Lecture | Quiz | Learning Exercise | Answer Key

Developed by JHPIEGO’s Training in Reproductive Health Project with funding from USAID.

Lesson 3: Prevention of Sexual Transmission of HIV
Instructor: Jean Anderson, MD

Objectives

In this lesson, we shall be reviewing how to prevent sexual transmission of HIV. By the end of this lesson, participants will be able to:

• Describe progress made in HIV prevention
• Discuss the factors involved in sexual transmission of HIV
• Talk to clients about effective interventions for prevention of sexual transmission

Introduction

Even though HIV is increasingly a treatable disease, there is no cure on the horizon. And, in low-resource settings, which bear the greatest burden of disease, treatment resources remain limited or nonexistent. This makes prevention of HIV infection even more important. We have known ways to prevent transmission and acquisition of HIV for many years. However, many sexually active adults and adolescents living in the developing world do not believe they are at risk of getting AIDS.

When we examine the actual HIV prevalence rate among pregnant women in major cities in developing countries, there is a significant difference between perception and reality. For example, although half of young sexually active women in Zimbabwe feel they are at no risk for contracting AIDS, one third of pregnant women in major urban areas in Zimbabwe are already HIV-infected and will develop AIDS (1). Even in countries where the HIV prevalence is much lower, many young women do not think they are at risk of getting AIDS. As a result, they will be less likely to protect themselves with safer sexual practices.

The reasons people may think they are not at risk for HIV/AIDS include lack of knowledge about HIV infection, how it is transmitted and the level of risk in their area. However, it may also be because they do not know or believe that their behavior or their partner’s behavior places them at personal risk for becoming infected with HIV. This underscores the importance of wide-reaching education to convey accurate information about HIV, to counter or dispel misperceptions and myths and, most important, to promote prevention. 

Prevention Can Work!

In Uganda, the HIV epidemic was recognized relatively early and prevention efforts were started on a national level, including:

• commitment and involvement of political, community and religious leaders,
• radio messages on HIV/AIDS,
• social marketing of condoms, and 
• extensive availability of HIV voluntary counseling and testing. 

Since 1989 these efforts have resulted in a delay in the age of first sexual experience of both young men and women.(2) 

Few countries have shown the link between behavior and HIV infection as clearly as Thailand. Overall, behavioral changes have reduced the number of new HIV infections each year from almost 143,000 in 1991 to 29,000 in the year 2000. With support from the Thai government and leaders from all levels of society, emphasis was placed on reducing the risky sexual practices and the vulnerability of young people as well as on more specific risky behaviors of particular groups. Efforts were made to increase knowledge and awareness of HIV, as well as to improve life skills, such as decision-making and negotiation. Condoms were promoted and educational opportunities for young girls were increased so that they were less likely to become prostitutes. Also, national policy guidelines to protect the human rights of people living with HIV/AIDS were issued. One of the most striking effects of the national program was a reduction in visits to prostitutes, the behavior most closely linked with HIV infection in Thai studies. (3) 

Modes of HIV Transmission

There are three major ways HIV can be transmitted. First of all, HIV is transmitted through parenteral exposure, where there is a break in skin integrity and direct exposure to infected blood or blood products. HIV is very efficiently transmitted with transfusion of infected blood. In fact, there is a 95% chance of infection when a single unit of HIV-infected whole blood is transfused. Contaminated transfusions remain a significant problem in areas where the blood supply is not routinely screened for HIV. Injection drug use carries a risk of 0.67% per exposure and is responsible for the recent dramatic increases in HIV infections in Eastern Europe. Healthcare workers have an approximately 0.4% risk of contracting HIV per needlestick exposure from an infected patient. (4)

The second major mode of HIV transmission is mother-to-child transmission during pregnancy, labor and childbirth, or with breastfeeding. Without access to therapies known to decrease risk, perinatal transmission occurs in 25–45% of pregnancies where the mother is HIV-infected. 

The third major mode is sexual transmission, primarily heterosexual. Globally, it is the most common mode of HIV transmission. This is the topic we will spend the rest of this lesson discussing. 

There is no evidence that HIV is transmitted by insect bites, kissing or hugging an infected person, touching toilet seats or by sharing eating utensils.

