WASHINGTON — Defying U.S. safety protections for human trials, an American university and a group of wealthy libertarians, including a prominent Donald Trump supporter, are backing the offshore testing of an experimental herpes vaccine.

The American businessmen, including Trump adviser Peter Thiel, invested $7 million in the ongoing vaccine research, according to the U.S. company behind it. Southern Illinois University also trumpeted the research and the study’s lead researcher, even though he did not rely on traditional U.S. safety oversight in the first trial, held on the Caribbean island of St. Kitts.