A planned vaccine trial on 14,000 newborns in Guinea-Bissau has ignited international controversy, exposing questions about medical ethics, colonial-era research practices and the influence of vaccine skepticism in global health policy.
The West African nation suspended the U.S.-funded hepatitis B study Jan. 22 following widespread condemnation from health experts who argued the trial would deliberately withhold lifesaving vaccines from half the participants. The decision came after researchers from Denmark’s University of Southern Denmark had already secured $1.6 million in funding from the U.S. Centers for Disease Control and Prevention under the leadership of Robert F. Kennedy Jr., a prominent vaccine skeptic.
The controversy highlights growing tensions over how medical research is conducted in developing nations and who bears the risks when Western institutions test theories that would face stricter scrutiny in their home countries.
“I was disappointed, to say the least, that my country could have approved a study of that kind,” said Magda Robalo, Guinea-Bissau’s former health minister and a veteran World Health Organization official, speaking from the capital, Bissau.
The Study Design and Its Critics
The trial proposed dividing 14,000 infants into two groups. Half would receive the hepatitis B vaccine at birth, following WHO recommendations. The other half would wait six weeks — Guinea-Bissau’s current practice due to vaccine shortages — before receiving their first dose. Researchers would then track health outcomes over five years.
Hepatitis B poses severe risks to infants. The virus, which spreads through bodily fluids and is often transmitted from infected mothers during childbirth or breastfeeding, can cause chronic infection in babies whose immune systems are too weak to fight it off. Long-term consequences include liver damage and cancer. The disease killed 1.1 million people globally in 2022, according to WHO data.
While no cure exists, WHO-approved vaccines administered at birth offer protection that can last a lifetime, according to numerous independent studies. Guinea-Bissau, where one in five people carries the virus — among the world’s highest infection rates — currently vaccinates infants at six weeks due to limited supplies. The country plans to shift to birth-dose vaccination by 2028.
Danish researchers argued their study was timely, capitalizing on the remaining years before Guinea-Bissau changes its vaccination schedule. They emphasized that half the participants would receive birth doses for the first time in the country’s history.
But critics called the design fundamentally unethical. “You don’t run such research,” Robalo said. “It is unethical to deny children an intervention that we know works, that will contribute to improving their lives and save them from a disease that we know they will likely acquire.”
Robalo and other experts noted that while Guinea-Bissau’s national ethics committee knew about the study, the country’s public health institute — which would typically review such significant research — was never informed. She suggested the approval process exploited the nation’s limited research infrastructure.
“They took advantage of the fact that Guinea-Bissau does not have a very strong research capacity … a very strong critical mass of public health professionals, very well versed in understanding what the politics that surround global health are,” she said.
Researchers Under Scrutiny
The trial was designed by scientists at the Bandim Health Project, affiliated with the University of Southern Denmark, which has conducted research in Guinea-Bissau since 1978. The project is chaired by Christine Stabell Benn, with founder Peter Aaby. Both are prominent Danish scientists who say their work examines vaccines’ unintended effects.
The married couple has faced persistent criticism from fellow scientists. Their research has suggested that vaccines containing inactivated viruses — including those for diphtheria, tetanus and pertussis, as well as hepatitis B — may cause adverse reactions, including increased mortality. But critics say their claims lack solid evidence.
One of their studies concluded the DTP vaccine was linked to higher child mortality, particularly among girls. After reviewing the findings in 2014, WHO found the results inconsistent but warranting further examination. The organization recommended countries continue DTP vaccination.
Last February, Danish publication Weekendavisen revealed the researchers had not published results from a randomized controlled trial they conducted 14 years earlier examining DTP vaccine effects. The study, which hypothesized the vaccine increased child mortality especially among girls, showed null results — no significant effects. Yet the pair continued conducting related studies and publicly questioning the vaccine’s safety, the newspaper reported. The study was published months after the investigation.
Benn defended their record, telling news organizations that accusations raised in Danish newspapers were investigated by their institution’s research integrity committee, which found no grounds for sanctions.
But Anders Peter Hviid, a researcher at Denmark’s State Serum Institute, questioned the researchers’ fundamental approach. “They haven’t really been able to produce solid evidence to back these hypotheses up,” he said, adding: “They have a lot of null findings which they keep ignoring themselves, time and again … and they are overlooking these ethical issues and basically running trials that are negative again and again and again on African children.”
Additional concerns emerged about the Guinea-Bissau trial’s methodology. Critics noted that hepatitis B infections in newborns can manifest decades after the proposed five-year study period, meaning full effects of delayed vaccination might never be documented. The researchers also planned an “open-label” design, where organizers would know which participants received vaccines — a departure from standard “blind” protocols designed to prevent bias.
