Sexually transmitted diseases


Sexually transmitted diseases (STDs) are viral and bacterial infections passed from one person to another through sexual contact.


Adolescence is a time of opportunities and risk when many health behaviors are established. Although many of these behaviors are health-promoting, some are health-compromising, resulting in increasingly high rates of adolescent morbidity and mortality. For example, initiation of sexual intercourse and experimentation with alcohol and drugs are normative adolescent behaviors. However, these behaviors often result in negative health outcomes such as the acquisition of STDs. As a consequence of STDs, many adolescents experience serious health problems that often alter the course of their adult lives, including infertility, difficult pregnancy, genital and cervical cancer , neonatal transmission of infections, and AIDS (acquired immunodeficiency syndrome).

Examples of STDs with high prevalence among sexually-active adolescents include:

  • Gonorrhea: Caused by the bacteria Neisseria gonorrhoeae , gonorrhea infects the reproductive tract of women, causing pelvic inflammatory disease (PID), a major cause of infertility. The bacteria are found in vaginal secretions and semen.
  • Chlamydia: The bacteria that causes chlamydia, Chlamydia trachomatis , trigger inflammation of the reproductive tract, leading to PID in women and epididymitis (inflammation of the epididymis) in men.
  • Syphilis: Treponema pallidum is the bacteria that causes syphilis. The course of syphilis is broken down into four distinct segments: primary syphilis, occurring within a few weeks or months of initial exposure; secondary syphilis, occurring generally between six weeks and six months of initial exposure; latent syphilis, an asymptomatic period which may stretch for years; and late syphilis, the most serious stage. If left untreated, syphilis can infect a number of organ systems and cause serious complications.
  • Herpes simplex virus: Two different types of HSV (HSV-1 and HSV-2) cause lesions on the genitals, although HSV-2 is associated with the majority of cases. (HSV-1 is most commonly associated with oral lesions, or "cold sores.")
  • Human papillomavirus (HPV): HPV causes condylomata acuminata, more commonly known as venereal warts or genital warts. The warts may affect any of the external and internal genital organs in men and women.
  • Human immunodeficiency virus (HIV). HIV is the causative agent of acquired immune deficiency syndrome (AIDS), a potentially fatal condition in which the immune system fails and the individual becomes prone to frequent and unusual infections.


The mode of transmission varies among the different sexually transmitted diseases. Some bacteria or virus are found in vaginal secretions or semen (e.g. HIV and gonorrhea), while others are shed from the skin of and around the genitals (e.g. HSV and HPV). Infection typically occurs during sexual intercourse or when the genitals come into close contact. Infection may also occur during oral sex, such as transmission of HSV from an oral lesion to the genitals or vice versa, or transmission of HIV from genital secretions through a cut in the mouth. STDs may be transmitted during nonconsensual sex acts such as rape or molestation.

The transmission of many STDs is more efficient from men to women than from women to men. For example, with just one unprotected sexual encounter with an infected partner, a woman is twice as likely as a man to acquire gonorrhea or chlamydia. In addition, different STDs have different rates of transmissibility. For example, with one exposure of unprotected sexual intercourse, a woman has a 1 percent chance of acquiring HIV, a 30 percent chance of acquiring herpes, and 50 percent chance of contracting gonorrhea if her partner is infected.


STDs among sexually experienced adolescents occur at alarmingly high rates. One-fourth of the estimated 12 million new cases reported annually occur among adolescents between 15 and 19 years of age. Moreover, since many STDs are asymptomatic, they are often undiagnosed and untreated, thus increasing their potential for proliferation among adolescents.

Gonorrhea and chlamydia, the most prevalent bacterial STDs, disproportionately affect adolescents. The rates of gonorrhea in adolescents ages 15 to 19 years declined between 1990 and 2004, but in the early 2000s they continue to be higher than rates for any five-year age group between 20 and 44 years, particularly among women and African Americans.

Numerous prevalence studies for chlamydia have shown rates to be highest among adolescents and young adults under 25 years of age, many of whom are minorities. Rates of chlamydia reported by gender indicate that women, overall, have higher rates than men due in large part to increased efforts in screening women for asymptomatic chlamydial infections. The low rates of chlamydia for men suggest that the sexual partners of women diagnosed with chlamydia are not being diagnosed or treated. Chlamydia has been detected in more than 10 percent of sexually experienced women during screening.

