US government scientists who infected Guatemalans with syphilis and gonorrhoea as part of a study knew they were violating ethical rules, a US presidential panel has said. The researchers infected hundreds of prisoners, psychiatric patients and sex workers during the 1940s to study the effects of penicillin.
None of the Guatemalans was informed. But many of the same scientists had sought consent from participants in an earlier study in the US.
Dr Amy Gutmann, head of the Presidential Commission for the Study of Bioethical Issues, called the research a "shameful piece of medical history".
"It is important that we accurately document this clearly unethical historical injustice. We do this to honour the victims," she said in a statement.
Guatemala's Vice President Rafael Espada told the BBC that his government would make a formal apology to the Guatemalan people as local doctors had also been involved in the US-funded programme.
The Commission said some 5,500 Guatemalans were involved in all the research that took place between 1946 and 1948. Of these, some 1,300 were deliberately infected with syphilis, gonorrhoea or another sexually transmitted disease, chancroid.
And of that group only about 700 received some sort of treatment.
According to documents the commission had studied, at least 83 of the 5,500 subjects had died by the end of 1953.