A controversial US-backed hepatitis B vaccine trial intended for newborns in Guinea-Bissau has been halted, with the lead researcher stating that the necessary governmental approval was not obtained. The study, which had drawn significant global criticism, will not proceed in the West African nation.

Frederik Schaltz-Buchholzer, a Danish researcher involved in the project, announced the halt on Wednesday, indicating that the study "will not move forward in Guinea-Bissau" because "we were not given the necessary governmental approval." This development follows prior statements from Guinea-Bissau's Minister of Health, Quinhin Nantote, who had denied that the project would proceed.

The proposed trial was set to receive substantial funding, with $1.6 million earmarked from the US Centers for Disease Control and Prevention (CDC) and an additional $1.6 million from private entities, including the Bill Ackman-backed Pershing Square Foundation and the Bluebell Foundation. Critics, such as Paul Offit, a vaccines expert at the Children’s Hospital of Philadelphia, had previously labeled the study as unethical.

Authorities in Guinea-Bissau have taken control of the vaccines intended for the trial. The Minister of Health's office reportedly apprehended the vaccines after searching the offices of the Bandim Health Project on Monday. Offit suggested that the seized funds could instead be used to accelerate existing vaccination programs for children in the country.

Guinea-Bissau currently has plans to implement a universal birth dose of hepatitis B vaccine in 2028. The researchers, including Schaltz-Buchholzer, Christine Stabell Benn, and Peter Aaby, were investigating the potential mortality benefits of live vaccines like BCG, and how co-administration with other vaccines, such as hepatitis B, might affect these benefits.

This research aimed to explore a hypothesis that certain live vaccines may offer broader mortality advantages beyond their specific disease prevention. The researchers were interested in whether giving the hepatitis B vaccine concurrently with a live vaccine could potentially diminish these broader benefits.

The controversy surrounding the trial highlighted ethical debates regarding vaccine research, particularly in vulnerable populations. Questions were raised about the informed consent process and the potential for unintended consequences of the research design.

The halt of this specific trial leaves unresolved questions about the future of similar research and the broader implications for public health initiatives in Guinea-Bissau and other developing nations. The focus now shifts to how the country will proceed with its existing plans for newborn hepatitis B vaccination.