While rates of syphilis declined between 1990 and 2004, the disease continues to be an important cause of sexually transmitted infection. The rate of syphilis infection among adolescents ages 15 to 19 is 1.3 per 100,000 population for males and 2.2 per 100,000 population for females. For comparison, the syphilis rates among males 20 to 24 is 5.5 per 100,000, and among females of the same age, 3.3 per 100,000.

HSV and HPS occur at alarming rates among sexually experienced adolescents. Studies indicate that one in six Americans is infected with HSV-2, reflecting a ninefold increase between 1975 and 2005. Prevalence of HSV-2 in adolescents and young adults varies by the demographic and behavioral characteristics of the populations studied as well as the diagnostic methods used. As of the early 2000s approximately 4 percent of Caucasians and 17 percent of African Americans are infected with HSV-2 by the end of their teenage years. One study of young pregnant women of low income status found an HSV-2 infection rate of 11 percent in women 15 to 19 years of age and 22 percent in women 25 to 29 years of age.

In 2002, there were 4,785 reported cases of AIDS among teenagers between the ages of 13 and 19, more than double the 1994 figures. Most adolescents with AIDS were infected as a result of high risk sexual and substance use behaviors. Among adolescents ages 13 to 19 years infected with HIV, 49 percent are male and 51 percent are female. Studies also indicate that African-American and Latino teens are overrepresented among persons with AIDS relative to their proportion in the population. Although these epidemiological statistics on AIDS in the United States provide a descriptive overview of the prevalence and patterns of HIV exposure in adolescents, the extent of asymptomatic HIV infection remains largely unknown.

Causes and symptoms

The chance for adolescents of getting and transmitting STDs is affected by complex interrelationships between key factors (sociodemographic, biologic, psychosocial, and behavioral). For example, many STD-related risk markers (e.g. age, gender, race/ethnicity) correlate with more fundamental determinants of risk status (e.g., access to health care, living in communities with high prevalence of STDs) to influence adolescents' risk for STDs.

Developmental factors such as pubertal timing, self-esteem , and peer affiliation may also increase their risk of exposure to STDs. An assessment of these interrelationships is critical to preventing and controlling STDs in adolescents. Moreover, since behavior is the common means by which STDs occur, an important first step in fighting STDs is to understand the prevalence and patterns of risk behaviors as well as the psychosocial context in which these behaviors occur.

Behavioral factors

Although biologic factors play an important role in the transmission of STDs, it is also the health-risking behaviors of adolescents that place them at increased risk for exposure to STDs. Behavioral risk factors include the age of sexual activity, number of sexual partners, use of contraceptives, and use of alcohol and drugs.

SEXUAL ACTIVITY Early initiation of sexual intercourse has been associated with high-risk sexual activities, including ineffective use of contraceptives, multiple sex partners over a short period of time, high-risk sex partners, and acquisition of STDs and their consequences of cervical cancer and dysplasia. The average age of first sexual intercourse is between 16 and 17 years for adolescent men and between the age of 17 and 18 years for adolescent women, and has been found to be as young as age 12 in some high-risk populations. Research on adolescents' decision to initiate sexual intercourse indicates an interaction between biological and social factors. However, much remains unknown about the interactions between hormones, behavior, and social factors.

The Youth Risk Behavior Surveillance System (YRBSS), a self-reported survey of a national representative sample of high school students in grades nine to 12, indicated that in 2003, 46.7 percent of the students reported having had sex. By grade level, the rates were 32.8 percent for ninth grade, 44.1 percent for tenth grade, 53.2 percent for eleventh grade, and 61.6 percent for twelfth grade. Approximately 7.4 percent of students reported having sex for the first time before age 13. Prevalence rates of sexual experience differed by race/ethnicity and gender. African-American students were significantly more likely (73.8% of males and 60.9% of females) than Caucasian (40.5% of males and 43.0% of females) and Hispanic (56.8% of males and 46.4% of females) students to have engaged in sexual intercourse. Moreover, data from the National Survey of Family Growth (NSFG), a large-scale national survey of women ages 15 to 44 years, reveal that family income is associated with adolescents' protection against HIV and many other STDs; adolescents from poor and low-income families are more likely to report an earlier age of sexual experience than their counterparts from higher income families.

