Controversial US study on hepatitis B vaccines in Africa cancelled
By The Guardian, January 18, 2026The controversial US-funded study on hepatitis B vaccines among newborns in Guinea-Bissau has been halted, according to Yap Boum, a senior official at the Africa Centres for Disease Control and Prevention (CDC).
“The study has been cancelled,” Boum told journalists at a press conference on Thursday morning.
The $1.6m (Ksh207M) study, funded under the purview of Robert F Kennedy Jr, a longtime vaccine sceptic and the secretary of the US Department of Health and Human Services (HHS), drew outrage and criticism over ethical questions about withholding vaccines proven to prevent hepatitis B in a country with a very high burden of the disease.
“It’s of importance for Africa CDC to have evidence that can be translated into policy, but this has to be done within the norm. So we are glad that at this point the study is being cancelled,” Boum said. The study was halted because it raised critical questions on the ethics of the trial, he said, adding: “The way the study was designed was a big challenge.”
Officials in Guinea-Bissau say the trial will still happen, according to one journalist on the press call. But Africa CDC officials said the trial would only move forward once it has been redesigned to address ethical issues.
There were “still some conversations happening” between Guinea-Bissau officials and the US on how to conduct a trial like this ethically, and Africa CDC, which is not affiliated with the HHS, had assembled a team to make sure Guinea-Bissau officials “receive the adequate support to ensure that this study, if it has to happen, will also fit the ethical regulations”, Boum said.
The design of the study has not been made public by the researchers or by health officials, but a leaked version was published by Inside Medicine on Thursday. An HHS official told the Guardian after publication that the protocol is now being updated and the leaked version is not finalised. That would mean the trial would not proceed as it has been described so far.
Timeline for when the study would be finalised
The official did not offer a timeline for when the study would be finalised, but said the US was trying to move as quickly as possible before vaccines roll out to all Guinea-Bissau newborns in 2027. “This study is going to proceed as planned,” the official said.
Yet a senior official in Guinea-Bissau said that the trial has been cancelled due to ethical concerns about the study design, according to a letter obtained by the Guardian on Friday. Guinea-Bissau will continue its current vaccination schedule until the birth dose is implemented for all newborns, the letter said.
The Danish researchers conducting the trial have also been criticised for not publishing the results of a study on the diphtheria-tetanus-pertussis (DTP) vaccine, potentially because it contradicted their belief that the vaccine is dangerous, according to the Danish journalist Gunver Lystbæk Vestergård.
Frederik Schaltz-Buchholzer, one of the Danish researchers, also shared some details on social media. Titanji didn’t find his argument compelling. “It actually just raises even more concerns in my mind,” she said.
The researchers argue that some types of vaccines may bring nonspecific effects – improving overall health, not just against the disease the vaccine is targeting. But, they say, adding other kinds of vaccines, such as those for hepatitis B, could interfere with these possible effects. Yet the evidence to support possible overall health effects is based upon the researchers’ prior research, which has been called into question.
Other Danish researchers analysed these studies and found no statistically significant effects, according to their new preprint study, which has not been peer-reviewed or published yet. One of the researchers on that study, Anders Hviid, said on LinkedIn that these findings were especially important given recent decisions in the US to limit several vaccines for children.
The Danish researchers also argued that trials should be done in Africa in order to study their effects on African children.