WHO Raises Ethical Concerns Over Hepatitis B Vaccine Trial

Based on publicly available information and expert consultations, WHO said the trial appears inconsistent with core ethical standards.

The World Health Organization (WHO) has reaffirmed that the hepatitis B birth dose vaccine is a proven, life-saving public health intervention and raised serious ethical and scientific concerns about a proposed randomized controlled trial (RCT) in Guinea-Bissau that would withhold the vaccine from some newborns.

The birth dose vaccine — administered within 24 hours of birth — prevents 70–95% of mother-to-child transmission of hepatitis B, a leading cause of chronic liver disease, cirrhosis and liver cancer. Used for more than three decades and included in national immunization schedules in over 115 countries, the vaccine is widely recognized as central to global hepatitis elimination efforts.

WHO Questions Scientific and Ethical Basis of Proposed Trial

In response to media inquiries, WHO said it has “significant concerns” regarding the proposed study’s scientific justification, ethical safeguards, and compliance with established principles governing research involving human participants.

Based on publicly available information and expert consultations, WHO said the trial appears inconsistent with core ethical standards.

Why Withholding a Proven Vaccine Raises Ethical Red Flags

WHO outlined several key concerns:

Proven benefit, foreseeable harmThe hepatitis B birth dose has a long-standing safety record and is highly effective. Withholding a proven life-saving intervention exposes newborns to preventable risks, including chronic infection, cirrhosis, and liver cancer — conditions that can have irreversible, lifelong consequences.

No scientific necessity for a no-treatment armPlacebo or no-treatment trials are only ethically permissible when no proven intervention exists or when such a design is indispensable to answer a critical question of safety or efficacy. WHO noted that neither condition appears to apply in this case.

Insufficient justification for safety concernsPublic descriptions of the protocol reportedly focus on hypothetical safety outcomes without credible evidence of a safety signal that would justify exposing participants to avoidable harm.

Design limitations and risk of biasThe proposed single-blind, no-treatment-controlled design raises a substantial risk of bias, potentially limiting the interpretability and policy relevance of the findings.

Scarcity does not justify withholding careWHO emphasized that resource constraints cannot ethically justify withholding proven care in a research setting. Ethical research must minimize risk and ensure a prospect of benefit to participants. Publicly described aspects of the protocol do not appear to include sufficient harm-reduction measures, such as screening pregnant women or vaccinating exposed newborns.

“In its current form, and based on publicly available information, the trial is inconsistent with established ethical and scientific principles,” WHO stated.

Study Suspended Pending Review

WHO confirmed it is aware that Guinea-Bissau has suspended the trial pending further technical review. The agency said it stands ready to support national authorities as they consider next steps.

Accelerating Protection for Newborns

WHO reiterated its commitment to helping Guinea-Bissau strengthen implementation of the hepatitis B birth dose through:

• Ensuring vaccination within 24 hours of birth, including for home and facility deliveries

• Antenatal screening for hepatitis B surface antigen (HBsAg), linkage to care, and neonatal prophylaxis

• Strengthening cold-chain systems, last-mile logistics, and healthcare worker training

• Monitoring timeliness and coverage, pharmacovigilance, and data-driven quality improvement

Commitment to Global Elimination

Hepatitis B remains a major global health threat, with mother-to-child transmission accounting for a significant proportion of chronic infections worldwide. Timely birth dose vaccination is considered one of the most cost-effective and impactful tools in the fight against viral hepatitis.

WHO reaffirmed its commitment to working with governments, researchers, and partners to ensure that all newborns — in Guinea-Bissau and globally — receive timely, evidence-based protection and that research in this field adheres to the highest ethical and scientific standards.