In a study involving over 3,000 women in the US and Africa, an international team of scientists has found the microbicide gel, known as PRO 2000, to be safe and nearly 30 per cent effective in preventing male-to-female sexual HIV infection. This is the "first human clinical trial" in women to show encouraging signs of success, the scientists have claimed. 
Why should I be aware of this?
The best weapon against AIDS will ultimately be a vaccine, and intense research is going on around the world to find one. But it could be years before even a partially effective vaccine is developed. Meanwhile scientists in several countries have been investigating a relatively low-tech approach to AIDS prevention - vaginal medications, called microbicides, that stop the transmission of HIV during sex. But it might be the developing world's best short-term hope for curtailing this deadly pandemic.
The study, funded by the National Institute of Allergy and Infectious Diseases (NIAID), while not conclusive, provides a glimmer of hope to millions of women at risk for HIV, especially young women in Africa.
All about anti-HIV gel
Microbicides were hailed as an important new weapon in HIV prevention. A female-controlled method is especially needed in poor countries where women often can't persuade men to use condoms.
The potential of microbicides was first recognized in the early 1990s by a number of government research agencies, private organizations and multinational bodies like the World Health Organization. In 1994 the International Working Group on Microbicides was set up, whose members now include experts from 21 government and non-governmental organizations from rich and poor nations.
The current study
The study investigators found the microbicide gel - known as PRO 2000 - to be safe and approximately 30 percent effective (33 percent effectiveness would have been considered statistically significant). This is the first human clinical study to suggest that a microbicide - a gel, foam or cream intended to prevent the sexual transmission of HIV and other sexually transmitted infections when applied topically inside the vagina or rectum- may prevent male-to-female sexual transmission of HIV infection.
Earlier focus on "safer sex"
Efforts to bring the AIDS pandemic under control have focused on the "safer sex" approach. It concentrated on urging people to use condoms and limit their sexual partners. The fact that condoms, if used correctly and consistently, offer good protection against HIV and other infections is shown by results in Thailand, Uganda and a few other developing countries.
But in most nations where HIV is a major threat the safer-sex message is not being heeded sufficiently as many people dislike interrupting sex to put on a condom, and the resulting reduced sensitivity.
Another major drawback about condoms is that their use requires the man's agreement. In societies where women have little power they can find it impossible to get their partners to wear one.
Option with women
With microbicides, women would have the option of taking action themselves, if necessary, without their partners' agreement or even knowledge. Being colorless, odorless and tasteless, they would be undetectable and not pose a physical barrier that reduced pleasure. Some products might even have positive attributes such as lubrication and perfume to act as "sex enhancers.”
Many of the anti-HIV microbicides being investigated also destroy the organisms which cause other sexually transmitted diseases such as gonorrhoea, chlamydia and genital herpes. And when possible they could be used along with condoms.
Significantly, the first products could reach the market within five or six years. Around fifteen other chemicals are in early-stage human trials and some forty others are in preclinical studies. Many work in the test tube against a wide range of HIV strains from different continents.
- Some 5 million people became infected with HIV last year, most of them living in Sub-Saharan Africa.
- Currently, women comprise half of HIV-affected people worldwide. 
- In several southern African countries young women are at least three times more likely to be HIV-positive than young men. 
- In most cases, women become infected with HIV through sexual intercourse with an infected male partner. 
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