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HIV Prevention
Overview of HIV Prevention

Released: September 17, 2020

Expiration: September 16, 2021

Joseph J. Eron
Joseph J. Eron, Jr., MD
Sharon L. Hillier
Sharon L. Hillier, PhD
Daniel R. Kuritzkes
Daniel R. Kuritzkes, 医学博士
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Contraception

There are 2 types of barrier devices used by women for prevention of pregnancy and as prophylactic barriers to reduce the risk of HIV and sexually transmitted infections: diaphragms (or cervical caps) and female condoms. These devices can allow women more control over sexual health because their use does not require active participation by the male partner and can be used if the male partner refuses to use male condoms.33

Diaphragms
Unlike male condoms, diaphragms and other cervical caps can be inserted hours before sexual activity and do not necessarily disrupt the sequence of sexual activities leading up to intercourse. In addition, these devices are relatively inexpensive and reusable. The biological rationale for the use of diaphragms for prevention of HIV is that the endocervix is an anatomical site having a dense concentration of receptors for HIV infection, as well as being the preferential site for infection by many other sexually transmitted infections, which increase HIV risk. One obvious limitation of cervical barrier devices is that they cover only the cervix; the vagina and urethra are still exposed to infectious pathogens. However, the cervix is covered by a thin columnar epithelium and is therefore more fragile and susceptible to disruption than the vagina, which is lined by squamous epithelial cells.

One study evaluated the impact of diaphragm use on the incidence of HIV infection. The MIRA study recruited nearly 5000 women from 1 site in Zimbabwe and 2 sites in South Africa. All women received male condoms, intensive risk reduction counseling, and treatment for any current STDs. The MIRA trial found that women randomized to diaphragm use along with an over-the-counter lubricant gel (polycarbophil) were no less likely to acquire HIV than women who did not use a diaphragm (Table 1).34

Table 1. Number of HIV Infections Among Women Enrolled on the MIRA Study

 

At the completion of the study, differences were seen in male condom use between the 2 groups. Male condoms were used in 85% of the most recent sex acts by women in the control group whereas condoms were used in only 54% of the most recent sex acts among women who received diaphragms. Compared with the control group, women and their male partners assigned to the diaphragm group were 33% more likely to have used some barrier method during sexual activity (either a condom or diaphragm),35 which should have led to a deceased incidence of HIV infection. However, product substitution (ie, deciding to use a diaphragm instead of a condom in the previous 3 months) was reported by 83% of women at one or more visits in this study, suggesting that women in the study frequently substituted the diaphragm for male condoms. Because there was a difference in the rate of male condom use between the groups in this study, it is difficult to assess the independent impact of diaphragm use on STD incidence. As a result, this study was broadly interpreted to mean that there is no public health value in promoting diaphragms in addition to male condoms for the prevention of HIV infection in women.

Female Condoms
Female condoms have been available for the past decade, and a new lower-cost version of the female condom was approved by the FDA in 2009. If women are able to use female condoms when male condom usage cannot be negotiated, then the number of sexual acts protected by a barrier method should increase when female condoms are provided. In one study conducted in the United States, acts of protected sex increased from 44% to 59% after female condoms were provided.36 There has been very limited research to date to demonstrate that the female condom is effective for prevention of sexually transmitted infections. Because female condoms are more expensive than male condoms, broad provision of female condoms has not been successful, although some countries are beginning to evaluate more targeted programs to provide female condoms to women at increased risk of infection.

Female condoms have been advocated for use by both MSM and women having anal intercourse, although the data supporting the safety and acceptability of female condoms for receptive anal intercourse are lacking.37 Those wishing to use a female condom during anal sex should be advised to remove the flexible inner ring, which is intended only for vaginal insertion.

Hormonal Contraceptives and Risk of HIV Acquisition in Women
There has been considerable controversy in recent years surrounding the potential for increased risk of HIV infection associated with use of hormonal contraceptives in women. This debate has been fueled primarily by conflicting observational data on HIV infection risk among women receiving injectable hormonal contraceptives.38-40 Whether injectable hormonal contraceptive use is associated with HIV acquisition remains controversial and additional well-designed studies are needed to provide clarity.41,42

One study suggests that injectable contraceptives may confer differential susceptibility to acquisition of HIV infection.43 Among 3141 women using contraception in an HIV prevention study in South Africa, women using depot medroxyprogesterone acetate had a 50% higher risk of incident HIV infection compared with users of norethindrone enanthate, another type of injectable contraceptive (adjusted HR: 1.41; 95% CI: 1.06-1.89 P = .02).

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