Factors Involved in Heterosexual Transmission

The magnitude of risk varies with different types of sexual activity. The greatest risk per episode is with receptive vaginal or anal intercourse, which means that women are at greater risk for sexual transmission of HIV. Anal sex is somewhat riskier than vaginal sex. Although the risk with oral sex is low, there are now data to suggest that it may account for a significant minority of transmissions, particularly in sex between men.

There are several factors that may increase or decrease the risk of sexual transmission of HIV(5):

1. Disease progression: Individuals newly infected with HIV infection and those with more advanced disease or AIDS are more infectious because they have higher levels of virus in their blood and genital secretions.
2. Antiretroviral (ARV) therapy: ARV therapy lowers the amount of virus in an infected individual and therefore reduces the risk of transmission. 
3. Sexually transmitted infections (STIs): Increase both infectiousness and susceptibility to HIV approximately 2–5 times.
4. Circumcision: Uncircumcised men appear to be at increased risk of transmitting and acquiring HIV.
5. Menses: May increase risk of HIV transmission
6. Pregnancy: May increase risk of HIV transmission
7. Cervical ectopy: May increase risk of HIV transmission.
8. Barrier contraceptive methods (including the male and female condom): These provide the greatest protection against both transmission and acquisition of HIV. 
9. Hormonal contraception: The role in HIV transmission is inconclusive, although some data suggest that they may increase genital tract HIV shedding. 
10. Spermicides (most of which include nonoxynol-9 as the spermicidal agent): Although spermicides show activity against HIV in the laboratory (and against gonorrhea and chlamydia), a recent clinical trial in Africa and Thailand found significantly increased rates of HIV seroconversion in nonoxynol-9 users as compared to placebo. This trial was conducted in prostitutes who averaged over 3 partners daily. It is not clear what the risk of using spermicides is in women who have fewer partners in lower risk situations.
11. Intrauterine device (IUD): Associated with increased susceptibility to HIV transmission in an Italian cross-sectional study, but not in prospective studies.

Prevention of Sexual Transmission of HIV (6)

There are a number of interventions that can reduce HIV infection rates from heterosexual activity or reduce the incidence of behaviors known to increase risk of HIV transmission. These include: 

1. Voluntary counseling and testing (VCT)
2. Behavioral interventions to reduce risk behavior
3. Use of male or female condoms
4. Dual protection
5. Prevention and treatment of sexually transmitted infections (STIs)

Voluntary Counseling and Testing

In the last lesson, we discussed the studies that demonstrated that HIV counseling and testing are effective in reducing HIV risk behaviors and also can reduce actual rates of HIV or other STIs. Several well-designed randomized and controlled trials have evaluated the effectiveness of different behavioral intervention strategies. Most conclude that such interventions result in decreased sexual risk taking and, in some studies, STI and HIV incidence. Behavioral interventions to prevent HIV infection include knowing basic information about HIV including:

• What is HIV and what is AIDS
• The natural history of HIV infection
• How HIV is transmitted; and 
• How transmission can be prevented. 

However, knowledge is not enough to motivate change. Individuals must also be helped to recognize their personal risks and be motivated to change. Healthcare providers should help individuals identify barriers to risk reduction and develop strategies to overcome them. The individual and the healthcare provider can then formulate a personalized risk reduction plan. Behavioral interventions do not necessarily include HIV testing. 

Behavioral Interventions

Delaying the start of sexual activity, lowering the number of lifetime sexual partners, practicing monogamy and abstaining from sexual activity all will help reduce the risk of both HIV infection and other STIs. Non-penetrative sex or mutual masturbation can be safer and satisfying alternatives to intercourse. Certain practices, such as anal sex, dry sex in which herbs or other substances are used to dry the vaginal mucosa, and douching may increase trauma and irritation to mucosal surfaces. This may possibly increase infectiousness and susceptibility. Sex should be avoided during menses because this may increase both infectiousness and susceptibility. Use of alcohol or drugs increases the likelihood of unsafe sexual practices, because people are less inhibited. But perhaps the best way to reduce the risk of sexual transmission is by using a condom with every act of sex. 

Condoms

Promoting the use of condoms is the most basic and the most important HIV prevention activity. In Uganda, the national HIV program resulted in significant increases in the percentage of sexually active men and women of all ages who had ever used a condom.(2) 

When they are used consistently and correctly, male and female condoms are the most effective methods in preventing HIV transmission and transmission of most STIs, as well as acquisition of these infections. Note, natural skin condoms are not recommended. Because of the porous nature of these condoms, they do not protect the users from HIV transmission.

