The project is led by Danish researchers Peter Aaby and Christine Stabell Benn, who have been planning a vaccine trial in the country.
In a Facebook post, the judicial police said the search was meant to clarify the circumstances surrounding the batch, and stressed that the seizure is an investigative step that does not by itself indicate problems with the vaccines' quality, safety, or effectiveness.
According to Ars Technica's reporting, the design could expose thousands of newborns to hepatitis B, risking lifelong infection that can lead to liver cirrhosis, cancer, and premature death.
The US Centers for Disease Control and Prevention announced in December, under Health Secretary Robert F. Kennedy Jr., that it had awarded the researchers an unsolicited $1.6 million grant for the work.
Kennedy, a vaccine skeptic, has repeatedly praised the pair, who claim vaccines cause overlooked harms and are under investigation by Danish authorities for alleged scientific misconduct.
The trial is not currently going ahead. Plans were halted in January after widespread condemnation, and a Rolling Stone report this month said the CDC had set aside another $1.6 million in late September to proceed. Guinea-Bissau's health minister, Quinhin Nantote, said at a press conference that the government has not authorized the study, and that any research involving children must comply with national law, international ethical principles, and formal review and approval. He told the Guardian that reports the trial will move forward are "not even remotely true.