In addition to early sexual activity, many adolescents have multiple sex partners within a short period of time in a pattern of serial monogamy which also increases their risk of acquiring STD for two important reasons: it increases the likelihood of being exposed to a sexually transmitted pathogen, and it may reflect poor choices of sexual partners. Among the sexually experienced high school students responding to the YRBSS, 14.4 percent reported having four or more sex partners. Multiple sex partners were noted more frequently among African-American students (41.7% of males and 16.3% of females), compared to Hispanic (20.5% of males and 11.2% of females) and Caucasian (11.5% of males and 10.1% of females) students.

Involuntary sexual intercourse such as rape and sexual abuse may occur more commonly among adolescents, especially younger adolescent women, and often pose a potential risk for acquisition of STDs. A study on the effects of child abuse (i.e., incest, extra-familial sexual abuse, and physical abuse) on adolescent males showed a strong association between abuse and a number of risk-taking behaviors, such as forcing female sexual partners into having sexual intercourse and drinking alcohol prior to sexual intercourse. Moreover, when sexual intercourse is intermittent, as it is with most sexually experienced adolescents, the adolescents are less likely to take proper measures to safeguard against STDs.

CONTRACEPTIVE USE Sexually experienced adolescents are also at risk for STDs because of their patterns of contraceptive use, especially their use of barrier-method contraceptives. Some data indicate that adolescents do not use effective methods to reduce their risk of STDs or unintended pregnancies. Sexual abstinence is the only sure method of eliminating risk for STDs. When used consistently and correctly, however, condoms offer the best protection against acquisition of STDs, including HIV. Even when condoms are used improperly they reduce the risk of acquiring infections by 50 percent.

The overall reported use of contraceptives, particularly condoms, has increased among adolescents between 1994 and 2004. Data from the 2003 YRBSS reveal that 63.0 percent of the students who reported sexual activity in the three months prior to the survey also reported using condoms during their last sexual encounter; this behavior was more common among males of virtually all ages and racial/ethnic groups. In contrast, 20.6 percent of adolescent women ages 15 to 19 years reported use of birth control pills. It appears that while the use of oral contraceptives provides some protection against the development of gonococcal and nongonococcal forms of PID, it may increase the risk of chlamydial endocervical infections, and provides no protection against most STDs.

Differences in the types and patterns of contraceptive use by race/ethnicity, age, and socioeconomic status have also been noted. Also, adolescent women of higher income are more likely than young women of lower income to use oral contraceptives. These factors are related to access and use of medical services for reproductive health care. Thus, providing all sexually experienced adolescents with reproductive health counseling and education about the importance of consistently and correctly using barrier-method contraceptives such as condoms may play a crucial role in reducing their risk of acquiring and transmitting STDs.

ALCOHOL AND OTHER DRUG USE Use of alcohol and other drugs is prevalent among adolescents and thus poses a significant threat to their health. About 40 percent of high school youth responding to the YRBSS have used marijuana at least once with 22.4 percent of these students reporting use of this substance within 30 days before the survey. Cocaine was used at least once by 8.7 percent of the students and by 4.1 percent within 30 days of the survey. The substance of choice, however, is alcohol: 74.9 percent of students had at least one drink at some point in time and nearly half (44.9%) consumed alcohol in the 30 days prior to the survey. Among the current alcohol users, 28.3 percent had five or more drinks on at least one occasion, suggesting that a sizeable proportion of the students are periodic heavy drinkers. Grade, age, and gender differences were noted for lifetime and current use of alcohol and other illicit substances. In general, students in higher grade levels (grades 11 and 12) and males were more likely to use all substances. Racial/ethnic differences in use of substances were also found. Heavy use of alcohol was most prevalent among Caucasian and Hispanic males and females, while marijuana use was most common among African-American and Hispanic males.

Although these data strongly suggest that adolescents are at increased risk for social and physical morbidities, and even premature mortality because of their use of alcohol and other illicit substances, they underrepresent the actual prevalence of substance use among all adolescents. Teens who have dropped out or who are repeatedly absent from school and those who are homeless or otherwise disenfranchised are not represented by the reported data; many of these teens are potentially at higher risk for STDs because of their substance use behavior.