Male Condoms

Clients should be instructed in the proper use of condoms. Only water-based lubricants or appropriate spermicide should be used with latex male condoms. Oil-based lubricants, such as petroleum jelly, cooking oils, shortening, or lotions result in a 90% reduction in latex strength in just 60 seconds and promote breakage. For latex condoms to be effective they should be stored in a cool, dry area, out of direct sunlight to prevent deterioration. Common errors in use of male condoms include delaying condom application until just prior to full penetration, failure to extend the male condom all the way to the base of the penis, insufficient application of a water-based lubricant, and failure to hold the base of the condom during withdrawal. Finally, it is essential to emphasize consistent condom use with every sexual act. This means that for condoms to be effective for prevention of HIV and STI transmission, they must be used even when prevention of pregnancy is not needed; in postmenopausal women, during pregnancy, when the woman or her partner is infertile, or when other more effective contraceptive methods are used. 

Female Condoms

Even though the female condom is more expensive than the male condom, there is evidence that it may be cost-effective and even cost-saving in reproductive health programs, particularly in groups that practice high-risk behaviors. Furthermore, the female condom has some benefits over the male condom. First, it is made of polyurethane, while most male condoms are made of latex. Polyurethane is stronger than latex and causes no allergic reactions. Unlike latex, polyurethane may be used with both oil-based and water-based lubricants and is not susceptible to deterioration from temperature or humidity. It is not tight or constricting. It can be inserted prior to intercourse and does not require immediate withdrawal after ejaculation, so it will not interrupt sexual spontaneity. The female condom offers more extensive barrier protection, covering both the woman’s internal and external genitalia and the base of the penis. Furthermore, unlike the male condom, female condoms can be reused if washed, rinsed and air-dried after use. The female condom has no serious side effects. Less than 10% of users report only mild temporary irritation. 

Dual Protection

Dual protection is defined as protection against pregnancy as well as HIV and other sexually transmitted infections. Dual protection can be achieved in the following ways:

• By avoiding penetrative sex
• By practicing mutual monogamy between noninfected partners using an effective method of contraception
• By using condoms alone
• Or by using condoms and another method of contraception 

If condoms are used correctly and consistently with every act of sex, they are very effective, providing 98% protection against HIV and STIs and 95–97% protection against pregnancy. Although other methods of contraception may provide the same level or better protection against pregnancy, they provide little, if any protection against HIV and STIs. 

Prevention and Treatment of STIs

Prevention and treatment of STIs is another important component of HIV prevention. There are a number of ways that STIs and HIV are closely linked. 

First, both ulcerative and nonulcerative STIs increase the risk of HIV transmission 2-5 times and genital ulcers disrupt the epithelial barrier. STIs also increase the number of cells vulnerable to HIV in the genital tract, increasing susceptibility in uninfected individuals. On the other hand, HIV-infected persons with STIs have increased genital tract HIV viral load, which increases infectiousness. Indeed, in one clinical trial in Tanzania, syndromic treatment of STIs decreased HIV seroconversion by 38% over 2 years. 

The best way to prevent STIs is to reduce sexual risk behaviors and to use condoms consistently and correctly. Both men and women should be educated about personal risk factors and early symptoms of STIs. They should be encouraged to seek care and treatment as early as possible, if symptoms occur. In areas where laboratory facilities are not available, treatment of STIs is based on groups of symptoms and signs that may be explained by more than one condition. Treatment is given for all of the most likely STIs causing the syndrome, based on local epidemiologic data. The syndromic approach is quite effective for management of genital ulcers and urethral discharge, but is less useful in managing women with abnormal vaginal discharge because of decreased accuracy in the diagnosis and treatment of cervicitis. 

Reproductive health programs for women should have linkages with STI programs treating symptomatic men, so that asymptomatic infections, which are more common in women, may be identified or presumptively treated. All sexually active individuals are at risk for STIs and need education and risk reduction counseling. However, individuals who have high rates of partner change and high rates of STIs have a major impact on maintaining both STI and HIV epidemics. Targeting these “core transmitters,” including prostitutes and their clients, drug users, military personnel and long-distance truck drivers, for interventions is believed to be most cost-effective in reducing the burden of STIs and the transmission of HIV related to STIs. 

