e6-06: Prevention of Sexually Transmitted Infections in Women

Sexually transmitted infections (STIs) are common and 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 counseling to promote abstinence, postponement of sexual debut, a limited number of sexual partners, and regular latex or polyurethane condom use.

A. HPV Vaccine

Three HPV vaccines are available: a quadrivalent HPV vaccine, Gardasil, that includes capsid proteins against four HPV types (6, 11, 16, and 18); a bivalent vaccine, Cervarix (includes capsid proteins against HPV types 16 and 18); and a nine-valent vaccine, Gardasil 9 (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, Gardasil 9, is currently available. HPV vaccination is routinely recommended for all children ages 11 or 12 years. For those who do not receive vaccination at this age, all persons through age 26 years should receive HPV vaccine. Routine vaccination is not recommended for adults over age 26 but shared decision making may help identify individuals aged 27–45 years who would benefit from HPV vaccination, such as those with no or few previous sexual partners. 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.

While HPV vaccination has been shown to decrease the risk of invasive cervical cancer among vaccinated women, 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 years, 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. The Advisory Committee on Immunization Practices of the CDC also recommends vaccinating any adult who requests vaccination, regardless of the presence of an identified risk factor. Rates of hepatitis B are higher in individuals with diabetes mellitus 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 or older and for all adults requesting protection against hepatitis A (eg, travelers, health care workers). Individuals who use injection or non-injection 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 individual with infection does not have active lesions; 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 based solely on age, whereas other recommendations 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 aged 24 years or 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 non-monogamous 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 people with hepatitis B infection (USPSTF Grade B recommendation for testing).

D. Hepatitis C

The CDC recommends screening all adults over 18 years of age for hepatitis C infection at least once in a lifetime. Individuals at high risk for hepatitis C should also be screened. Risk factors include injection drug use and high-risk sexual behaviors. Hepatitis C screening is also recommended for all pregnant women during each pregnancy.

A. HIV

For women without HIV 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. Herpes Simplex Virus

Treating individuals who have genital HSV with valacyclovir once daily can reduce the risk of transmitting it to an partner without infection.

For women who experience 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 those who experience sexual assault receive a hepatitis B vaccine if they have not been previously vaccinated or do not have documented immunity. After an initial vaccine dose, 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 have hepatitis B infection, 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 three-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.