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O'Connor E, Lin JS, Burda BU, et al. Behavioral Sexual Risk Reduction Counseling in Primary Care to Prevent Sexually Transmitted Infections: An Updated Systematic Evidence Review for the U.S. Preventive Services Task Force [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2014 Sep. (Evidence Syntheses, No. 114.)

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Behavioral Sexual Risk Reduction Counseling in Primary Care to Prevent Sexually Transmitted Infections: An Updated Systematic Evidence Review for the U.S. Preventive Services Task Force [Internet].

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Condition Definition

Sexually transmitted infections (STIs) are infections that are primarily transmitted through sexual contact (e.g., vaginal, anal, or oral intercourse).1 The STIs with the most substantial public health impact in the United States include human immunodeficiency virus (HIV), hepatitis B virus infection (HBV), herpes simplex virus (HSV) 1 and 2, human papillomavirus (HPV), Chlamydia trachomatis, Neisseria gonorrhea, Treponema pallidum (syphilis), and Trichomonas vaginalis. Other STIs include bacterial vaginosis (BV), granuloma inguinale, chancroid, pubic lice, and Sarcoptes scabiei var. hominis (scabies).

Prevalence and Burden

The Centers for Disease Control (CDC) estimate that approximately 20 million new cases of STIs occur each year in the United States and more than two thirds of those cases are among persons ages 15 to 24 years.2 Point prevalence for any of the five most common STIs among females ages 14 to 19 was 24 percent in 2003 to 2004, and 38 percent among those who were sexually active.3 In 2010, the inflation-adjusted annual direct medical costs of STIs (including HIV) were $16.9 billion in the United States.4

Bacterial Infections


In 2011, 1,412,791 cases of Chlamydia trachomatis infection were reported to the CDC. This represents the largest number of cases ever reported to the CDC for any condition and is an 8 percent increase from the rate in 2010. This rate reflects an overall rate in U.S. women (648.9 cases per 100,000 females) that is more than 2.5 times greater than the rate in men (256.9 cases per 100,000 males). In 2011, the age-specific rates of chlamydia in women were highest among those ages 15 to 19 years (3,416.5 cases per 100,000 females) and 20 to 24 years (3,722.5 cases per 100,000 females). In 2011, age-specific rates in men were highest among those ages 20 to 24 years (1,343.3 cases per 100,000 males).5

Chlamydial infections can result in pelvic inflammatory disease (PID) in women, which is a major cause of infertility, ectopic pregnancy, and chronic pelvic pain. Chlamydial infection can also facilitate HIV transmission. Pregnant women infected with chlamydia can transmit the infection during delivery, which can result in neonatal ophthalmia and pneumonia.5


In 2011, 321,849 cases of gonorrhea were reported in the United States (104.2 cases per 100,000 population), with the highest rates occurring in the southern United States. Gonorrhea rates were slightly higher among women (108.9 cases per 100,000) than men (98.7 cases per 100,000). In 2011, gonorrhea rates were highest among females ages 20 to 24 years (584.2 cases per 100,000) and 15 to 19 years (556.5 cases per 100,000). In men, the rate of gonorrhea was highest among those ages 20 to 24 years (450.6 cases per 100,000).

Gonococcal infections, like chlamydial infections, can cause PID in women. Treating gonorrhea is complicated by antimicrobial resistance in the United States, as the only class of antibiotics recommended for the treatment of gonorrhea is cephalosporins.5


In 2011, the overall reported cases of primary and secondary syphilis in the United States was 13,970. Primary and secondary syphilis rates are higher among men (8.2 cases per 100,000) than women (1.0 case per 100,000). Syphilis rates are highest among adults ages 20 to 24 years (13.8 cases per 100,000) and 25 to 29 years (12.1 cases per 100,000).

As with chlamydia, syphilis facilitates the transmission of HIV infection. If untreated, early syphilis in pregnant women results in perinatal death in up to 40 percent of cases. If acquired during the 4 years prior to pregnancy, untreated syphilis can lead to infection of the fetus in 80 percent of cases. Transmission of syphilis to the fetus during pregnancy can result in fetal death or an infant born with physical and mental developmental disabilities. The rate of congenital syphilis was 8.7 cases per 100,000 live births in 2010.5 This rate represented a decrease since 2008 (from 10.5 cases per 100,000 live births).

