The government of St. Kitts and Nevis has launched an investigation into the clinical trial for a herpes vaccine funded by billionaire and Trump adviser Peter Thiel because its officials were not notified about the experiments. The vaccine research has sparked controversy because lead investigator William Halford of Southern Illinois University and the U.S. company he co-founded, Rational Vaccines, did not rely on traditional U.S. safety oversight while testing the vaccine last year on mostly American participants on the Caribbean island of St. Kitts.

The trial received financial backing from Agustín Fernández III, a former Hollywood filmmaker who has asserted the vaccine was highly successful in stopping herpes outbreaks. Since then, a group of investors, including Thiel, has backed the ongoing vaccine research with a $7 million investment that could include more trials in Mexico and Australia. U.S. researchers, citing rising domestic costs, are increasingly going offshore.

Neither the Food and Drug Administration nor an institutional review board monitored the testing on the 20 human subjects. St. Kitts and Nevis says that the researchers also did not officially seek permission to test the vaccine, which took place from April to August 2016.

"This is a test case," said Bartley Madden, a retired Credit Suisse banker and policy adviser to the conservative Heartland Institute, who is another investor in the vaccine. "The FDA is standing in the way, and Americans are going to hear about this and demand action."

"What they're doing is patently unethical," responded Jonathan Zenilman, chief of Johns Hopkins Bayview Medical Center's Infectious Diseases Division. "There's a reason why researchers rely on these protections. People can die."

A Thiel representative said the billionaire was not available to answer questions by email or in an interview. Thiel, who rose to prominence as co-founder of PayPal, reportedly advised Trump on possible FDA nominees after donating $1.25 million to his presidential campaign. Thiel has been a vocal critic of the FDA, claiming in an interview that its approval process was so unwieldy "you would not be able to invent the polio vaccine today."

— Marisa Taylor, Kaiser Health News