CDC to Conduct Hepatitis B Vaccine Trial in Guinea-Bissau, Raising Ethical Concerns

The U.S. Centers for Disease Control and Prevention (CDC) approved a $1.6 million grant to fund a study on the efficacy of the hepatitis B vaccine Dec. 15, 2025. 

After U.S. Secretary of Health and Human Services Robert F. Kennedy Jr. proposed outsourcing the study to Guinea-Bissau, the Bissau-Guinean government suspended the study following significant backlash from scientists and global health experts. The CDC’s grant to study the vaccine was awarded two weeks after Kennedy removed the CDC’s long-established recommendation to vaccinate all children at birth, though the vaccine is widely recognized as safe and effective.

Babatunji Oni, the senior program director at the Center for Global Health Practice and Impact at Georgetown University, said the existing vaccine has been very successful in reducing hepatitis B in children. 

“Since universal hepatitis B vaccination of infants in the US was endorsed in 1991, the incidence of hepatitis B infection in children has dropped by 99%,” Oni wrote to The Hoya.

Hepatitis B is a virus that leads to either acute or chronic infection of the liver. This can result in the development of liver cancer and cirrhosis, which is the scarring of the liver in the final stages of infection. Hepatitis B spreads through contact with infected bodily fluids, and can also be passed from mother to baby. 

The vaccine is widely recommended because it provides nearly 100% protection against the virus. 

Oni said the proposed trial raises ethical concerns because it would delay vaccination for infants in the trial, and would not include screening of pregnant women. 

“In this study, half of the infants would get the hepatitis B vaccine at birth, while administration of the first dose would have been delayed until six weeks of age in up to 7,000 of these children,” Oni wrote. “Additionally, pregnant women were not going to be screened for hepatitis B, which would have identified children at higher risk of infection.” 

This setup would have transgressed typical ethical procedures for clinical trials by denying participating children access to the vaccine, Oni added. 

“According to the Declaration of Helsinki, ethical medical research requires that participants in the control group of a randomized trial receive the best known and proven intervention,” Oni wrote. “This trial would have denied children the best proven intervention at birth — despite the vaccine being available.” 

The Declaration of Helsinki is a set of ethical principles created by the World Medical Association, an independent organization representing physicians and promoting ethical standards of care. The declaration guides medical research involving human test subjects and helps advise researchers on fundamental ethical considerations. 

Sean Aas, a senior research scholar at the Kennedy Institute of Ethics and an expert in bioethics, also said the trial’s procedure violates global health standards. 

“If you’re going to be there and put these people in the trials, then you have to give them a standard of care,” Aas told The Hoya. “It would be harder to justify giving something that’s worse than the global standard of care.”

Aside from the ethics of the trial itself, many public health experts contested Kennedy’s decision to hold it in Guinea-Bissau rather than in the United States. 

Emily Mendenhall, a medical humanities and global health expert who also serves as the director of the Science, Technology, and International Affairs program at the School of Foreign Service, commented on the power imbalance in this study. 

“The current administration appears to be employing policy approaches that employ power dynamics that were much more common in colonial times, when the research and trial dynamics relationships where these studies took place were extraordinarily imbalanced,” Mendenhall wrote to The Hoya. 

Mendenhall said outsourcing trials to other countries, especially lower-income, developing countries with vulnerable populations, demonstrates a clear turning point in U.S. government policy.

“Others have argued that this experiment in Guinea-Bissau may mirror the concerns for the Guatemala syphilis study, which mirrored the extraordinarily unethical studies of the Tuskegee experiments,” Mendenhall wrote. 

In both the Guatemala syphilis studies and the U.S.-based Tuskegee experiments, patients were purposefully infected with syphilis, a very dangerous sexually transmitted infection, even after the cure for syphilis had been found. With these and the hepatitis B study, scientists already know the vaccine works, and therefore, bioethicists and medical practitioners believe there is a responsibility to administer it to as many people as possible. 

Oni said it is imperative that children across the world continue to receive this birth-dose vaccine to protect themselves and others.

“Introduction and widespread use of the vaccine has helped keep the incidence rate of infection to less than 1.0 per 100,000 people in the U.S., and we should all do what we can — as students, faculty, citizens — to keep infection rates here low, and bring rates down globally,” Oni said.