Senegal has maintained one of the lowest rates of HIV infection in sub-Saharan
Africa and has long emphasized prevention and primary healthcare. As in Uganda and Thailand, there was a unified response to HIV from the government and religious leaders. HIV prevention was included when sex education was introduced in schools, HIV voluntary and confidential counseling and testing were made available, condoms were promoted to prostitutes and their clients, and STI care was integrated into regular primary healthcare services. As these interventions were introduced, rates of all STIs measured among pregnant women in Dakar dropped dramatically, and HIV rates have remained low.(2) 

In Thailand, rates of STIs in males decreased by over 90% at the same time that condom “non-use” declined by similar proportions. These changes parallel the dramatic decreases in HIV prevalence also seen in Thailand.(2) 

Although the degree of risk in transmitting HIV with traditional practices is unknown, female circumcision should be avoided, because it may increase the risk of sexual transmission or acquisition of HIV due to increased trauma and bleeding with sexual intercourse. 

Summary

The information we have reviewed so far shows that prevention of HIV is possible and prevention efforts have been successful in several areas with limited resources. There are a number of barriers to preventing transmission of HIV. Unfortunately, several of them affect women disproportionately. There is still an enormous stigma associated with HIV infection because of ignorance and fear. Women are often unaware of their partner’s infection status or risky behaviors and, therefore, may not realize they need to use protection during sex. Furthermore, women may be unable to negotiate safer sex practices because of sexual coercion, physical or emotional violence, or fear of abandonment because they are economically dependent on their partners. 

Studies of HIV prevention interventions have resulted in several important lessons. Although high-risk groups may be targeted for certain interventions, it is not enough to focus only on these individuals. The general population must also be involved if prevention is to succeed. In working with individuals and communities, it is important to emphasize specific risk behaviors and vulnerability, rather than specific groups, such as prostitutes or men having sex with men. The behaviors place the individual at risk, and labeling can be stigmatizing. Knowledge and awareness of HIV/AIDS and the scope of the problem are important, but not enough to prevent infection. Individuals need to recognize their own level of risk and learn skills associated with sexual negotiation. Condom promotion is an essential part of any prevention program, but long-term changes in social norms will be necessary to make condom use and other behavioral changes more acceptable. Ultimately, socioeconomic interventions are needed to reduce the vulnerability of women and girls and to protect individuals with or at risk for HIV. 

Research is now underway to try to develop more effective prevention methods for the future. These methods include topical microbicides that are effective against HIV and other sexually transmitted organisms and that can be used by women without the need for sexual negotiation and in secrecy, if necessary; effective methods of prophylaxis after high-risk sexual or nonsexual exposures; and, most important, an effective vaccine.

Next Week's Lesson: 
Counseling the HIV-Positive Client About Family Planning

References and Suggested Additional Readings

1. UNICEF, DHS surveys, 1994-1999. 
2. HIV prevention needs and successes: a tale of three countries. UNAIDS. May 2001. www.unaids.org/publications/documents/epidemiology/
   determinants/Jc535-hi.pdf
3. Sittitrai W, Phanuphak P, Barry J, et al. A survey of Thai sexual behaviour and risk of HIV infection. Int J STD AIDS (England), Sep-Oct 1994, 5(5) p377-8. 
4. Seeff LB et al. 1978. Type B hepatitis after needlestick exposure: prevention with hepatitis B immunoglobulin. Final report of the Veterans Administration Cooperative Study. Ann Intern Med 88(3):285-293.
5. Royce RA, Sena A, Cates W Jr, and Cohen MS. Sexual transmission of HIV. N Engl J Med 336:1072-8, 1997. 
6. Wang C and Celum C. Prevention of HIV. In Anderson JR (ed): A Guide to the Clinical Care of Women with HIV. DHHS, HRSA, HAB. Washington, D.C. 2001.
7. Female condom-guide for planning and programming. UNAIDS. August 2000. 
   www.unaids.org/publications/documents/care/fcondoms/
   JC301-FemCondGuide-E.pdf
8. Male condom technical update. UNAIDS. September 2000. 
   www.unaids.org/publications/documents/care/mcondoms/
   JC302-TU18-MaleCondom-E.pdf
9. Consultation on STD interventions for preventing HIV: What is the evidence? UNAIDS. May 2000. 
   www.unaids.org/publications/documents/care/general/
   ConsultSTD_E.pdf