Viral Infections


About 1.2 million people in the United States are living with HIV infection, and one in five are unaware of their infection. Since the HIV epidemic began, an estimated 1,129,127 persons in the United States have been diagnosed with acquired immunodeficiency syndrome (AIDS) and 619,400 have died.6 In 2009, the estimated rate of HIV diagnoses in the 40 states with confidential name-based reporting systems was 17.4 per 100,000 persons. In 2009, adults ages 20 to 24 years represented the highest rate of diagnoses (36.9 per 100,000 population). African Americans accounted for 52 percent of all diagnoses of HIV infection and males accounted for 76 percent among adults and adolescents. In 2009, most new infections were attributed to sexual contact, either male-to-male (57%) or heterosexual contact (31%).7 Persons with other STIs have increased risk for transmission and acquisition of HIV. Persons with current STIs are at least 2 to 5 times more likely than uninfected persons to acquire HIV if exposed through sexual contact. Additionally, persons with HIV infection who are also infected with other STIs are more likely to transmit HIV through sexual contact than those who are not infected with other STIs.8

The rate of HIV transmission has declined by an estimated 89 percent since the mid-1980s, attributable to HIV prevention efforts, which have saved an estimated $125 billion in medical costs.9


HPV is a common STI. Researchers have estimated that at least 50 percent of sexually active persons will acquire an HPV infection in their lifetime.1 Data from 2003 to 2005 indicate an overall prevalence of 23 percent for high-risk HPV (types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68) in the United States. HPV prevalence was highest in females ages 14 to 19 years (35%) and 20 to 29 years (29%).5 Persistent infection with high-risk HPV can lead to the development of cervical cancer as well as other anogenital and throat cancers. Other HPV strains are associated with genital warts. Although HPV vaccines do exist, HPV is not treatable once acquired. Many women have transitory infections that are spontaneously cleared by the immune system.

HSV 1 and 2

Between 2005 and 2008, 16.2 percent of persons in the United States ages 14 to 49 years had an HSV-2 infection. The overall prevalence of genital herpes, however, is likely higher because an increasing number of genital herpes infections are caused by HSV-1.10 HSV-2 infection is more prevalent among women (20.9% in females ages 14 to 49 years) than men (11.5% in males ages 14 to 49 years). Most persons with HSV-1 or HSV-2 infection are asymptomatic or have very mild symptoms that may go unnoticed or are mistaken for another skin condition. Nearly 82 percent of persons with HSV-1 or HSV-2 are unaware of their infection. Genital herpes can cause painful ulcers on the genitals that can be particularly severe and persistent in persons with suppressed immune systems. These lesions may also appear in the buttocks, groin, thighs, fingers, and eyes during the course of infection. Persons with genital herpes have an estimated 2- to 4-fold increased risk for acquiring HIV if exposed to that infection. Pregnant women can transmit herpes infection to their child, which can result in a potentially fatal infection in the offspring (neonatal herpes). The risk for perinatal transmission is higher during the first outbreak of symptoms (e.g., blisters) than during a recurrent outbreak. Rarely, HSV-1 and HSV-2 can also cause blindness, encephalitis, and aseptic meningitis.11


In the United States, between 4.3 and 5.6 percent of the population has been infected with HBV at some point during their lives. Between 800,000 and 1.4 million persons in the United States are living with a chronic HBV infection. From 2004 to 2009, the annual number of chronic liver disease deaths associated with HBV was 3,000. In 2009, the estimated total number of new HBV infections was 38,000.12 The proportion of reported cases attributed to sexual contact is unknown.13 Effective HBV vaccines have been available in the United States since 1981.13

Parasitic Infections


An estimated 3.7 million persons in the United States have a trichomoniasis infection. Trichomoniasis infection is more common in women than men. The prevalence of Trichomonas vaginalis infection in the United States is estimated to be 2.3 million (3.1%) among females ages 14 to 49 years. This estimate is based on a sample of women who participated in the National Health and Nutrition Examination Survey from 2001 to 2004. Only about 30 percent of persons with the infection develop any symptoms. Untreated trichomoniasis can cause genital inflammation that facilitates HIV infection or transmission. Pregnant women with trichomoniasis are more likely to have preterm delivery, and babies born to these women are more likely to have low birth weight. Pregnant women represent 3.2 percent of all infections.14

Etiology and Natural History

According to 2006 to 2012 data from the National Survey of Family Growth, the average age at first vaginal heterosexual intercourse for women and men was 17.1 years.15,16 In another study using data from 2007 to 2012, 66 percent of men and women experienced their first oral sexual encounter between the ages of 15 and 24 years.17 Initiation of oral sex commonly occurs before first vaginal sexual intercourse. According to the National Longitudinal Study of Adolescent Health, younger age at first intercourse is associated with higher odds of STI infection compared with older ages at first intercourse.18

While the time from sexual initiation to first STI diagnosis has not been widely studied, one cohort study of 386 adolescent females ages 14 to 17 years who initiated first sexual intercourse at an average age of 14.2 years found that diagnosis of the first STI occurred a median of 2 years after first intercourse.19 The median time to reinfection was 1.2 years.

