According to the Centers for Disease Control and Prevention's (CDC) 2005 Youth Risk Behavior Surveillance survey, nearly one-half of US high school students report ever having had sexual intercourse.1 Over 60% of high school seniors report a history of sexual intercourse, while 20% of seniors report having had at least four sexual partners. Even higher numbers of adolescents engage in other, noncoital sexual behaviors, including oral sex.2–4 Young people age 15–24 years old make up one-fourth of sexually active individuals in the United States, yet acquire nearly one-half of all new sexually transmitted infections (STIs) each year.5 Sexually active adolescents are at high risk for contracting STIs for a variety of reasons. While many adolescents report the use of condoms, they are not necessarily using them consistently or correctly.6,7 They are more likely than adults to experiment with multiple sexual partners,8–10 to engage in riskier sex while under the influence of alcohol or drugs,8,11 to have a poor understanding of STI transmission and consequences of infection,12 and to face barriers to accessing confidential health care.13,14 In addition, the presence of columnar epithelial cells in the cervical ectropion of female adolescents increases susceptibility to infection with certain sexually transmitted organisms.
This chapter will focus on four sexually transmitted genital infections commonly found in the adolescent population. Three of these infections—chlamydia, trichomoniasis, and human papillomavirus (HPV)—together account for nearly 90% of new STIs among 15–24-years-old youth.15 Gonorrhea, the second most common infection reported to the CDC and a significant risk factor for chronic reproductive health problems, will be discussed in the section with chlamydia as a major cause of cervicitis and urethritis in teenagers.
Chlamydia is the most frequently reported STI in the United States, with an estimated 3 million cases annually. At least 70% of genital chlamydia infections are in adolescents and young adults, 15–24 years old.5 CDC surveillance data has repeatedly shown infection rates to be highest in 15–19-years-old females. In 2005, the rate of chlamydia infection in adolescent females (15–19 years old) was nearly 2,800 per 100,000 population.16 Rates in males are highest for 20- to 24-year olds, with 805 per 100,000 population, followed next by males 15- to 19-year olds (505 per 100,000 population). This reflects common patterns of partnering, in which adolescent women are more commonly engaging in sex with slightly older males.
Gonorrhea, the second most common reportable disease, has infection rates similar in distribution to those of chlamydia infections. In 2005, adolescents aged 15–19 years had the highest reported rates of gonorrhea among women, with reported rates of 625 per 100,000 population.16 Rates in males are highest for 20- to 24-year olds, with 437 per 100,000 population, followed next by 15- to 19-year-old males, with 261 per 100,000 population.