Analysis: Time to quit on a Preventive AIDS vaccine?

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Analysis: Time to quit on AIDS vaccine?

By Ed Susman Aug 21, 2006, 18:08 GMT

TORONTO, ON, Canada (UPI) -- For more than 20 years, scientists have

been searching for the vaccine they believe can end the 25-year-old

AIDS pandemic, a worldwide health disaster that has claimed more

than 25 million lives.

As DeAngelis, editor of the Journal of the American

Medical Association, says, 'That landmark means AIDS has taken more

lives than were lost during the bubonic plague of the Middle Ages.'

However, despite the fervent calls for vaccines, the last two

decades have only seen vaccine failures. At the 16th International

AIDS Conference in Toronto last week, the frustration over the lack

of a vaccine let Jules Levin, a long-time AIDS activist, and

executive director and founder of the New York-based National AIDS

Treatment Action Project, to utter what some in the AIDS movement

would call 'heresy.'

'We are not going to find a vaccine for human immunodeficiency virus

(HIV). There will never be an AIDS vaccine,' Levin told United Press

International. 'We are only wasting a lot of resources. It`s time we

stopped spending this money on the vaccine and start looking at

other forms of prevention.'

Heresy, indeed, said another long-term AIDS activist,

Scondras, the Boston, Mass.-based editor of the treatment and action

newsletter 'A Search for the Cure'.

'I don`t think Jules` comments represent what most of us believe. We

cannot give up on a vaccine,' he told UPI. 'Instead, it`s time to

test all these different ideas that people are coming up with all

the time. We don`t need huge cohorts of people to do these tests,

either.'

Scondras said groups of sero-discordant couples could be recruited

to be the test candidates. A sero-discordant couple consists of one

person who, in this context, has been infected with the HIV virus

and a partner who is HIV-negative, or not infected.

Despite the high risk that unprotected sex will eventually result in

transmitting the incurable virus to the other partner, many couples

continue to engage in risky sexual activity. A relatively few of

these couples would be able to determine if a candidate vaccine

worked, Scondras explained.

In a population-based vaccine trial, huge numbers of people at risk

of HIV-infection because they engage in sexual practices that might

bring them in contact with an infected person are required to prove

the effectiveness of the vaccine. The ethics and financial problems

involved in these large scale tests would prohibit testing multiple

candidate vaccines.

Levin may be among the minority of those raising their voices about

whether vaccines should be pursued. However, the fervor for a

vaccine has decidedly diminished.

In his closing remarks to the conference, , the

Canadian diplomat who is the outgoing United Nations special envoy

for HIV/AIDS in Africa, and regarded by many as representative of

the moral center of the AIDS battle, barely mentioned vaccines.

'To be certain, there can be no flagging in the dogged quest for a

vaccine, but it would appear that where preventative technologies

are concerned, the microbicide is first in line,' the silver-tongued

orator said. When that is the only mention of an AIDS vaccine in a

closing speech by , it is obvious that many people are

rethinking the priority of vaccine research.

Lessons learned over the years in vaccine attempts, however, may be

helping scientists construct a vaccine that will work. The virus is

not easily identified as a pathogen by the human immune system and

mounting antibody attacks on the microbe has failed multiple times.

Lara, an AIDS researcher, says the virus avoids detection by

the immune system because it presents decoys to the immune system.

The immune cells in the body attack the decoys, but never are unable

to penetrate the virus itself.

Lara, who works for Biological Mimetics, Inc. in Fredrick, Md., is

trying to devise an antibody that will strip the decoys away from

the virus, exposing it to normal attack by the immune system. He is

still working on animal models of the disease with his 'immune

refocusing' technology, he said during a press briefing at the AIDS

conference, and human studies are still in the future.

Biological Mimetics` vaccine is one of dozens being explored, few of

which are close to large-scale human testing.

The hundreds of millions of dollars being invested in vaccines would

be better diverted to other areas; namely, the low-hanging fruit of

prevention, said Levin. He and Scondras concur that microbicides

that could be used to kill the virus during sexual intercourse is

the best bet to prevent spread of the disease, especially among

women who appear to be disproportionately infected through

heterosexual contacts.

However, even the most optimistic researchers suggest that a

microbicide is still at least five years from the marketplace,

stated.

Another area of prevention involves the use of antiretroviral drugs

such as tenofovir (Viread) that would be taken prior to engaging in

risky sexual activity. Several studies of this 'Pre-Exposure

Prophylaxis (PrEP)' are underway.

But doctors and activists also argue that a vaccine is still needed

because large numbers of women who are raped have no opportunity to

use a microbicide or take the pills in advance of an attack.

Stefano Vella, director of the drug research and evaluation

department of the U.S. National Institutes of Health`s counterpart

in Rome, Italy, the Instituto Superiore di Saniti, was clearly vexed

discussing vaccine development against HIV. 'We clearly do need to

go ahead and find a vaccine,' he told UPI, 'but perhaps we need to

be looking more for a therapeutic vaccine rather than a preventive

vaccine.'

A preventive vaccine -- the form of treatment that is considered the

Holy Grail -- would stop the virus from infecting humans,

effectively ending the epidemic that now affects 38.6 million people

around the globe, mostly in developing countries.

A therapeutic vaccine would help people living with HIV keep the

virus at bay and prevent the microbe from wiping out people`s immune

systems, and subsequently permitting the opportunistic infections --

such as pneumonia, diarrhea and rare cancers -- that are the

hallmarks of AIDS and what actually kills patients.

The therapeutic vaccine, Vella said, would possibly allow people to

be treated with a yearly inoculation instead of daily drug therapy,

a lifelong treatment burden and expense.

'I personally don`t think we are spending enough money on vaccine

development,' said Lieve Fransen, a representative of the European

Commission at the AIDS conference and vice chair of the Global Fund

for the Treatment of AIDS, Tuberculosis and Malaria.

'In my personal opinion, vaccine research has been delayed too

long,' she told UPI. 'If we are really going to break the epidemic

we are going to need a vaccine as well as microbicides. If we as a

society can send a man to the moon, then we must be able to find and

develop a vaccine. We have not spent enough attention on the

vaccine, nor have we spent enough money to find one.'

Copyright 2006 by United Press International

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