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Microbicides are products being developed to reduce the spread of HIV and other sexually-transmitted diseases (STDs). Microbicides could come in many forms, including gels, creams, suppositories, films, lubricants, sponges, or vaginal rings. They could be used in the vagina or rectum.
Microbicides could work in different ways:
No. Scientists are testing many products to see whether they help protect against infection with HIV and/or other STDs. Some of these products have proven safe enough in lab studies that they are now being tested in people. However, no safe and effective microbicide is currently available to the public.
Microbicides have been in development for the past 15 years. A number of studies conducted on the early products have failed to find an effective microbicide.
However, there is hope that a new group of microbicides that contain HIV drugs will be more effective. Unlike earlier products, these newer microbicides do not have to be applied at the time of sex. They may be used daily as a gel or possibly as a vaginal ring, that may only need to be inserted once a month.
Promising results were reported in July 2010 from a large study called CAPRISA 004. This study of 889 HIV-negative women in South Africa showed that when women used a one percent gel version of the HIV drug Viread (tenofovir) inside the vagina, two out of every five HIV infections were prevented. These study results provide early proof that HIV drug-based microbicides, in particular tenofovir gel, can help protect women against HIV.
The CAPRISA 004 study also showed that women who used the tenofovir one percent gel had half as many infections caused by herpes simplex virus (HSV-2), or genital herpes. This is important because people infected with HSV-2 are more likely to get infected with HIV as well as to spread it to others.
Unfortunately, a similar study of tenofovir one percent vaginal gel among over 5000 HIV-negative women in Uganda, South Africa, and Zimbabwe was not successful. This study, called the VOICE study (MTN 003), was stopped in the fall of 2011 because it did not work. However, the tenofovir gel appeared to be safe, without major side effects.
The VOICE study was also looking at the effectiveness of taking two different HIV drugs in pill form – Viread (tenofovir) and Truvada (tenofovir/emtricitabine). The tenofovir pill was also stopped because it did not work; however, the part of the study using the Truvada pill is continuing, to see if it works.
There is another study being done now to measure the effectiveness of one percent tenofovir vaginal gel in 1700 HIV-negative women in South Africa. This is called the FACTS 001 study; its results are expected in the spring of 2014. Researchers hope that the FACTS 001 study will help us understand why the CAPRISSA study showed the gel worked and the VOICE study did not.
There is also hope that a vaginal ring containing an HIV drug can prevent the spread of HIV. The ring is flexible and designed to be placed deep inside the vagina against the cervix, where it stays for one month. The benefit of using a vaginal ring compared to a vaginal gel is that women would not have to insert the microbicide ring as often as the gel.
Two studies, the ASPIRE study (MTN 020) and the Ring Study (IPM 027), are looking at a vaginal ring containing an HIV drug called dapivirine (a non-nucleoside reverse transcriptase inhibitor) to prevent the spread of HIV. The ASPIRE study is looking at the ring’s effects in over 3000 women from Malawi, South Africa, Uganda, Zambia, and Zimbabwe. The Ring Study is looking at the effect of the ring in 1650 women from Rwanda and South Africa. Results from both studies are expected in 2015.
Other related ongoing studies include: (1) MTN 008, which is looking at the safety of tenofovir one percent vaginal gel in pregnant and breastfeeding women the US, and (2) safety studies of rectal tenofovir one percent gel.
No. When used consistently and correctly, male or female condoms are likely to provide better protection against HIV and other STDs than microbicides, so they are still the best choice. But for people who do not have access to condoms, or who cannot or will not use condoms, microbicides would provide another option. This is especially true for women whose male partners refuse to use condoms. Microbicides could be used without the knowledge of women’s sexual partners, thereby putting the power of prevention directly in women’s hands. Using microbicides could save lives and have a major impact in reducing the spread of HIV.
Many of the microbicides being tested work against HIV and at least one other STD. In time, a product that combines different microbicides might be developed that could prevent a wide range of STDs, including HIV.
Some of the microbicides being studied would allow a woman to get pregnant. These are called non-contraceptive microbicides. They would offer women the option of getting pregnant while still protecting themselves from infection -- an option that is not available with condom use. The tenofovir one percent gel tested in the CAPRISA 004 study and mentioned above is one example of a non-contraceptive microbicide. Contraceptive microbicides would prevent pregnancy and STDs, including HIV. It is important to have both types available.
Any new product must go through strict safety testing before becoming available to the public. Health activists and researchers are closely watching over the clinical testing of microbicides to make sure that the testing is being done correctly.
It is possible that an HIV-positive woman's male partner might be protected from infection if she used a vaginal or rectal microbicide. However, this would need to be tested in clinical trials. The safety and effectiveness of vaginal microbicides must be tested separately from rectal microbicides.
Microbicides could help protect HIV-positive women from re-infection with other HIV strains and from other STDs.
Research on developing a vaccine to prevent HIV infection has not been successful so far. Microbicides may be available sooner than a vaccine to prevent HIV. Even if a safe and effective vaccine is discovered, vaccines and microbicides will both have roles to play in the prevention of HIV.
Advocates are working with researchers and policy makers to make sure that any approved microbicide will be as affordable and accessible as possible.
N-9 products are sold over the counter as spermicides that can prevent pregnancy. They cannot prevent the transmission of HIV or other infections. In fact, when used more than once a day, N-9 contraceptive products may actually increase HIV risk by irritating the skin of the vagina. Other studies show that N-9 is even more irritating to the rectum than to the vagina.
According to the World Health Organization (WHO):
Until microbicides are available, the best way to protect yourself and your partner from STDs, including HIV, is by using a male or female condom. It is also important to avoid the use of nonoxynol-9 (N-9) products if you think there is any chance you may be exposed to HIV. Getting tested for STDs regularly and getting treatment quickly if you have an STD will also help reduce your risk of HIV infection if you are exposed to HIV.