Reality Check

Women and HIV: The promise of microbicides

CBC News Online | Aug. 10, 2006

According to the World Health Organization, women account for nearly 70 per cent of HIV-AIDS cases worldwide.
» In Depth: AIDS

When most people think about AIDS, they see it primarily as a problem of the gay community or of those who share needles. And they wouldn't be wrong.

But over the past half-dozen or so years, the face of AIDS in Canada and the United States has begun to change quite dramatically. More and more of those acquiring the disease turn out to be young heterosexual women, infected by their partners.

As the Public Health Agency of Canada reported just last month, women now make up 20 per cent of the approximately 58,000 Canadians infected with HIV, up from 14 per cent in 2002.

What is more alarming is the quick step of this trend. In the late 1990s, getting AIDS from straight sex in Canada was a fairly rare occurrence. Fewer than 11 per cent of all new adult cases before 1998 stemmed from heterosexual sex, according to health officials. Today that proportion has nearly tripled and young, straight women alone accounted for 27 per cent of all new infections last year — a huge jump.

Seen another way, Canada's experience might be said to mirror that of some of the worst parts of Africa where the AIDS virus first rampaged through the male population but now seems to be turning its bile much more toward women.

According to the World Health Organization, women account for nearly 70 per cent of HIV-AIDS cases worldwide and in places such as sub-Saharan Africa and India a growing numbers are married women infected by their husbands, with little power to do much about it.

A tool for women

This feminization of HIV is certain to be a dominant theme at the 16th International AIDS Conference being held Aug. 13 to 18 in Toronto, with nearly 20,000 delegates from around the world.

Until fairly recently, no one expected that marriage and motherhood might be the ingredients for an HIV time bomb. But with vaccines probably a decade or more away and condoms, the best protection, caught up in the abstinence demands of the religious right and the power relationship of the marriage bed, salvation is being sought in the form of a virus-killing vaginal gel called a microbicide.

According to WHO, there are now 23 microbicide gels or creams in different stages of clinical development. Five, including one of the earliest products, Carraguard (made from seaweed), are in the midst of large Phase III trials involving tens of thousands of women in at least seven African countries and India.

This means they might be available for the general population within three or four years if they are proven to be effective. One of the five is a Canadian product, Ushercell, from a small Toronto-based company, Polydex Pharmaceuticals.

Because these scientific trials are still going on, companies involved can't talk about how their products are performing. But that won't stop microbicides from taking centre stage at the AIDS conference. They have a number of important backers such as Canada's Stephen Lewis, the UN's special envoy for HIV/AIDS; Bill and Melinda Gates, whose foundation has spent billions on the AIDS fight; and any number of international agencies.

Microbicides work in different ways. Some provide a physical barrier to keep HIV and (it is hoped) other sexually transmitted viruses from attaching to vaginal walls. Some boost natural vaginal defences by manipulating the acidic PH factor. Newer ones are based on antiretroviral therapies and try to strip the invading virus of its protective coatings and grappling bits.

Their best features, however, are that they are relatively inexpensive, easy to manufacture and distribute in jars and squeeze tubes and, most importantly, as WHO points out, can be applied by women without the co-operation, consent or even knowledge of their partners.

In the sneaky world of marital sex, this is a definite power-changer for those who might lack the confidence or social skills to negotiate condom use.

The drawbacks

One of the biggest drawbacks when it comes to microbicides is that they are not being advanced by any of the world's larger pharmaceutical companies, which in the end may be more an indictment of their social consciences and how little they care about markets in developing countries.

This wouldn't be so bad except that these companies can bring considerable resources to the research table. Now pro-microbicide AIDS groups are coming to Toronto pleading for an immediate doubling in public funds, from $160-million to $320-million annually, just to keep the research pipeline moving. (Canada has been a modest contributor to these projects, about $15 million a year, but that is soon to run out. The U.S. government, the Brits and the Gates Foundation have been by far the biggest supporters.)

Another drawback is that no one seems to really know the effect these gels might have on pregnancy. The assumption is that they are benign and don't travel up the uterus but pregnant women are usually withdrawn from the trials so in the end there may not be enough data to really know the answer to this.

The bigger issue, though, is that while these virus-halting gels may well avert some 2.5 million new HIV infections a year (and save impoverished nations billions in expensive AIDS therapy), as one 2002 estimate had it, they still, in the end, represent a game of Russian roulette.

Early animal studies with the gels showed they prevented HIV transmission in 50 to 75 per cent of the cases. First-generation microbicides for humans are expected to be about 50 to 60 per cent effective, most researchers assume.

The more advanced ones, that use antiretroviral compounds, may prove to be much more effective. But the concern here is that they could build up resistance in users to antiretroviral (ARV) therapy so that if these women did come down with the virus, the latest life-extending treatments might not work.

The early studies, like an oft-cited one by the London School of Hygiene and Tropical Medicine in 2002, assumed a microbicide that would be 60 per cent effective and used by 20 per cent of the appropriate group.

That may well turn out to be an overly conservative estimate. With WHO estimating there will be close to 45 million new HIV cases between 2002 and 2010 — most of them in the Third World and most of them women — one can only hope so.

Microbicides are very likely a useful arrow in the quiver in the fight against HIV, and a stopgap — maybe even a moral imperative — on the road to a vaccine. But it's highly unlikely they will ever be as effective as a condom in keeping an unwanted virus out of the human body. And they should never be seen as an alternative.