Scientists Search for HIV Prevention Methods Women Can Control
The message has been delivered millions of times, on thousands of posters and brochures, across the air waves and in classrooms and dusty village squares all over the world: Use a condom every time you have sex to avoid becoming infected with HIV. This barrier method remains the single most effective and affordable technology available to protect people from HIV/AIDS and other sexually transmitted diseases (STDs).
Yet for half the world's population, this message is a painfully mixed one. Women who are economically dependent on and socially subordinate to men often lack the power to negotiate condom use with their partners. Male resistance to condom use can be a formidable barrier to women's protection.
The need for prevention options that women can control is becoming more urgent as the epidemic continues to spread rapidly among women. Many experts believe that worldwide, more women than men will be HIV-positive by the end of the century. In some regions, such as sub-Saharan Africa, more women than men are already infected. As with several other STDs, women are more biologically susceptible to HIV infection than men--transmission from an infected man to a woman is easier than from an infected woman to a man.
Giving women new ways to protect themselves from other STDs is important, since STD infections make it easier for HIV to pass from person to person. Also, the medical consequences of having an STD infection can be more serious for women, leading to pelvic inflammatory disease or infertility. STDs among women are more often asymptomatic than infections among men and are more difficult to diagnose, which could delay timely treatment.
Today the only female-controlled STD prevention strategy is the use of existing barrier contraceptives. The recently developed female condom is not widely available outside Europe and North America, and it is relatively expensive. Spermicides and other barrier methods that can be used without a man's knowledge offer a limited degree of protection. Research is under way to develop a new category of prophylactics called microbicides that would offer better protection against many STDs, including HIV.
Female Condoms
The female condom is one prevention method controlled by the woman who uses it, although some cooperation from a male partner is still necessary. Female condoms are made of a polyurethane plastic that is sturdier than the latex used in male condoms, potentially offering greater protection, less frequent breakage, improved comfort and longer shelf life, even under unfavorable storage conditions.
The device covers the cervix, the vagina, and a portion of the female perineum, as well as the base of the penis. Since it covers much of the external female genitalia, it provides a more extensive barrier and may offer somewhat greater protection than male condoms against genital ulcer diseases, such as herpes and chancroid.
Laboratory studies have found that the female condom is impermeable to various STD organisms, including HIV. The one study involving human use was a clinical trial conducted by Family Health International (FHI) and the Contraceptive Research and Development Program (CONRAD).
In the trial, 104 women who had previously been diagnosed and treated for recurrent vaginal trichomoniasis were assigned to a group using the female condom or to a control group (volunteers who indicated they would not use the condom). After 45 days, reinfection with trichomonas occurred in seven of the 50 controls (14 percent) and five of the 34 non-perfect users (14.7 percent), but in none of the 20 participants who reported perfect use of the female condom.1
FHI and the World Health Organization (WHO) will conduct at least one study of female condom use and cervical infection. Until more research is completed, the female condom's ability to prevent STD infection remains speculative, but promising, says Dr. Paul Feldblum of FHI, who specializes in barrier methods.
Acceptability
Women in industrialized countries are beginning to use the female condom for protection against STDs. The United States Agency for International Development (USAID) recently provided a limited supply of female condoms to family planning and health programs in 22 developing countries. USAID will carefully evaluate whether to continue supplying them.
But widespread use will depend on users' attitudes. Dr. Feldblum noted that the device was new and unfamiliar to most people. "The female condom may become more appealing with time, as people become more accustomed to the concept," he said.
For six years, FHI has evaluated the acceptability of the female condom among diverse populations. In the clinical trial by FHI and CONRAD, the most frequent complaints were not liking the inner ring and movement of the device during use. There were few insertion-related complaints, although some women said that it took more than one attempt to get used to inserting the condom. Many women reported that they liked using the device and would recommend it to others.
In another study, 56 Thai couples reported that they found the device to be generally acceptable, but that the outer and inner rings caused an uncomfortable feeling during intercourse. Most of the couples reported decreased sexual satisfaction. Many of the men felt the device was too large. A group of 20 Thai prostitutes reported that the female condom was too long.2 A second study was conducted with these women using a shorter device, but the overall acceptability improved only marginally.
