STI/HIV prevention methods

Prevention and control of STDs is based on five key concepts: first, educating individuals at risk to prevent STD infection; second, identifying asymptomatically infected individuals or those who have symptoms of STDs but are unlikely to seek medical care; third, providing effective diagnosis and treatment of infected individuals; fourth, testing, treating, and counseling sexual partners of individuals with STDs; and fifth, providing preventive vaccination to individuals at risk. Although this document focuses primarily on secondary prevention, that is, the clinical aspects of STD control, the primary means of preventing STDs is through changes in sexual behavior. Moreover, since STD control reduces the likelihood of transmission to a partner, prevention of STD infection in individuals results in prevention of disease in the community as a whole.

Physicians and other health care workers play an important role in preventing STDs. In addition, when treating patients with STDs caused by bacteria or protozoa to interrupt further transmission, clinicians have the opportunity to educate and counsel patients and to participate in the identification and treatment of infected sexual partners. The ability of health care workers to obtain an accurate sexual history is essential to preventive care. Guidance on this topic is provided in the Sexuality and Reproductive Health section of the Contraceptive Technology guide. Accurate diagnosis and timely reporting by physicians are essential to effective surveillance.

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Recommendations for patients on the prevention of STDs

Preventing the spread of STDs requires that individuals at risk of transmitting or acquiring the disease change their behavior. The first necessary step is to include appropriately worded questions about the patient's sexual history when taking the medical history. Once risk factors have been identified, the health care provider can provide recommendations for preventing STDs. Effective recommendations require communication skills (e.g., the ability to be respectful, compassionate, and nonjudgmental). Effective communication techniques include using open-ended questions, using terms that the patient understands, and reassuring the patient that treatment will be provided regardless of his or her ability to pay, citizenship, immigration status, language spoken, or lifestyle.

The interview should take into account the patient's specific risk factors. Specific actions the patient should take to avoid getting or spreading an STD (including not having sex if he or she has symptoms of an STD) should be described.

Sexually transmitted infection

The most effective way to prevent sexual transmission of HIV and other STIs is to abstain from sexual intercourse with infected partners. Abstinence from penetrative sexual intercourse should be strongly recommended for individuals who are being treated for STIs or whose partners are being treated for STIs, and for individuals who wish to avoid the consequences of sexual intercourse (i.e., STI/HIV infection and pregnancy). A more detailed discussion of abstinence is provided in Contraceptive Technology.

• Both partners should be tested for STIs and HIV before engaging in sexual activity.
• If a person chooses to have sex with a partner whose infection status is unknown, or with someone who is infected with HIV or another STI, he or she should use a new latex condom for each act of sex.

Intravenous drug users

Recommendations for intravenous drug users (IDUs) are as follows:

• Begin or continue a drug addiction treatment program.
• Under no circumstances should you use injection equipment (syringes, needles) if they have already been used by another person.
• If there is a needle exchange program in the area, clean needles should be obtained.
• People who continue to use syringes or needles that have already been used should first clean them with bleach and water. (Disinfection with bleach does not sterilize equipment and is not guaranteed to inactivate HIV. However, routine cleaning of injection equipment will reduce HIV transmission if the equipment is shared by different people.)

Preventive vaccination

Preventive vaccination is one of the most effective methods of preventing the transmission of certain STDs. Hepatitis B virus infection is often transmitted sexually, and hepatitis B vaccination is recommended for all unvaccinated patients being tested for STDs. Two hepatitis A vaccines have recently been licensed in the United States. Hepatitis A vaccination is recommended for several groups of patients who may attend an STD clinic, including gay and bisexual men and people who use drugs. Vaccines against other STDs are being tested and may be available in the next few years.

Methods of preventing STDs/HIV

Male condoms

When used consistently and correctly, condoms are highly effective in preventing a variety of STIs, including HIV infection. Numerous cohort studies, including studies of serodiscordant couples, have shown a significant protective effect of condoms against HIV infection. Because condoms do not cover all surfaces at risk of infection, they are more effective in preventing infections transmitted by mucosal contact than by skin-to-skin contact. Condoms are classified as medical devices and are tested by the FDA. The integrity of every latex condom manufactured in the United States is tested electronically before packaging. In the United States, the incidence of condom breakage during use is low (2 in 100). Condom failures are usually the result of inconsistent or incorrect use, rather than condom breakage.

