An experimental AIDS vaccine has for the first time cut the risk of infection, researchers said Thursday, hailing at a medical "breakthrough" in the quarter-century battle against the disease.
The vaccine reduced the risk of being infected by almost a third, they said after the world's largest vaccine trial of more than 16,000 volunteers carried out by the US Army and the Thailand Ministry of Public Health.
"This is a very important scientific advance and gives us hope that a globally effective vaccine may be possible in the future," Colonel Jerome Kim of the US military HIV research programme told a news conference in Bangkok.
"It is the first demonstration that a vaccine against HIV can protect against infection," he said via videolink.
The vaccine was effectively a combination of two older vaccines that had not cut infection on their own. It was tested on volunteers at average risk of HIV infection in two Thai provinces near Bangkok starting in October 2003.
"The outcome represents a breakthrough in HIV vaccine development because for the first time ever there is evidence that HIV vaccine has preventative efficacy," said a statement released by the researchers at a press conference in Bangkok.
"The vaccine has a 31.2 percent efficacy in reducing the risk of HIV infection."