WHO calls a planned hepatitis B birth-dose trial unethical; Guinea-Bissau has suspended it

The World Health Organization said on 13 February that it has significant concerns about a proposed randomised controlled trial of the hepatitis B birth dose vaccine in Guinea-Bissau, and that in its current form the trial "is inconsistent with established ethical and scientific principles" [s1].

WHO also states that Guinea-Bissau has suspended the study pending further technical reviews [s1].

Statements of this kind from WHO about a specific study are rare. The agency says it acted in response to recent questions from the media, and that its assessment rests on publicly available information about the protocol and consultation with relevant experts [s1].

The design at issue

The trial as publicly described is single-blind with a no-treatment control arm [s1]. That is the element WHO's objection is built around, and its reasoning is set out in five points [s1]:

Proven benefit, foreseeable harm. The hepatitis B birth dose has a safety record across decades of use and is effective in preventing 70–95% of cases of mother-to-child transmission. Withholding it from some participants exposes newborns to serious and potentially irreversible harm, including chronic infection, cirrhosis and liver cancer.

No scientific necessity for a no-treatment arm. Placebo or no-treatment vaccine trials are acceptable only when no proven intervention exists, or when such a design is indispensable to answer a critical efficacy or safety question. WHO says neither condition appears to be met.

Insufficient scientific justification. Publicly available descriptions indicate the protocol does not question the established efficacy and impact of the birth dose; it posits hypothetical safety outcomes without sufficient credible evidence of a safety signal that would warrant exposing participants to risk.

Biased and low-utility design. The single-blind, no-treatment-controlled design raises a significant risk of bias, limiting the interpretability of results and their policy relevance.

Exploiting scarcity is not ethical. Resource constraints cannot justify withholding proven care in research involving people. WHO says the protocol, as publicly described, does not appear to ensure even a minimum level of harm reduction and benefit for participants — for example, screening pregnant women and vaccinating newborns exposed to hepatitis B.

Why the fifth point is the sharpest

The scarcity argument is the one that generalises beyond this trial.

Where a proven intervention is not yet nationally available, it can be argued that a no-treatment arm reflects the local standard of care rather than a withdrawal of something participants would otherwise receive. WHO rejects that framing directly: constraints on resources cannot be used to justify withholding proven care in a study [s1].

This is a long-running fault line in global research ethics, and WHO is stating its position on it in unusually plain terms.

The epidemiology in Guinea-Bissau

The country-specific numbers explain why the stakes are high.

More than 12% of adults in Guinea-Bissau are estimated to be living with chronic hepatitis B, based on 2022 data [s1]. Prevalence in children under five was around 2% in 2020 — far above the global target of 0.1% or less [s1].

Transmission at birth is the most common route to lifelong infection, and around 90% of newborns infected during childbirth become chronic carriers at high risk of cirrhosis and liver cancer [s1]. Hepatitis B causes hundreds of thousands of deaths globally each year [s1].

Guinea-Bissau formally decided in 2024 to add the hepatitis B birth dose to its national schedule, with introduction planned by 2028 [s1]. WHO points to that decision as affirming the vaccine's value in the country's own policy, which it argues underscores the ethical case against withholding protection from newborns in a study [s1].

What WHO is offering instead

The statement pairs the objection with support. WHO says it stands ready to help Guinea-Bissau accelerate introduction of the birth dose and strengthen implementation, specifically through [s1]:

• birth-dose delivery within 24 hours, including strategies for home as well as facility births;
• antenatal screening for hepatitis B surface antigen, linkage to care, and neonatal prophylaxis;
• cold chain, last-mile logistics, and midwife and health-worker training;
• monitoring of timeliness and coverage, pharmacovigilance, and data use for continuous improvement.

The birth dose is used in more than 115 countries' national schedules and has been in use for over three decades [s1].

The limits of what is on the record

WHO's assessment is based on publicly available descriptions of the protocol, a qualification the statement repeats four times [s1]. The full protocol, the sponsoring institutions, the review bodies that approved it and the investigators' own justification are not part of the document, and are not characterised here.

That matters for how much weight the objection can carry on its own. WHO is describing a study as publicly described, not as approved and documented. A fuller judgement depends on material that has not been released.

What is settled is the procedural outcome: the study is suspended pending further technical reviews [s1].

What to watch

Whether Guinea-Bissau's technical review concludes with the trial abandoned, redesigned, or reinstated — and whether the review's reasoning is published.

Whether the sponsors respond with the protocol and its ethical justification. That is the missing half of the record.

And whether the introduction timeline moves. The trial dispute sits on top of a schedule that already places national birth-dose introduction in 2028, four years after the policy decision to adopt it [s1].

Sources

• [s1] World Health Organization, "Statement on the planned hepatitis B birth dose vaccine trial in Guinea-Bissau," 13 February 2026. https://www.who.int/news/item/13-02-2026-statement-on-the-planned-hepatitis-b-birth-dose-vaccine-trial-in-guinea-bissau