At least 83 people died as human guinea pigs in macabre US research on sexually transmitted diseases in Guatemala in the 1940s, a commission ordered by President Barack Obama concluded.
Nearly 5,500 people were subjected to diagnostic testing and more than 1,300 were exposed to venereal diseases by human contact or inoculations in research meant to test the drug penicillin, the presidential commission found.
Within that group, "we believe that there were 83 deaths," said Stephen Hauser a member of the commission, which has pored over 125,000 documents linked to the shocking episode since being set up by Obama last November.
Among the 1,300 people exposed to STDs during research between 1946 and 1948, "under 700 received some form of treatment as best as could be documented," Hauser said.
Obama personally apologized to Guatemalan President Alvaro Colom in October before ordering a thorough review of what happened. Secretary of State Hillary Clinton described the experiments as "clearly unethical."
This sentiment was clearly expressed by the commission, which said US government researchers must have known they were contravening ethical standards by deliberately infecting mental patients with syphilis.
Commission president Amy Gutmann called it an "historic injustice," and said the inquiry aimed to "honor the victims and make sure it never happens again."
"It was not an accident that this happened in Guatemala," Gutmann said. "Some of the people involved said we could not do this in our own country."
The US researchers "systematically failed to act in accordance with minimal respect for human rights and morality in the conduct of research," she said, citing "substantial evidence" of an attempted cover-up.
A Guatemalan study, which was never published, came to light in 2010 after Wellesley College professor Susan Reverby stumbled upon archived documents outlining the experiment led by controversial US doctor John Cutler.
Cutler and his fellow researchers enrolled 1,500 people in Guatemala, including mental patients, for the study, which aimed to find out if penicillin could be used to prevent sexually transmitted diseases.
Initially, the researchers infected female Guatemalan commercial sex workers with gonorrhea or syphilis, and then encouraged them to have unprotected sex with soldiers or prison inmates.
Neither were the subjects told what the purpose of the research was nor were they warned of its potentially fatal consequences.
Cutler, who died in 2003, was also involved in a highly controversial study known as the Tuskegee Experiment in which hundreds of African-American men with late-stage syphilis were observed but given no treatment between 1932 and 1972.
The Guatemalan president has called the 1946-1948 experiments conducted by the US National Institutes of Health "crimes against humanity" and ordered his own investigation.