A study sponsored by the AIDS Control and Prevention (AIDSCAP) Project's Women's Initiative in Kenya and Brazil is investigating women's perceptions of the female condom as a protective method against HIV and other STDs. This research, which began in October 1995, will examine the influence of various social, cultural and economic factors on acceptability and the degree to which women feel use of a female-controlled method increases their power within a relationship.
Cost is another barrier to more widespread use of the female condom. The average price is $2.50 each in the United States--about five times the price of a male condom. Studies are under way to determine whether female condoms can be cleaned and used more than once. If multiple use is feasible, using the device would be less expensive.
Spermicides
Spermicides are sometimes recommended as a fall-back method when condom use is unacceptable and risky sexual contact is inevitable, since spermicides appear to offer some protection, especially against bacterial STDs.3 In the United States, for example, the New York State Department of Health recommends the use of a diaphragm and spermicide when abstinence or condom use is not feasible. As a last resort, it suggests that women use a spermicide alone, although this method offers the least protection from infection.
In laboratory studies, the widely used spermicide nonoxynol-9 (N-9) inactivates many STD pathogens, including HIV. Gonococci, chlamydia, genital herpes, spirochetes, candida, trichomonas and organisms causing vaginosis are inactivated by N-9. Since spermicides are designed to kill sperm cells, they should also destroy HIV infected cells found in the semen of HIV-positive men. How well spermicides work, however, depends on proper dispersal in the vagina and other factors. Also, N-9 is occasionally irritating to vaginal and cervical cells, especially with frequent use, which can increase the risk of HIV infection.
Not enough research has been done to evaluate how effective N-9 use can be in protecting a woman from viral infections like HIV. "How much N-9 coverage is needed is among many important questions that need to be answered," Dr. Feldblum cautioned. "For example, keeping N-9 use below the threshold of causing irritation may actually lower the risk of contracting HIV, while frequent use and tissue irritation may enhance HIV transmission."
With funding from the U.S. National Institutes of Health, FHI is studying whether N-9 vaginal film use reduces HIV infection among women with multiple partners. WHO recently completed safety trials of the film among healthy volunteers in Amsterdam, Antwerp and Bangkok and is planning further studies in two African countries and one Asian country. Benzalkonium chloride and menfegol, spermicides that are widely used in some countries, also have inactivated HIV in laboratory tests, but more research is needed to evaluate their ability to protect against viral infections.
Searching for Options
Scientists are developing vaginal products that may eventually improve upon some of the shortcomings of currently available spermicides. Ideally these chemical barriers would protect a woman against a wide range of infectious agents and viruses, including HIV. Like spermicides, they could be applied vaginally in a gel, film or insert.
Investigators in India are testing the safety and effectiveness of a vaginal cream made from the neem tree that has contraceptive and microbicidal properties. The Population Council is conducting clinical trials to assess the safety of another microbicidal compound. The U.S. National Institute of Allergy and Infectious Diseases (NIAID) recently began three research projects to find topical microbicides that can control the spread of HIV and other STDs. And CONRAD is screening many compounds for antiviral activity and local tissue safety.
USAID provides much of the funding for microbicide research conducted by CONRAD, NIAID, WHO, the Population Council, FHI and the U.S Centers for Disease Control and Prevention. These organizations and the Medical Research Council in the United Kingdom are part of an interagency working group organized by WHO to coordinate their activities and advocate for greater support for microbicide development. The group has developed models for preclinical research on microbicidal compounds and guidelines for clinical trials.
An ideal microbicide would not necessarily kill sperm, making the product attractive to women who want to become pregnant. It could be combined with a spermicide for women who do need contraception.
Many problems need to be resolved, suggesting that it will be years before a microbicide is available for general use. For example, the mechanism for how HIV is transmitted within the female reproductive tract is not clearly understood. Knowing more about the precise ways HIV transmission occurs will help scientists develop such a prophylactic microbicide.
-- Nash Herndon
Nash Herndon is managing editor of FHI's quarterly bulletin, Network.
References
Soper, D.E., D. Shoupe, G.A. Dhangold, et al. 1993. Prevention of vaginal trichomoniasis by compliant use of the female condom. Sexually Transmitted Diseases 20:136-139.
Sakondhavat, C. 1989. Consumer preference study of the female condom in a sexually active population at risk of contracting AIDS: Final report. Durham: Family Health International.
Cates, W., F. Stewart, J. Trussell. 1992. The quest for women's prophylactic methods--Hope vs. science. American Journal of Public Health 82:1479-82.
