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Topical Microbicides: Removing Barriers to HIV Prevention

April 5, 2001


The Trouble with Condoms

Ask a group of people to word associate the phrase "HIV prevention" and chances are you'll hear a chorus of "condoms!" in return. Thanks to exhaustive safer sex educational campaigns, millions of people know that a properly used condom can successfully impede transmission of HIV and many other sexually transmitted diseases (STDs). Yet millions of people do not use condoms and continue to put themselves at risk. This knowledge/behavior disconnect is reflected in recent increases in infection rates of HIV and other STDs such as syphilis, gonorrhea and chlamydia.

Why, armed with condoms and information, do people continue to put themselves at risk? The reasons are many. Some of them are:

Prevention methods based on condom use, monogamy, and abstinence have failed to keep millions of people from becoming infected with HIV and other STDs. Each day sees as many as 16,000 new HIV infections globally. More than 90% of these HIV infections are transmitted through unprotected sex and at least 5% of those infections are transmitted through anal sex.


Topical Microbicides: New Hope for HIV/STD Prevention

There is no magic bullet solution to stop the spread of HIV and other STDs. Complex issues including poverty, disenfranchisement, and powerlessness defy easy solutions. Meanwhile, people who do not or cannot use condoms need the tools to protect themselves now. As a convenient and practical method of prevention, topical microbicides represent such a tool.


What Is a Microbicide?

A microbicide is any substance that can substantially reduce transmission of STDs, including HIV, when applied in the vagina or rectum. A microbicide could be a gel, cream, film, suppository, sponge, vaginal (or rectal) rings or wipes. Most of the microbicides being developed will probably also have some contraceptive effect -- because it's hard to make something that neutralizes viruses and bacteria but doesn't affect sperm.

Microbicides currently under development work in several different ways:

Two or more of these approaches may be combined with a number of active ingredients to develop a successful microbicide. Right now there are no proven microbicides on the market, although there are at least 60 topical microbicides in development and 23 microbicidal products being tested in people.


How Would a Microbicide Be Used?

Topical microbicides could be used for anal or vaginal sex, along with condoms for extra protection, or instead of condoms when condom use isn't possible. Some have also suggested that a mouthwash-type product would also be useful for protection during oral sex.

Microbicides may also help prevent HIV transmission from mother to baby during delivery by reducing the amount of HIV in an HIV-positive woman's vagina right before she gives birth. This might be especially important in very poor countries where women do not have access to anti-HIV therapy.

Because they are not actual physical barriers, microbicides will never be as good at stopping the transmission of STDs as a condom. However, the success of any method of prevention is a function of not only how effective it is, but how often it is correctly used. Because microbicides may be used more consistently than condoms, they may be more effective in the long run.


How Could Microbicides Benefit HIV-Positive Users?

There are several ways that microbicides could be useful to people who are HIV-positive. Since microbicides neutralize disease-causing organisms in both semen and vaginal secretions, they may give HIV-positive users a way of reducing their partner's risk of contracting HIV during sex. A microbicide could also reduce the risk of two HIV-positive partners being re-infected with different strains of HIV. They may also reduce an HIV-positive person's risk of getting other STDs, bladder infections, or yeast infections. For people with compromised immune systems, this could be an important advantage. It is important to note that condoms can also help with these issues.


What Other Advantages Are There to Using Microbicides?

It is hoped that microbicides will be inexpensive and available over-the-counter like condoms. Successful use of the condom, however, requires the cooperation of insertive sexual partners; successful microbicide use may not even require their knowledge. Microbicides could also offer increased sexual satisfaction while practicing safer sex. In addition to the lack of physical barriers, other characteristics of microbicides such as smell, taste, and viscosity may afford more choices in sexual pleasure.


Microbicide Research

Interest in developing a form of STD prevention that could be used without a partner's knowledge or consent began in the early 1980s. Research and interest in microbicides has almost exclusively focused on vaginal use for two reasons. One is that worldwide, women make up the majority of those exposed to HIV. This is often because they do not have prevention methods that they can control. Furthermore, the number of women infected is the fastest-growing group of new HIV infections, and now represents 45% of HIV/AIDS cases worldwide.

The second reason is that heterosexism has inhibited a broader discussion of anal sex practices and rectal microbicides. Dr. Connie Celum at the University of Washington is responsible for the only research of rectal microbicides on human subjects. She addresses the anal stigma of science, saying "Most of the researchers in this field aren't just homophobic, they are erotophobic." Slowly, more interest and research has focused on finding a product that can be used both vaginally and rectally, although differences in the anatomy and environment may hinder such a formulation, making it necessary to create different products for vaginal versus anal sex. Unfortunately, these considerations are being ignored by many researchers, and funding of rectal microbicides is often being suppressed by conservative activists.

Another barrier to microbicide research is lack of public awareness. People cannot demand what they have yet to imagine. By far the largest barrier, however, is lack of funding. Less than 1% of all federal AIDS funding goes toward finding a successful microbicide.

New drug development is usually funded primarily by major pharmaceutical companies that have the money to invest in large clinical trials. Unfortunately, none of the largest corporations are investing in microbicide research. They are reluctant for a variety of reasons. Their main concern, however, is that microbicides may not be profitable enough to justify the cost of developing them. Those who need the product the most are the least able to afford it. According to Alliance for Microbicide Development, it costs about $20 million to get one product from discovery through Phase II trials of safety. It can then cost up to $20 to $30 million more to get it through the huge Phase III efficacy trials, which can involve as many as 3,000 to 4,000 participants per product. Right now, about $35 million per year, at most, is being spent globally on microbicide research. The U.S. government is providing about $26 million of that. Without additional funding, the money just isn't there to move potential microbicides efficiently through the research pipeline.

The Global Campaign for Microbicides is a broad-based, worldwide coalition of organizations working to engage individuals, community-based organizations and institutions in the advocacy needed to make microbicides a reality soon. Global Campaign has helped Maryland Representative Connie Morella write the Microbicide Development Act. If passed, the Act would increase federal microbicide research funding at the NIH to $50 million in 2001, $75 million in 2002, and $100 million in 2003 -- enough to get the first products through the research pipeline.

More information on microbicide development is available at the website http://www.microbicide.org. You can help get safe, effective microbicides onto our drugstore shelves and into the hands of people who need them all around the world. Everyone who supports this issue may call their representatives and senators and ask them to sign on as a co-sponsor of the Microbicide Development Act as soon as it is re-introduced in Congress. Congressional contact information is available, by state, on the website http://www.congress.org.


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