Chapter 45: Sexually Transmitted Infections in Adolescents and Young Adults

BACKGROUND

Each year, more than 15 million new cases of sexually transmitted infections (STIs) are diagnosed. Almost half of these cases are in adolescents and young adults. Despite the fact that 15- to 24-year-olds make up only one quarter of the sexually active population, they carry a heavy burden of disease. The National Health and Nutrition Examination Survey found that 25.6% of adolescents contracted at least one STI within 1 year after the start of sexual activity.¹ Surveillance data from the Centers for Disease Control and Prevention reveal that young adults aged 20 to 24 had the highest incidence of chlamydia, gonorrhea, and syphilis, and highest prevalence of human papillomavirus (HPV) in 2011.² For the majority of these infections, teens aged 15 to 19 years followed closely behind in the incidence and prevalence of STIs.

The incidence of STIs among youth has increased over the past decade. A combination of biological, behavioral, and socioeconomic factors have been cited as reasons adolescents are disproportionately affected by STIs. Higher risk has been attributed to early age at onset of sexual activity, higher number of sexual partners, and multiple concurrent partners, all leading to more exposures over time. Lack of condom use, barriers to accessing preventive services for STIs, lack of health insurance or inability to pay, confidentiality concerns, and discomfort with adult-designed healthcare services are also contributors.^1,2

Disparities by sex, race, ethnicity, and sexual behavior are also present within the adolescent population. Rates of gonococcal and chlamydial infections are consistently higher in women than men. This difference is attributable to increased screening of women as well as to the often asymptomatic presentation of disease in men. Young men who have sex with men (YMSM) have higher incidence rates of HIV and primary and secondary syphilis and make up a disproportionate number of the new cases of syphilis, chlamydia, and gonorrhea. Data from 2005 to 2011 showed that men who have sex with men (MSM) were 60 times more likely than men who have sex with women to be diagnosed with syphilis and 95 times more likely than women.³ Racial and ethnic minorities also have disproportionately higher STI prevalence rates. According to the National Longitudinal Study of Adolescent to Adult Health study, African American adolescents had chlamydia rates 6 times higher than white adolescents, and gonorrhea prevalence was 36 times higher in African American males and 14 times higher in African American females compared to their respective Caucasian peers.¹ Similar discrepancies exist for trichomoniasis, chlamydia, herpes simplex virus (HSV), and syphilis. Of note, African American adolescents have actually been found to have lower risk behavior scores (number of reported partners, use of alcohol, tobacco, and drugs, etc.) than their Caucasian counterparts, and yet are still up to 29 times more likely to have an STI.¹ More work is needed to determine the source for these disparities, which are clearly not based on individual risk behavior alone.