e6-06: Prevention of Sexually Transmitted Infections in Women

Sexually transmitted infections (STIs) are common, and some can lead to significant consequences. For example, chlamydia and gonorrheal infections can lead to pelvic inflammatory disease, infertility, and chronic pelvic pain. Many STIs are asymptomatic in women. Primary prevention of STIs includes promoting abstinence, postponing sexual debut, limiting number of sexual partners, and regular latex or polyurethane condom use.

A. Human Papillomavirus Vaccine

Three human papillomavirus (HPV) vaccines are available: a quadrivalent HPV vaccine that includes capsid proteins against four HPV types (6, 11, 16, and 18); a bivalent vaccine (includes capsid proteins against HPV types 16 and 18); and a nine-valent vaccine (includes capsid proteins against HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58). In the United States, only the 9 valent vaccine is currently available. These vaccines are recommended by the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention (CDC) for routine vaccination of girls, adolescents, and women aged 9–10 or 11–12 years with "catch-up" vaccinations of unvaccinated individuals up to age 26 years to prevent disease associated with these HPV types (see Table 30–7). The Advisory Committee on Immunization Practices (ACIP) also recommends routine vaccination for boys and adolescents aged 11–12 years with catch-up vaccinations up to age 26 years. Published studies show a high degree of efficacy in prevention of vaccine-associated genital warts, persistent HPV infections, and cervical intraepithelial neoplasia. Protection has not been shown against strains that are absent from the vaccine administered or against strains that had already infected an individual before vaccination. For adults age 26–45, the ACIP now recommends shared clinical decision-making regarding HPV vaccination, recognizing that some who are not adequately vaccinated may benefit.

Unanswered questions about these vaccines include their long-term effects and their duration of protection against infection. Receipt of a vaccine should not change cervical cancer screening intervals in women. For those who start the vaccine series before the age of 15, two doses are recommended, whereas for those who start the series between age 15 and 26 years, a three-dose vaccine series is recommended.

B. Hepatitis B Vaccine

Hepatitis B vaccine is routinely administered to children and adolescents aged 0–18 years. For adults who have not previously been vaccinated, individuals who are at risk for sexual or blood-borne transmission of hepatitis B should be vaccinated. Rates of hepatitis B are higher in individuals with diabetes mellitus than in the rest of the population, and outbreaks of hepatitis B have been associated with blood glucose monitoring. Hepatitis B vaccination is therefore also recommended for individuals with diabetes mellitus.

C. Hepatitis A Vaccine

Hepatitis A can also be sexually transmitted. Hepatitis A vaccination is currently recommended for all children aged 12 months and older and for all adults requesting protection against hepatitis A (eg, travelers, health care workers). Individuals who use injection or noninjection illicit drugs and those with high-risk sexual behaviors will receive greater benefit.

Consistent use of latex or polyurethane condoms by male sexual partners is one of the most effective methods of preventing STIs in women. Consistent condom use has been shown to reduce the risk of transmission of HIV by 80–95%. Other studies have shown that consistent condom use can prevent transmission of gonorrhea, chlamydia, and Trichomonas. Transmission of herpes simplex viruses (HSV) can occur even when the infected individual does not have active lesions, and thus, consistent condom use has been shown to reduce the risk of HSV transmission. Condom use also decreases risk of HPV infection. Since oil-based lubricants can weaken latex, water-based lubricants should be used with latex condoms, if lubrication is needed.

Screening for STIs in women can lead to early detection and treatment and can also reduce the risk of transmission to others. Screening is recommended for several STIs. In some cases, these recommendations are solely based on age, whereas other recommendations also incorporate STI risk factors.

A. Chlamydia and Gonorrhea

The USPSTF and the CDC recommend annual screening for Chlamydia trachomatis and Neisseria gonorrhoreae in sexually active women age 24 years and younger (see Chapter 30-06). Screening should continue in older women who have high-risk sexual behaviors, including new or multiple sex partners, inconsistent condom use in nonmonogamous relationships, previous or concurrent STIs, and exchanging sex for money.

B. HIV

The USPSTF recommends screening all women for HIV once, including all adolescents and women aged 15–65 years, and rescreening other women at high risk and all pregnant women. HIV testing should also be recommended to all patients who seek testing for, or who are found to have, an STI.

C. Hepatitis B

Women at high risk for hepatitis B infection should be screened with hepatitis B surface antigen, surface antibody, and core antibody (see Table 16–5). High-risk individuals include those born in high-prevalence areas, those with HIV infection, injection drug users, female partners of men who have had sex with men, and household contacts of hepatitis B–infected persons (USPSTF Grade B recommendation for testing).

D. Hepatitis C

The CDC recommends screening all women born between 1945 and 1965 for hepatitis C infection. Individuals at high risk for hepatitis C should also be screened. Risk factors include injection drug use and high-risk sexual behaviors.

A. HIV

For HIV-negative women who are at high risk for acquiring HIV infection, preexposure prophylaxis can be an effective method of reducing its transmission (see Chapter 31-05). There is also observational evidence that postexposure prophylaxis can decrease the risk of infection after a sexual or occupational exposure to HIV (Chapter 31-05).

B. HSV

Treating individuals who have genital HSV with valacyclovir once daily can reduce the risk of transmitting it to an uninfected partner.

For women who are victims of a sexual assault, empiric treatment of several STIs is recommended. The CDC recommends empiric treatment of gonorrhea and chlamydia with ceftriaxone 250 mg intramuscularly and azithromycin 1 g orally. In addition, they recommend either metronidazole or tinidazole 2 g orally for empiric treatment of trichomoniasis.

The CDC also recommends that victims receive a hepatitis B vaccine, if they have not been previously vaccinated or do not have documented immunity. The three-dose vaccine series should then be completed with another dose 1 month later and a third dose at 6 months. If the perpetrator is known to be hepatitis B infected, immediate administration of the hepatitis B immune globulin is also recommended. Postexposure prophylaxis for HIV infection should also be offered (see Chapter 31-05). Age-eligible individuals who have not previously received vaccination against HPV should begin a two-dose HPV vaccine series.

If a woman declines empiric treatment of STIs, then testing for gonorrhea, chlamydia, and trichomoniasis is recommended, along with blood tests for syphilis, hepatitis B, and HIV. Testing should be done as soon as is feasible after the assault, but ideally within 72 hours.