While some infected persons may experience no symptoms of the STI, they are still infectious. For example, nearly 70 percent of men and women with a gonococcal or chlamydial infection experience no symptoms.20 Untreated STIs can lead to serious adverse health outcomes (e.g., infertility, PID, reinfection). Reinfection is also common, especially with gonorrhea, chlamydia, and trichomoniasis. A 2007 systematic review of repeat gonococcal and chlamydial infection among males reported a median rate of reinfection within 12 months of initial diagnosis of 11.3 and 7.0 percent, respectively.21 A companion 2009 systematic review among females reported a median rate of reinfection within 12 months of initial diagnosis of 13.9 and 11.7 percent, respectively.22

The incubation and latency periods between infection, first symptoms, and serious sequelae varies by STI and specific health outcome. The incubation period of gonococcal infection to first symptoms, for example, can be as short as 2 days after exposure. Acute hepatitis can occur within 4 to 24 weeks after HBV exposure. The latency period from HPV infection to manifestation into a precancerous lesion of the cervix, on the other hand, may take as long as 20 years. Since there is no cure for some STIs, prevention and early treatment are critical to averting individual- and population-level adverse health outcomes and spread of disease.

Risk Factors

Risky sexual behaviors can include inconsistent or improper use of barrier contraception, high number of lifetime sex partners, multiple sex partners, sexual intercourse under the influence of mind-altering substances, and sexual intercourse with a partner who has an STI or is at high risk for an STI.

Incidence and prevalence of STIs are elevated in a number of populations in the United States, which increases the risk for exposure. African Americans have the highest risk for STI infection of all racial/ethnic groups. For example, incidence rates of STIs tracked by the CDC are consistently 8 or more times higher in African Americans than whites,23 and African American youth accounted for 57 percent of all new HIV infections among persons ages 13 to 24 years in 2009.24 Other racial/ethnic groups with a high prevalence of STIs are American Indians/Alaska Natives and Hispanics.23 Young persons (age <25 years) are also at higher risk for STIs than those age 25 years or older.23 STI incidence also varies by region within the United States, with highest rates in the southeast and Alaska.23 Other populations with high STI rates include men who have sex with men (MSM),25 persons with low income living in urban settings,26 military recruits,27 persons with mental illness or disability,28 current or former inmates,29 current or former intravenous drug users,30 persons with a history of sexual abuse,31 and persons engaging in transactional sex.32,33

While most STIs occur in young adults, there is growing concern about STIs in older adults, as recent epidemiological studies show sharp increases in STI rates among those age 50 years or older.34 According to 2008 CDC data, 15 percent of new HIV diagnoses occurred in persons age 50 years or older.35 In another study, also based on CDC data, the rates of syphilis and chlamydia increased 43 percent from 2005 to 2009 in adults age 55 years or older.36 The increase in STI rates among adults age 50 years or older may be attributable to limited sexual health services, increased longevity, and the availability of sexual performance enhancement drugs.34

Sexual Health History and Risk Assessment

Primary care physicians have an opportunity to assess a patient's risk for acquiring STIs during the patient visit. A comprehensive sexual health history assesses the patient's sexual activity and other related behaviors that increase their risk for an STI and becoming pregnant.37 Important items in a sexual health history include sexual orientation (i.e., sexual preference), frequency of sexual activity and the number of partners, and type of sexual engagement (e.g., penile-vaginal intercourse, oral sex, anal sex).37 Several national organizations, including the American Academy of Pediatrics, the American Academy of Family Physicians, the American Congress of Obstetrics and Gynecology, the Society for Adolescent Health and Medicine, the American Medical Association, and the Institute of Medicine recommend that physicians periodically obtain a sexual history or sexual risk assessment and discuss risk reduction with all patients. Many of the aforementioned professional organizations have developed sexual history taking or sexual risk assessment tools for providers to use in primary care.

