Friday, 25 September 2009

A breakthrough HIV vaccine?

Over the last couple of days the media has been full of stories reporting the results of a HIV vaccine trial, purporting to be the first ever to show that such a vaccine is both possible and safe. Although the reported efficiency of the vaccine in preventing HIV infection is just 31%, it is being portrayed as a major breakthrough given that all the other candidates so far developed have been unsuccessful. It does indeed sound like a huge step forward; one that is much needed given the ever-increasing number of people affected by the virus. However, my suspicions were stirred when I saw the numbers involved: out of a group of 8197 given the vaccine 51 people became infected over the three-year trial period, whereas out of a group of 8198 given a placebo 74 became HIV-positive. These numbers are small. It was claimed that the results were still statistically significant, but not being one to take media science stories at face value, I wanted to check for myself. My mind was full of questions: how did the people in the two groups compare, how were they chosen, were the ones who became infected simply at a higher risk than the others? The research paper would surely give me these answers.

Except that it didn't. Why? Because it doesn't even exist yet. All these articles in the media have been produced off the back of a press release, a document produced by the division of the US military running the trial which of course has an interest in the favourable dissemination of the results. Nothing has yet been peer-reviewed, there is no way for anyone interested to make their own interpretation of the results, to banish any suspicions they may have.

So why did they issue the press release this week? Why not let the story break on the same day as the full results are published in a reputable journal? The vaccine isn't going to save thousands of lives imminently, so it hardly matters if the news comes out today or in a week’s time. It is perfectly possible to let journalists know about the story beforehand, so that they can get their story prepared, but have them agree to only publish it at the same time as the scientific article comes out; this kind of arrangement happens all the time. Why didn't it in this case? The cynic in me wonders what they had to hide, and so I automatically become less trusting of the results.

I truly hope that it was a very carefully controlled study, that the results are reliable and that it really does herald a new leap forward in the worldwide fight against HIV. Other things about the trial which make me uncomfortable (such as the fact that it was run by the US military but carried out on people from Thailand) may well prove to have very reasonable explanations. It's just that without being able to see the evidence myself, I don't know, fellow scientists don't know, and the journalists certainly don't know, and that is a bad situation for all concerned.

Read the press release

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