The head of the US agency tasked with controlling the spread of infectious disease on Thursday hailed as an important breakthrough a new AIDS vaccine that reduces the risk of HIV infection by one-third.

“These new findings represent an important step forward in HIV vaccine research,” said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), part of the US National Institutes of Health, which provided major funding and logistical support for the study.

“For the first time, an investigational HIV vaccine has demonstrated some ability to prevent HIV infection among vaccinated individuals,” he said in a statement.

“Additional research is needed to better understand how this vaccine regimen reduced the risk of HIV infection, but certainly this is an encouraging advance for the HIV vaccine field,” he said.

The experimental AIDS vaccine was tested on 16,000 volunteers, the world’s largest medical trial, carried out by the United States Army and Thailand’s Ministry of Public Health.

The vaccine was tested on volunteers — all HIV negative men and women aged from 18 to 30 — at average risk of infection in two Thai provinces near Bangkok starting in October 2003.

Half received the vaccine and the rest were given a placebo. Out of the placebo recipients 74 of 8,198 became infected compared with 51 of 8,197 who got the vaccine.

The breakthrough comes after years of fruitless attempts by the medical world to find an HIV vaccine.

The head of the US agency tasked with controlling the spread of infectious disease on Thursday hailed as an important breakthrough a new AIDS vaccine that reduces the risk of HIV infection by one-third.

“These new findings represent an important step forward in HIV vaccine research,” said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), part of the US National Institutes of Health, which provided major funding and logistical support for the study.

“For the first time, an investigational HIV vaccine has demonstrated some ability to prevent HIV infection among vaccinated individuals,” he said in a statement.

“Additional research is needed to better understand how this vaccine regimen reduced the risk of HIV infection, but certainly this is an encouraging advance for the HIV vaccine field,” he said.

The experimental AIDS vaccine was tested on 16,000 volunteers, the world’s largest medical trial, carried out by the United States Army and Thailand’s Ministry of Public Health.

The vaccine was tested on volunteers — all HIV negative men and women aged from 18 to 30 — at average risk of infection in two Thai provinces near Bangkok starting in October 2003.

Half received the vaccine and the rest were given a placebo. Out of the placebo recipients 74 of 8,198 became infected compared with 51 of 8,197 who got the vaccine.

The breakthrough comes after years of fruitless attempts by the medical world to find an HIV vaccine.