HIV vaccine cuts infection risk by a third

Published on Thursday 24 September 2009 22:13

AN EXPERIMENTAL HIV vaccine has been shown to reduce the risk of the infection for the first time, it was announced yesterday.

In a major breakthrough in the fight against the deadly illness, researchers found the vaccine cut the risk of becoming infected with HIV by more than 31 per cent.

The results of the study – the world's largest Aids trial of more than 16,000 volunteers in Thailand – was welcomed around the globe. The World Health Organisation and the UN agency UNAids said the results "instilled new hope" in the field of HIV vaccine research.

In the UK, experts said the outcome would be a "real boost" at a time when some were questioning whether a vaccine against the virus would ever be possible.

Colonel Jerome Kim, who helped lead the study for the US army, said even though the benefit was modest "it's the first evidence that we could have a safe and effective preventive vaccine".

Dr Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, which also sponsored the trial, warned that this was "not the end of the road," but said he was surprised and very pleased at the outcome.

The Thailand Ministry of Public Health conducted the study using strains of HIV common in the country. It is unclear if such a vaccine would work against other strains in the US, Africa or elsewhere in the world.

But even a marginally helpful vaccine could have a big impact. Every day, 7,500 people worldwide are infected with HIV. In 2007, two million died of Aids.

The study tested two different vaccines used in combination, ALVAC and AidsVAX.

Neither of the vaccines prevented HIV infection when tested individually in earlier trials.

The study tested the vaccines in Thai men and women aged 18 to 30 at average risk of becoming infected with HIV.

All were given condoms, counselling and treatment for any sexually transmitted infections, and were tested every six months for HIV. Any who became infected were given free treatment with antiviral medicines.

Participants were followed for three years after vaccination ended.

New infections occurred in 51 of the 8,197 given the vaccine and in 74 of the 8,198 who received dummy shots – a 31 per cent lower risk of infection for the vaccine group.

In the UK, researchers welcomed the results. Robin Shattock, professor of cellular and molecular infection at St George's, University of London, said: "This trial is very promising.

It gives researchers a real boost at a time when some were questioning whether a vaccine would ever be possible."

Lisa Power, the head of policy at the Terrence Higgins Trust, said: "This is very good news for the future."