Microbicide FAQ
1. What is a microbicide?
2. Will different HIV microbicides be necessary for vaginal and rectal use?
3. Will a microbicide cure AIDS?
4. If an effective microbicide is found, will we still need to use condoms?
5. How would an HIV microbicide work?
6. What are the characteristics of an effective HIV microbicide?
7. How can I get involved in the search for an HIV microbicide?
What is a microbicide?
A microbicide is a an agent that destroys microbes. Topical microbicides, applied to mucosal surfaces, act as chemical barriers to prevent the spread of Sexually Transmitted Diseases. Several microbicide candidates are under investigation to determine if they reduce the transmission of HIV when inserted into the vagina or rectum. A microbicide can be produced in many forms including gels, creams, suppositories, films or in combination with a sexual lubricant. A microbicide offers potential as a prevention option that both women and men could easily control, with or without the consent, or even knowledge, of their sexual partner.
Will different HIV microbicides be necessary for vaginal and rectal use?
Most likely, different microbicides will be needed for the vagina and for the rectum because of differences in their physical structure and properties. An effective rectal microbicide must take into account that HIV is more easily transmitted during anal rather than vaginal sex.
Will a microbicide cure AIDS?
Microbicides would not be a cure, but rather an HIV prevention option.
If an effective microbicide is found, will we still need to use condoms?
Condoms, especially when used in conjuction with a microbicide, will still be the safest option. But for people who can’t or won’t use condoms (sex workers, women who are unable to require their sex partners to use a condom), an HIV microbicide could provide a critical option that they could control without the consent, or even the knowledge, of their sexual partners.
How would an HIV microbicide work?
An HIV microbicide could work in 5 different ways:
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Killing or de-activating pathogens. A microbicide could inhibit HIV infection by breaking down the surface of the virus or pathogen.
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Create physical barriers. Gels or creams could provide a physical barrier between pathogens or viruses and vulnerable cells in the epithelium (cell wall) of the vagina or rectum.
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Strengthening the body’s normal defenses. The body has several naturally occurring defense mechanisms that a microbicide might be able to supplement or enhance. For example, lactobacillus is a naturally occurring, “good” bacteria that helps protect the vagina by maintaining its acidic environment. This natural acidity helps foster an inhospitable environment for many pathogens, including HIV. A microbicide that supports the lactobacilli in performing this function might inhibit infection by HIV or STDs.
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Inhibiting viral entry. A microbicide could inhibit viral or bacterial infection by interfering with the binding of viral proteins to cellular receptors. For example, infection with the HIV virus occurs through binding of gp120 (on the outside of the virus) to receptors on a cell's membrane. A potential microbicide might interrupt this process by binding to receptors in advance, thus blocking the sites and preventing HIV attachment to the cell.
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Inhibiting viral replication. Formulated as gels or creams, anti-HIV medications that are already FDA approved and available might be able to suppress replication of HIV in the vagina or rectum during sexual intercourse.
What are the characteristics of an effective HIV microbicide?
An effective HIV microbicide would:
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Be active against a range of STDs, as well as HIV. Ideally, a microbicide would work against all STDs (syphilis, warts, herpes, chlamydia, gonorrhea, HPV, Hepatitis B) but this would be difficult to achieve since STDs can be either bacterial or viral.
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Not irritate the rectal and vaginal tissue (Nonoxydol-9, a spermicide which is still available in some personal lubricants, was found to irritate the rectal lining, increasing the possibility of HIV transmission.)
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Be available with and without spermicidal agents that prevent pregnancy
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Stay effective over a long period of time.
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Be acceptable and easy to use.
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Remain stable at high temperatures.
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Not be absorbed into the rest of the body, meaning that it would remain in the rectal or vaginal cavity.
How can I get involved in the search for an HIV microbicide?
If you are interested in volunteering for a microbicide study, please contact AIDS Research Alliance at 310/358-2429, or email us at microbicides@aidsresearch.org