To effectively prevent STIs, patients should be advised to use condoms consistently and correctly. Patients should also be instructed on how to use a condom correctly. The following guidelines will help ensure that the male condom is used correctly:

• Use only a new condom each time you have sex.
• Handle the condom carefully to avoid damage from nails, teeth or other sharp objects.
• Put a condom on the penis in a state of erection and before any genital contact with a partner.
• Make sure there is no air at the end of the condom.
• Make sure you have enough lubrication during intercourse, and may need to use additional lubricants.
• Use only water-based lubricants (such as KY Jelly™ or glycerin) with latex condoms. Do not use oil-based lubricants (such as petroleum jelly, mineral oils, massage creams, body lotions, or cooking oils) as they will degrade the latex.
• To avoid slipping after intercourse, hold the condom firmly at the base of the penis when removing it and remove it while the penis is erect.

Female condoms

Laboratory studies have shown that the female condom (Reality™)—a lubricated polyurethane sheath with a ring at both ends that is placed in the vagina—is an effective mechanical barrier to viruses, including HIV. Aside from small studies in trichomoniasis, clinical studies evaluating the effectiveness of female condoms in preventing HIV and other STIs are incomplete. When used consistently and correctly, female condoms should significantly reduce the risk of STIs. In situations where a male condom cannot be used, a couple should use a female condom.

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Condoms and spermicides

There is no evidence that condoms lubricated with spermicides are more effective in preventing the transmission of HIV and other STIs than condoms with any other lubricant. In addition, the use of condoms coated with spermicides has been associated with urinary tract infection with Echehchia coli in young women. There is no evidence that the use of condoms with spermicide application is more effective than the use of condoms without spermicides. Therefore, correct use of condoms without lubricants, as well as with spermicidal lubricants or with spermicide inserted into the vagina, is recommended.

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Vaginal spermicides, sponges and diaphragms

Vaginal spermicides used without a condom have been shown to reduce the risk of cervical gonorrhea and chlamydia in several randomized, controlled trials. However, they do not provide protection against HIV infection, and spermicides are not recommended for use in HIV prevention. Vaginal contraceptive sponges provide protection against cervical gonorrhea and chlamydia, but their use increases the risk of candidiasis. Diaphragms have been shown to provide protection against cervical gonorrhea, chlamydia, and trichomoniasis, but only in cross-sectional and case-control studies; no cohort studies have been conducted. Vaginal spermicides, sponges, or diaphragms should not be used to protect women from HIV infection. The role of spermicides, sponges, or diaphragms in preventing STIs in men has not been studied.

Non-barrier contraception, surgical sterilization, hysterectomy

Women who are not at risk of becoming pregnant may incorrectly believe that they cannot become infected with STIs, including HIV. Non-barrier methods of contraception do not protect against STIs or HIV. Hormonal contraceptives (oral contraceptives, Norplant, Depo-Provera) have been associated with increased rates of cervical STIs and HIV infection in several cohort studies, but not all studies have confirmed these findings. Women using hormonal contraception (oral contraceptives, Norplant™, Depo-Provera™) who have had surgical sterilization or hysterectomy should be counseled about condom use and their risk of STIs, including HIV infection.

HIV prevention counseling

Finding out the HIV status and providing appropriate counseling plays an important role in motivating behavior change. Therefore, HIV prevention counseling is considered a very important intervention in the HIV prevention strategy, although its effectiveness in reducing risk behavior cannot be accurately assessed. By ensuring that counseling is successful and the patient is properly oriented, the health care provider will be able to correctly assess the patient’s risk level and help him or her develop an individual and realistic HIV prevention plan.

HIV testing counselling consists of two main phases: pre-test and post-test counselling. During pre-test counselling, the health care provider should assess the patient’s individual risk, explain the meaning of positive and negative test results, obtain informal consent for testing, and help the patient develop a realistic, personalised risk reduction plan. During post-test counselling, the health care provider should inform the patient of the test results, explain the meaning of the findings, and explain prevention recommendations. If the test result is positive, post-test counselling should discuss referral to follow-up care and, if appropriate, social and psychological services. For HIV-seronegative patients who remain at risk of acquiring HIV, referral to other counselling or prevention services may also be helpful.

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