In a lengthy statement, Benn and Aaby pushed back against what they called “moral outrage,” arguing critics lacked a “curious and humble” mindset. They insisted they weren’t questioning vaccine effectiveness but examining whether “the prevention comes at a prohibitive price,” such as death.
“The moral outrage from academic celebrities seems unnecessary,” they wrote. “Contrary to what some of the critiques claim, we will not withhold the vaccination from any children who would otherwise have received it … As a result of the trial, more children who would not otherwise have had it, are actually getting the vaccine.”
The Kennedy Connection and Policy Shifts
Despite facing controversy in Denmark, the Bandim Health Project found support from the U.S. Centers for Disease Control under Kennedy, a longtime vaccine skeptic whose advocacy group praised Aaby in a 2019 article.
The researchers secured their $1.6 million grant in December through an expedited process that bypassed the competitive, rigorous review typically required for human subject research and CDC monitoring. This occurred after Kennedy disbanded a team of senior scientists at the agency and appointed a non-scientist as acting director.
Kennedy has long promoted claims linking vaccines to autism, assertions repeatedly debunked by scientific research. Details leaked online about the Guinea-Bissau study showed it specifically aimed to investigate whether birth-dose hepatitis B vaccination could lead to skin disorders and neurodevelopmental conditions, including autism, by age five. In December, WHO reaffirmed no link exists between vaccines and autism.
When news of the trial drew attention from researchers in Denmark and the United States in early January, Guinea-Bissau consulted the Africa Centres for Disease Control and Prevention, which said the study required review. U.S. health department officials repeatedly told reporters the experiment would proceed, creating confusion before Guinea-Bissau’s government suspended it Jan. 22.
A November military coup had installed a new government in Guinea-Bissau. Health Minister Quinhin Nantote confirmed last week his administration had not participated in discussions about the study.
The CDC told news agencies the experiment was important for testing “non-specific effects” of hepatitis B vaccine. The agency did not respond to requests for additional comment.
Under Kennedy’s leadership, the U.S. has suspended funding to Gavi, the Vaccine Alliance, which helped deliver critical doses to lower-income nations during the COVID-19 pandemic. In justifying the cuts to Gavi, Kennedy cited the Bandim Health Project’s work.
The U.S. has also reduced recommended vaccines for newborns from 17 to 11. In December, the health department eliminated a decades-old recommendation that infants receive hepatitis B vaccines at birth, instead advising that guardians and physicians decide for themselves.
Echoes of Past Medical Ethics Violations
For many observers, the controversy evokes painful memories of Western-led medical studies that harmed vulnerable populations.
During a 1996 meningitis outbreak in Nigeria’s Kano State, Pfizer administered experimental antibiotic Trovan to 200 children. The drug, not approved by the U.S. Food and Drug Administration, caused severe reactions. At least 11 children died, while others suffered injuries ranging from paralysis to blindness. The incident fueled vaccine mistrust that persists in northern Nigeria. In 2003, widespread boycotts of a polio vaccination campaign led to an outbreak that saw Nigeria account for approximately 80% of global polio cases the following year. COVID-19 vaccine campaigns faced similar hesitancy in the region.
An earlier case in the United States saw health authorities study untreated syphilis in approximately 400 Black men in Tuskegee, Alabama, from 1932 to 1972. Researchers observed the men through death despite effective treatments like penicillin becoming available. More than 100 men died during the trial.
These historical violations of medical ethics have left lasting scars on communities’ trust in public health institutions and made contemporary research practices subject to heightened scrutiny.
Guinea-Bissau Charts Its Own Course
Back in Bissau, Robalo emphasized that Guinea-Bissau’s priority should not be retesting a proven vaccine but securing adequate supplies for birth-dose administration.
After nearly five decades operating in Guinea-Bissau, the Bandim Health Project should have known which agencies to consult, particularly following November’s military coup, she said. The researchers should also have trained sufficient numbers of Bissau-Guinean scientists in clinical research to strengthen local capacity.
“We are not second-level citizens,” Robalo said. “We are not a population to be used for anything that you cannot do in the Global North. We demand respect, despite the fact that we don’t have the capacity that we need. We don’t tolerate that.”
The suspension reflects broader questions about power dynamics in international health research. As developing nations strengthen their scientific infrastructure and assert greater sovereignty over research conducted within their borders, the era of Western institutions conducting controversial studies with limited local oversight may be drawing to a close.
For Guinea-Bissau’s 2.2 million people — one-fifth of whom carry hepatitis B — the immediate challenge remains clear: securing enough vaccine doses to protect every newborn from a preventable disease, rather than becoming test subjects in a debate that has already been settled by medical science.
The study’s suspension leaves 14,000 families who might have participated facing the same shortage that has defined Guinea-Bissau’s vaccination program for years. But it also sends a message that the country will not compromise its children’s health to validate theories that mainstream science has repeatedly examined and found wanting.
