Two AIDS Vaccine Trials Hold Hope Against Epidemic

Twenty-five years into the AIDS epidemic, there's still no vaccine. Some hope is on the horizon but it could take at least 10 more years for any vaccine to enter the market.

At a conference in Toronto that began Sunday, the world's HIV/AIDS groups plan to take stock of the discouraging race between the global medical community and the HIV virus that has killed millions worldwide.

Drug therapy has become a little more accessible, cheaper and easier to take for about 1.1 million people. However, it is still out of reach for most of the world's 40 million people infected with HIV/AIDS.

Stepping into the lurch with increasing promise is the field of topical microbicide gels that could kill the HIV virus in the vagina and protect women from infection.

The wealthy Rockefeller and Bill and Melinda Gates foundations poured start up money into the Maryland-based International Partnership for Microbicides (IPM) several years ago to pursue the idea.

"Now attention is focused on the fact that the epicentre of the epidemic is moving toward poor, married women," IPM spokeswoman Pam Norick said.

Vaccine development has been slow for good reason, according to Larry Corey, principal investigator of HIV Vaccine Trials Network (HVTN) based in Washington.

"The virus is a formidable foe with respect to its ability to change its outer coat, and we still have not learned how to make vaccines that make antibodies," Corey said in Seattle.

The most promising vaccine in three years targets the body's T-cells, and is being developed by Merck pharmaceuticals, according to Wayne Koff, an official at the International AIDS Vaccine Initiative (IAVI), which coordinates a network of global vaccine research projects.

Merck's vaccine, now in the last phase of testing on 3,000 volunteers in South America and the Caribbean, is an improvement over the disappointing Vaxgen that came to a dead end in Thailand in 2003, Koff said.

Tests on the Merck vaccine, delivered to human volunteers using snippets of HIV DNA embedded in a modified common cold virus, could produce final data by 2007, putting it at the top of the pipeline, he said.

A second top candidate comes from the US National Institutes of Health (NIH), HVTN 204, and contains not only a wider variety of DNA from different parts of the virus but also snippets from the three leading global strains of HIV - the first promising candidate to offer such global potential.

It is being tested on 500 volunteers in North and South America, Africa and the Caribbean, vaccine project director Gary Nabel said.

"Realistically, if we have a licensed vaccine in less than 10 years, it would be pretty miraculous," Nabel told DPA.

In addition, a modified version of the Vaxgen trials continues on 16,000 volunteers in Thailand, who are receiving an added T-cell vaccine booster.

A lot depends on money. Global research gets about $800 million a year, an increase over funding levels three years ago but still short of the $1.1 billion needed, IAVI says.

To attract private firms like Merck to the unprofitable field, the US and other governments have provided funds - with the requirement that all results are shared.

For the vast majority of people with HIV, however, Acquired Immune Deficiency Syndrome (AIDS) is still a death sentence.

Only about 10 percent of those infected are aware of it, the Bill Clinton Foundation says, and treatment has fallen far short of the World Health Organization's goal of reaching three million HIV-positive people with life-prolonging medications by 2005.

(Source: IANS)