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

[Guest guest]

After 25 years and billions of pounds, leading scientists are now

forced to ask this question

By Steve Connor and 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.

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.

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.

At the end of last month, Dr Fauci convened a high-level summit of

leading HIV specialists at a hotel in Bethesda, land, to discuss

the future direction of research. A group of 14 prominent Aids

specialists had already written to Dr Fauci suggesting that his

institute had " lost its way " in terms of an HIV vaccine.

He said that one outcome of the meeting was a refocusing of the

vaccine effort away from expensive clinical trials towards more

fundamental research to understand the basic biology of the virus and

its effects on the human immune system.

" We'll be turning the knob more towards answering some fundamental

questions rather than going into big clinical trials, " Dr Fauci said.

" I'm certainly disappointed that we're not further ahead in the

development of a vaccine but I don't say that this year I'm more

discouraged than I was last year. I always knew from the beginning

that it would be a very difficult task given what we know about this

very elusive virus. "

About 33 million people in the world are infected with HIV and some 26

million have died of Aids since the pandemic began.

The majority of scientists who responded to The Independent's survey

said that a vaccine would be the most effective way of preventing the

spread of the virus given the failure of many education programmes.

Winnie Sseruma, 46: 'For me, the key has been not to give up'

Ms Sseruma says she believes abandoning research for a vaccine would

mean a loss of hope for millions of people. " When I was diagnosed,

nearly 20 years ago, it was when the first drugs had come on the

market. A lot of people had said before then that there was no hope

and that all efforts should be put into prevention. But look where we

are now. We cannot lose hope; we need to invest in a vaccine. "

She says this latest failure needs to be seen as the first hurdle, not

a signal to give up. " Yes, the scientists have not been very

successful in their quest for a vaccine, but you can learn a lot from

failures. Now they have realised they cannot use the normal routes

used to develope simpler vaccines. "

Ms Sseruma lives in London, but was born in Uganda and says that the

current climate of pessimism for the vaccine is not dissimilar to the

initial doubts over the likelihood of treating HIV in Africa.

" I remember when treatment started being available in the West and

people were saying it would be impossible to send it to Africa. But

look what's happened. We should always do whatever is humanly possible

to fight Aids. It's been a long journey, but for me, the key has been

not to give up, and the scientists need to have the same attitude. "

'Philippe B', 42: 'People are getting resistant to drugs'

" Philippe " , who wishes to remain anonymous, discovered he was HIV

positive 11 years ago. The 42-year-old believes the search for the

vaccination should no longer be a priority, but that it should not

stop altogether.

" Unfortunately what's happening now is that people are getting more

resistant to drug treatment, and more money needs to be put into

finding more drugs for treatment, " he said.

For people like Philippe, the fear of building an immunity to drugs

and running out of options is a real one. He believes that as long as

scientists are still pessimistic about the chances of successfully

finding a vaccine, money needs to be invested in continuing to fund

research into treatment.

" I've already become resistant to five combination treatments over the

last ten years, and if I was on the last one available I'd be very

afraid. HIV is not a death sentence in the way it once was, but we do

need to fund further research into the drugs that treat it. "

Nevertheless, Philippe thinks it is not yet time to abandon all

research into a vaccine. " In my lifetime I don't think we'll have a

vaccine, but there's no reason we should believe it isn't possible, "

he said. " But we should now be spending more on other ways of dealing

with the disease. "

http://www.independent.co.uk/news/science/is-it-time-to-give-up-the-search-for-a\

n-aids-vaccine-814737.html