Global health ethics in international collaborative research during policy transition: what can we learn from the proposed newborn hepatitis B vaccine trial in Guinea-Bissau?

International collaborative research in Africa has raised ethical challenges for decades. The proposed newborn hepatitis B vaccine trial in Guinea-Bissau is the latest case to crystallise concerns around potential exploitation of disadvantaged populations, drawing comparisons to Tuskegee and other research abuses. We argue that the decision to stop the trial was appropriate, but that the reasons most invoked in public debate are incomplete. The trial was designed to happen during a defined window before Guinea-Bissau's planned rollout of the universal birth-dose vaccination in 2027-28, when randomisation between the WHO-recommended birth dose and the existing local standard of care remained possible. Under what conditions, if any, could such research-comparing a local versus global standard of care during health policy transition-be ethically justified? We propose four conditions and assess the proposed trial against them. The trial potentially satisfies some of our proposed conditions but does not meet others owing to an absence of maternal hepatitis B screening despite high background prevalence, methodological shortcomings that threaten the interpretability of results, and governance deficiencies, including an absence of sponsor-country ethics review (required by the Declaration of Helsinki). We treat this trial as a cautionary tale offering important lessons for future research in low-resource settings undergoing policy transitions.