Under Health Secretary Robert F. Kennedy Jr., the CDC announced in December 2025 an unsolicited $1.6 million grant to Danish researchers at the Bandim Health Project in Guinea-Bissau, led by Peter Aaby and Christine Stabell Benn, for a trial that would withhold the hepatitis B birth dose from some newborns, Ars Technica reported. A World Health Organization spokesperson said any study denying the vaccine to participants was “unethical and exposes newborns to serious and potentially irreversible harm,” the Guardian reported. The plans were paused in January after criticism; Rolling Stone reported, citing unnamed sources, that in late September the CDC director's office had another $1.6 million set aside to move forward.
On October 19, Guinea-Bissau's judicial police searched the project's offices and seized the vaccine doses, saying the seizure did not point to “irregularities in the quality, safety, or effectiveness of the vaccines.” On October 21 the lead researcher wrote that the study “will not move forward in Guinea-Bissau,” the Guardian reported. No infants were enrolled.