Counseling Interventions to Prevent STIs

The CDC recommends that health care providers inform patients on how to reduce their risk for STI transmission, including abstinence, correct and consistent condom use, and limiting the number of sex partners. It recommends an interactive, empathic, and nonjudgmental approach that is tailored to the patient's personal risk, with personalized goal setting.1 The CDC maintains a Web site of interventions it considers effective for HIV risk reduction, including more than 25 behavioral interventions tailored for a variety of different populations.38 These interventions commonly include motivational and cognitive behavioral elements, such as goal setting, skills development with role play, communication or negotiation training, values clarification exercises, and problem solving.

Current Clinical Practice in the United States

Representative surveys examining STI counseling practices among U.S. physicians have varied findings. In a survey of 508 pediatricians, for example, only 28 percent offered sexual risk reduction guidance to the parents of their adolescent patients.39 In another survey conducted among 1,217 Californian internists, family physicians, obstetricians-gynecologists, and pediatricians, 31 percent reported educating their adolescent patients about STI/HIV transmission and 36 percent reported educating their sexually active adolescent patients.40 Among 541 surveyed Pennsylvania primary care physicians, 88% reported asking their adolescent and young adult patients (ages 15 to 25 years) about sexual activity and 80 percent reported counseling those patients about STI/HIV transmission and prevention.41 In the same study, however, 70 percent of physicians believed STI counseling in general to be ineffective. Primary care physicians frequently reported insufficient time as the main barrier to providing STI and/or HIV counseling during a patient visit.41-45 National data from the Youth Adult Health Care Survey indicate that nearly half of adolescents reported that they did not receive guidance on various age-appropriate topics, including sexual activity, contraception, and STIs, during their previous health examination.46

Rates of STI counseling are higher among physicians working in STI clinics—81 percent reported counseling and 25 percent specifically developed a risk reduction plan with the patient.47

Current Initiatives in the United States

In 2001, the U.S. Surgeon General issued a call to action to promote sexual health and responsible sexual behavior.48 These strategies included increasing awareness, implementing and strengthening interventions, and expanding the research base relating to sexual health matters. In 2007, the CDC Division of STD Prevention released a strategic plan to provide national leadership, research, policy development, and scientific information to help Americans live safer, healthier lives through the prevention of STIs and their complications.49 The seven strategic goals included:

  • Preventing STI-related infertility
  • Preventing STI-related adverse outcomes of pregnancy
  • Preventing STI-related cancers
  • Preventing STI-related HIV transmission
  • Strengthening STI prevention capacity and infrastructure
  • Reducing STI health disparities across and within communities and populations
  • Addressing the effects of the social and economic determinants and costs of specific STIs and associated sequelae among specific populations.

Currently, the CDC has two initiatives to inform the public and reduce or eliminate STIs: the Syphilis Elimination Effort and the Infertility and Prevention Project, which promotes screening for chlamydia and gonorrhea.50 The Healthy People 2020 initiative51 has published 10 goals related to reducing the proportion of adolescents and young adults with chlamydia, gonorrhea, syphilis, HPV, and HSV-2.

Recommendations from other health organizations for STI counseling in clinical practice are listed in Table 1.

Table 1. Recommendations of Other Organizations for Sexual Risk Reduction Counseling to Prevent STIs.

Table 1

Recommendations of Other Organizations for Sexual Risk Reduction Counseling to Prevent STIs.

Related U.S. Preventive Services Task Force Recommendations

The U.S. Preventive Services Task Force (USPSTF) has issued several recommendations related to screening for STIs. While specific details vary, the USPSTF generally recommends that primary care physicians: 1) screen sexually active, nonpregnant women at increased risk for STIs for chlamydia, gonorrhea, HIV, and syphilis; 2) screen all pregnant women for HBV, HIV, and syphilis and screen pregnant women at increased risk for STIs for chlamydia and gonorrhea; 3) screen all men for HIV and screen sexually active men at increased risk for STIs for syphilis; and 4) do not screen men and women who are not at increased risk for STIs, except for HIV.52

Previous USPSTF Recommendation

In 2008, the USPSTF concluded there was moderate certainty that high-intensity behavioral counseling interventions targeted to sexually active adolescents and adults at increased risk for STIs have a moderate net benefit on the incidence of STIs. Therefore, the USPSTF recommended high-intensity behavioral counseling for all sexually active adolescents and for adults at increased risk for STIs (B recommendation). The evidence was insufficient to assess the balance of benefits and harms of behavioral counseling to prevent STIs in nonsexually active adolescents and in adults not at increased risk for STIs (I statement).


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