US-funded hepatitis B trial in Guinea-Bissau is unethical: WHO

The World Health Organization (WHO) has issued a sharp rebuke against a now-suspended medical trial in Guinea-Bissau, labeling the United States-funded study into hepatitis B vaccines as unethical. The research, which aimed to involve 14,000 newborns, faced intense scrutiny for potentially exposing infants to irreversible harm by withholding a proven life-saving intervention.

Controversial research design

The study, led by Danish researchers and backed by the U.S. Department of Health and Human Services (HHS), proposed a split-group approach. One group of infants would receive the hepatitis B vaccine at birth, while the other would have the shot delayed until they were six weeks old.

On February 13, 2026, the WHO stepped in, citing significant concerns regarding the study’s scientific justification and ethical safeguards. According to the global health body:

• Proven Record: The birth-dose vaccine has been a standard public health tool for over 30 years in more than 115 countries.
• Transmission Risk: In Guinea-Bissau, where chronic hepatitis B affects an estimated 12% to 20% of adults, birth-dose vaccination is 70-95% effective at preventing mother-to-child transmission.
• Standard of Care: The WHO maintains that placebo-style trials are only acceptable when no established treatment exists—which is not the case here.

Political undertones and local backlash

The trial emerged under the leadership of U.S. health secretary Robert F. Kennedy Jr., who has frequently voiced skepticism regarding vaccine safety. Recently, a HHS-appointed advisory panel he restructured voted to end the recommendation that all US newborns receive the hepatitis B jab.

In Guinea-Bissau, the project sparked immediate public outrage. Critics and local leaders questioned why West African infants were being used to test theories already dismissed by mainstream science.

“It’s not acceptable and it should not go on,” Guinea-Bissau’s former health minister Magda Robalo told Nature. “Guinea-Bissauans are not guinea pigs.”

The danger of delayed vaccination

While Guinea-Bissau currently administers the vaccine at six weeks, the government had already been working with the WHO to move that timeline to within 24 hours of birth by 2028. The WHO warned that 90% of newborns infected at birth become chronic carriers, facing high lifelong risks of cirrhosis and liver cancer.

Following the backlash and the WHO’s intervention, the Guinea-Bissauan government suspended the project in January 2026.