The $1.6 million study, 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 widespread criticism due to ethical concerns. Critics argued that the study involved withholding proven hepatitis B vaccines in a nation grappling 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 (WHO), it is a major global health problem, particularly in Africa. The WHO recommends that all infants receive a hepatitis B vaccine as soon as possible after birth, preferably within 24 hours, followed by subsequent doses to ensure full protection.

The ethical concerns surrounding the study centered on the potential harm to newborns who were not immediately vaccinated against hepatitis B as part of the research protocol. Experts argued that withholding a life-saving vaccine, especially in a high-risk region, was unacceptable.

"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 importance of ethical considerations in research.

The cancellation of the study raises questions about the oversight of U.S.-funded research projects in Africa and the need for stricter ethical guidelines. It also highlights the ongoing debate surrounding vaccine hesitancy and the importance of ensuring equitable access to vaccines worldwide. The Africa CDC is now expected to review its protocols for approving and monitoring research projects to prevent similar controversies in the future. The implications of this cancellation for future hepatitis B prevention efforts in Guinea-Bissau are currently unclear.