have either had the birth dose or not, he argued, so any real problem would already be obvious.

Consent was another sticking point. Families who declined to join would not get the birth dose at all. Henrik Støvring, a statistics professor at Aarhus University in Denmark, put it this way: joining gave a mother a 50% chance her child got the shot, while staying out gave her none. Experts say that makes truly free consent impossible.

The researchers changed the plan after the first wave of criticism. Mothers would now be tested for hepatitis B before giving birth. Babies of mothers who tested positive would get the vaccine right away and stay out of the study. Babies in the comparison group would receive a saline placebo rather than no injection, and every baby in both groups would still get the routine hepatitis B-containing shots at six, ten and 14 weeks.

Critics said this did not solve the problem. About half of the children who catch hepatitis B do so after birth, from family members or the community, not from their mothers. The virus can survive on surfaces for up to seven days and spread through shared items like toothbrushes or washcloths. The mother’s test also misses about 5% of infections, Offit noted, which could give false comfort.

Even the ethics approval was contested. A research ethics committee at the University of Southern Denmark, which had never reviewed a medical study before, approved the project on September 30. Stig Børsen Hansen, one of its founding members, quit in protest, describing the setup as entering newborns in a lottery. Three other members also resigned.

Guinea-Bissau first suspended the study in January, with Public Health Minister Quinhin Nantote saying there had not been enough coordination to make a final decision. When reports in early October said the trial had been cleared, Nantote went public on October 13 to say his ministry had not authorized it.

The country’s Council of Ministers then formally rejected the study on October 16, Stabell Benn confirmed in an email. Days later, judicial police searched Bandim Health’s offices in the country and seized the vaccine doses meant for the trial. Stabell Benn said the search came after the rejection, and that her team regretted the decision but respected the government’s right to make it.

Schaltz-Buchholzer wrote on LinkedIn that it was now clear the study would not move forward in Guinea-Bissau because it lacked government approval. He also said the debate had left some local families wondering whether the vaccine was being tested on Africans because it was dangerous. Both vaccine schedules are safe, he wrote, though he still defended the research question.

For families here, nothing about the hepatitis B shot itself has changed. It has a decades-long record of being safe and effective, and Offit credits the US birth-dose program with nearly wiping out hepatitis B in American children within a few years.

The bigger issue is trust. The trial was backed by Health and Human Services Secretary Robert F. Kennedy Jr., a longtime vaccine critic who praised the Danish researchers at an anti-vaccine conference. Offit has said Kennedy’s goal is to drop the US birth dose, and critics feared the trial would supply data for that push. When a public health agency funds research that outside experts call unjustified, it can shake confidence in vaccine advice more widely.

If you’re a parent with questions about the newborn schedule, your pediatrician or family doctor is the best person to talk to. The WHO’s guidance on a birth dose within 24 hours has not changed.

The funding for the trial was to come from the CDC’s global health security programs, money that critics noted could otherwise go to work such as fighting the Ebola outbreak in the Democratic Republic of the Congo. The CDC has not said whether the $1.6 million will now be used to vaccinate all newborns in Guinea-Bissau instead, as the WHO recommends and as Offit has urged.

Guinea-Bissau currently plans to add a universal hepatitis B birth dose to its schedule in 2028. Separately, Stabell Benn and Aaby are still being investigated in Denmark over claims of research misconduct, including alleged falsification, in their earlier vaccine studies.