A recent review of a HIV vaccine trial in Thailand has concluded that it does show real signs of a protective effect.

Last month the scientists announced that a combination of drugs gave a 31% level of protection in trials among 16,000 heterosexuals between the ages of 18-30.

There had been increased doubts about whether the finding would really be effective or not, but new data which was published at a conference in Paris indicates that the findings are string and with solid statistics, though it is still at a small scale.

Scientists are nevertheless, not able to find out why the protection is not effective in those who are at maximum risk and what exactly is causing the effect.

Colonel Nelson Michael from the US military HIV research program said that despite the drawbacks, this is a small step in the right direction.

He said that it was important for people to understand that it was a scientific advance and not a public health breakthrough. He added that it has taken 26 years of struggle to believe that there is a possibility of developing a vaccine which a globally effective.

Although there was an initial wave of joy regarding this finding, many scientists were worried whether the protective effect was very small.

However, after the review has taken place, there are indications that the original findings still hold good.