The $1.6 million project, funded under the purview of Robert F. Kennedy Jr., a known vaccine skeptic, and the U.S. Department of Health and Human Services (HHS), sparked outrage for its approach of withholding proven hepatitis B vaccines in a region with a high prevalence of the disease. Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic disease. According to the World Health Organization, the virus is most commonly spread from mother to child during birth and delivery, as well as through contact with infected blood or other body fluids.

The core ethical issue revolved around the potential harm to newborns who were not immediately vaccinated against hepatitis B as part of the study's protocol. Standard medical practice in most parts of the world, including recommendations from the WHO and the U.S. CDC, is to administer the hepatitis B vaccine within 24 hours of birth to prevent chronic infection.

"It’s of importance for Africa CDC to have evidence that can be translated in policy, but this has to be done within the norm," Boum stated, emphasizing the need for ethical research practices.

The study's cancellation raises questions about the oversight of international research projects, particularly those involving vulnerable populations. The Africa CDC's intervention highlights the growing emphasis on ethical research conduct and the protection of participants in clinical trials conducted in Africa. The cancellation also underscores the importance of aligning research initiatives with established public health guidelines and ethical standards. Further details regarding the specific design of the study and the rationale behind the initial decision to proceed with it have not been fully disclosed. It remains unclear what will happen to the data collected thus far, and whether any alternative studies will be conducted to address hepatitis B prevention in Guinea-Bissau.