Is it time to give up the search for an Aids vaccine?

After 25 years and billions of pounds, leading scientists are now forced to ask this question
By Steve Connor and Chris Green
Thursday, 24 April 2008

Most scientists involved in Aids research believe that a vaccine against HIV is further away than ever and some have admitted that effective immunisation against the virus may never be possible, according to an unprecedented poll conducted by The Independent.

A mood of deep pessimism has spread among the international community of Aids scientists after the failure of a trial of a promising vaccine at the end of last year. It just was the latest in a series of setbacks in the 25-year struggle to develop an HIV vaccine.
The Independent's survey of more than 35 leading Aids scientists in Britain and the United States found that just two were now more optimistic about the prospects for an HIV vaccine than they were a year ago; only four said they were more optimistic now than they were five years ago.
Nearly two thirds believed that an HIV vaccine will not be developed within the next 10 years and some of them said that it may take at least 20 more years of research before a vaccine can be used to protect people either from infection or the onset of Aids.
A substantial minority of the scientists admitted that an HIV vaccine may never be developed, and even those who believe that one could appear within the next 10 years added caveats saying that such a vaccine would be unlikely to work as a truly effective prophylactic against infection by the virus.
One of the major conclusions to emerge from the failed clinical trial of the most promising prototype vaccine, manufactured by the drug company Merck, was that an important animal model used for more than a decade, testing HIV vaccines on monkeys before they are used on humans, does not in fact work.
This has meant that prototype HIV vaccines which appear to work well when tested on monkeys infected with an artificial virus do not work when tested on human volunteers at risk of HIV – a finding that will be exploited by anti-vivisectionist campaigners opposed to vaccine experiments on primates.
Anthony Fauci, the director of the US National Institute of Allergy and Infectious Diseases (NIAID), near Washington, told The Independent that the animal model – which uses genetically engineered simian and human immunodeficiency viruses in a combination, known as SHIV – failed to predict what will happen when a prototype vaccine is moved from laboratory monkeys to people. "We've learnt a few important things [from the clinical trial]. We've learnt that one of the animal models, the SHIV model, really doesn't predict very well at all," he said.
"At least we now know that you can get a situation where it looks like you are protecting against SHIV and you're not protecting at all in the human model – that's important," he said.
The NIAID spends about $500m (£250m) on HIV vaccine research each year and despite calls from some Aids pressure groups for funds to be diverted to other forms of Aids prevention, Dr Fauci said this was not the time to stop vaccine research. "I don't think you should say that this is the point where we're going to give up on developing a vaccine. I think you continue given that there are so many unanswered questions to answer," he said. "There is an impression given by some that if you do vaccine research you are neglecting other areas of prevention. That's not the case. We should and we are doing them simultaneously."
More than 80 per cent of the scientists who took part in our survey agreed that it was now important to change the direction of HIV vaccine research, given the failure of the Merck clinical trial, which was cancelled when it emerged that the vaccine may have actually increased the chances of people developing Aids.
Robert Gallo, a prominent Aids researcher in the US who is credited with co-discovering the virus in the early 1980s, likened the vaccine's failure to the Challenger disaster, which forced Nasa to ground the space shuttle fleet for years.
http://www.independent.co.uk/news/sc...ne-814737.html