SO, now we have a vaccine that seems to protect people against HIV 鈥� but don鈥檛 pop any champagne corks just yet. The victory was won by the slenderest of numerical margins, and we won鈥檛 know whether the vaccine genuinely worked until all the details have been picked over.
The answer is critical to HIV vaccine development, because the favourable result last week was the first vaccine home run against HIV following the failures of earlier candidates in 2003 and 2007. The hordes of researchers who wondered whether a vaccine would ever work now seem to have had their prayers answered by , a trial in 16,000 volunteers in Thailand, coordinated and funded by the and run by the Thai Ministry of Public 午夜福利1000集合.
What was that the vaccine, a combination of two components called Alvac and Aidsvax, appears to reduce the risk of HIV infection by 31.2 per cent. But a closer look at the data shows how slender the margin was between success and failure.
Advertisement
Of the 8197 people who were given the vaccine, 51 picked up infections with HIV nevertheless. This is only marginally fewer than the 74 who became infected after receiving a placebo instead of the vaccine, out of the 8198 volunteers who were treated in this way.
鈥淚f just 11 participants switched from one group to the other, the two groups would have been equal,鈥� says of Weill Cornell Medical College in New York. He fears that when the results are fully analysed, the result may not stand. 鈥淚鈥檓 going to reserve judgement until we see the full data,鈥� he says.
Moore says early disclosure of raw data has proved unwise in the past. The trial results of the most recent vaccine failure, the so-called STEP trial in 2007, at first seemed to show that not only did the vaccine fail to protect, but it made recipients more, not less, prone to infection. 鈥淭he result was not just bad, it was devastating,鈥� says Moore. But subsequent analyses showed that the vaccine did not in fact increase the risk of infection.
鈥淭he STEP trial analogy is a good one,鈥� says Moore. 鈥淭he initial reaction was a reaction to the raw numbers, and it turned out to be misleading.鈥�
The US Military HIV Research Program (MHRP), which coordinated the trial, says that despite the small numbers involved, the result is robust. The supporting data will be disclosed in full next month at the in Paris, France.
So why did the MHRP give only a partial story last week? The result was disclosed at the earliest available opportunity at the request of the Thai collaborators, says Merlin Robb, deputy director for clinical research at the MHRP.
鈥淭he Thai Ministry of Public 午夜福利1000集合 was very anxious to let the volunteers in Thailand know the result as soon as possible, instead of waiting for a scientific conference,鈥� says Robb. 鈥淭his reflects our commitment to the volunteers and transparency in all aspects of this trial,鈥� he said.
Robb says that a manuscript has been prepared and will be submitted shortly for peer review and publication. 鈥淲e鈥檙e committed to disclosing all of the information as quickly as possible.鈥�
The results are likely to get a full house at the Paris meeting, as everyone New Scientist contacted said that the priority is to analyse the data fully and find out how the vaccine worked.