Microbicides: New Barriers Against HIV
Ithough you probably have never heard about microbicides, they are one of the most promising new developments in the fight against STIs (Trager, 2003). Microbicides are chemical substances that can significantly reduce STI transmission when applied vaginally or rectally. They come in many forms, such as creams, gels, suppositories, lubricants, and dissolving film (Gottemoeller,
2001) . Microbicides work by killing microbes, or pathogens that are present in semen or vaginal fluids. These products can be used by couples trying to avoid a pregnancy and an STI, and also by couples who are infected with STIs but are trying to become pregnant.
Some traditional spermicides have antimicrobial properties, including nonoxynol-9 (N-9; see Chapter 13 for more information). Although N-9 has been at the forefront of the fight against STIs, we now know that frequent use of N-9 spermicide has been found to cause irritation of the cervix and vagina, which may actually help in the transmission of HIV (Gayle, 2000). In fact, HIV transmission has been found to be higher in a population using N-9 than in a population using a placebo (Van Damme et al., 2002). Other studies showed that 15 minutes after N-9 was applied rectally, severe peeling and scaling of the inside layer of the rectal epithelium occurred, leaving the skin more exposed to STI infection (Maguire, 2002). Because of this, N-9 is no longer recommended as a microbicide.
Condoms have always been our number one defense against STIs; however, their use must be negotiated with a partner, and because of this they aren’t used as often as they should be (remember that in Chapter 13 we learned that almost 20% of young women believe that they don’t have the right to tell their partner they won’t have intercourse without using condoms; Rickert et al., 2002). Microbicides can be used by one partner without negotiation, and studies have shown that microbicides are more accepted than condoms. In fact, 90% of men in one study said they would not object to their partners using these products (Callahan, 2002). Microbicides could help to reduce the number of HIV infections by 2.5 million over 3 years (DePineres, 2002).
As of early 2006, microbicides were not yet available to the public. Much of the research is being done by smaller companies because of reduced funding. A phase-three trial (we discussed how FDA approval works in Chapter 13) must enroll thousands of participants and can cost up to $46 million (Alliance for Microbicide Development, 2001). Larger pharmaceutical companies have stayed away from the development of microbicides mainly because they will be low cost and over the counter, which doesn’t give the companies much incentive to develop them (Gottemoeller,
Many schools are beginning to include HIV education in their classes. These programs provide students with information about risky sexual behaviors, facts about AIDS, and prevention strategies. Different educational programs emphasize different messages. One may discourage sexual activity, whereas a second provides information about condom use, and a third stresses monogamy. All are similar in that the goal is to change behavior and increase self-responsibility. However, these programs have not progressed without controversy. People disagree about when these programs should start, how explicit they should be, and whether or not such education will increase sexual promiscuity.
Once a diagnosis of HIV has been made, it is important to inform all past sexual contacts to prevent the spread of the disease. Because the virus can remain in the body for several years before the onset of symptoms, some people may not know that they have the virus and are capable of infecting others.
It seems reasonable that before we can determine what will reduce high-risk behaviors that contribute to increases in HIV and AIDS, we need to know the behaviors in which people are engaging. Yet data on sexual practices are lacking in the United States. As you remember from Chapter 2, many of our assumptions about current sexual behaviors are based on the Kinsey studies from the 1940s and 1950s. We know very little about current rates of high-risk behaviors, such as anal intercourse, extramarital or teenage sexuality, and homosexuality. The National Health and Social Life Survey helped shed some light on these behaviors, and two ongoing surveys, the Behavioral Risk Factor Surveillance Survey (BRFSS) and the Youth Risk Behavior Surveillance Survey (YRBS), continue to collect and monitor information about risk behaviors at the state level (see Chapters 2 and 8 for more information about these studies).
In 2003, after years of hard work, the first AIDS vaccine (AIDSVAX) was found to be ineffective in FDA clinical trials (see Chapter 13 for more information about the FDA approval process; also see Sex in Real Life, “Vaccines for Sexually Transmitted Infections?” on page 507). In 2005, the National Institute of Allergy and Infectious Diseases granted more than $300 million to establish a new center for HIV/AIDS vaccine development (Markel, 2005). Ongoing national and international trials are taking place for the development of an HIV vaccine. As of 2005, there were two ongoing trials for a therapeutic HIV vaccine that helps delay the progression of the disease rather than preventing the onset of the disease. Unfortunately the development of an HIV vaccine could take years. The polio vaccine took 47 years to produce, and it is anticipated that the HIV vaccine may take just as long (Markel, 2005). Researchers will continue to work on the development of an AIDS vaccine.