Substance use prior to sexual intercourse is likely to be related to a number of risk-taking behaviors: sexual intercourse with a casual acquaintance, lack of communication about use of condoms or previous sexual experiences, and no use of condoms. This association remained significant regardless of demographic factors, sexual experience, and dispositional factors such as adventure and thrill seeking. It appears that early intervention to prevent the use and abuse of alcohol and other substances may significantly decrease their risk of acquiring STDs.

Psychosocial factors

One study of college students examined the relationship between sexual behavior, substance use, and specific constructs from social cognitive theory (i.e., perceptions of self-efficacy, vulnerability to HIV risk, social norms, negative outcome expectancies of condoms, and knowledge of HIV risk and prevention). The results indicate that although young men expected more negative outcomes of condom use and were more likely to have sexual intercourse under the influence of alcohol and other drugs, young women reported perceptions of higher self-efficacy to practice safer sex. The study further revealed that perceptions of higher self-efficacy to engage in safer sexual behaviors, perceptions of fewer negative outcomes of condom use, and less frequent alcohol and drug use with sexual intercourse were the best predictors of safer sexual behaviors.

Evaluating STD risk

The information, motivation, and behavioral skills (IMB) model is one method of evaluating risk for STDs. This model posits that information, motivation, and behavior are the primary determinants of AIDS-related preventive behavior. Specifically, the model asserts that information regarding the transmission of HIV and information concerning specific methods of preventing HIV (e.g., condom use, decreasing the number of partners) are necessary prerequisites of reducing risk behaviors.

Motivation to change risk behaviors is another determinant of prevention and affects whether a person acts on his or her knowledge of the transmission and prevention of HIV. The IMB contends that motivation to engage in prevention behaviors is a function of one's attitudes toward the behavior and of subjective norms regarding prevention behaviors. Other critical factors which are hypothesized to influence motivation to engage in prevention behaviors are perceived vulnerability to acquiring HIV, perceived costs and benefits of engaging in prevention behaviors, intention to engage in prevention behaviors regarding HIV, as well as characteristics of the sex partner and/or the sexual relationship (e.g. primary vs. secondary partner).

Behavioral skills for engaging in specific prevention behaviors are a third determinant of prevention; it affects whether a knowledgeable, highly motivated person will be able to change his or her behavior to prevent HIV. Important skills required to engage in prevention behaviors include the ability to effectively communicate with one's sex partner about safer sex, refusal to engage in unsafe sexual practices, proper use of barrier-method contraceptives, and the ability to exit a situation when prevention behaviors are not possible. In addition, individuals who are able to practice prevention skills are presumed to have a strong belief in their ability to practice these prevention behavioral skills. Overall, the IMB asserts that information and motivation trigger behavioral skills to affect the initiation and maintenance of HIV prevention behaviors.

Symptoms of common STDs

The symptoms of some STDs may seriously affect an infected individual's quality of life or eventually become fatal, while others are so mild as to go undetected. The symptoms of some of the more prevalent STDs include:

  • Gonorrhea: The most common symptoms among infected adolescent girls are vaginal discharge, bleeding between menstrual cycles, and painful urination. Among adolescent boys, common symptoms are burning or painful urination and pus-like discharge from the penis. Many infections, however, remain asymptomatic in both females (32%) and males (2%). Symptoms are similar among young children who have contracted gonorrhea from a sexual abuser.
  • Chlamydia: Symptoms of chlamydia are similar to those of gonorrhea and sometimes difficult to differentiate clinically. Chlamydial infections are more likely to be asymptomatic than gonorrheal infections and thus are of longer duration on average.
  • Syphilis: In primarily syphilis, the characteristic symptom is the appearance of a chancre (painless ulcer) at the site of initial exposure (e.g. external genitalia, lips, tongue, nipples, or fingers). In some cases, the infected individual will experience swollen lymph glands. In secondary syphilis, the infection becomes systemic and the individual experiences symptoms such as fever , headache , sore throat , rash, and swollen glands. During latent syphilis, symptoms go unnoticed. During the late stage of syphilis, the infection has spread to organ systems and may cause blindness, signs of damage to the nervous system and heart, and skin lesions.
  • Herpes simplex virus: The symptoms of genital herpes include burning and itching of the genital area, blisters or sores on the genitals, discharge from the vagina or penis, and/or flu-like symptoms such as headache and fever.
  • Human papillomavirus (HPV): The warty growths of HPV can appear on the external or internal reproductive organs of males and females but are commonly found on the labia minora and the opening to the vagina in females and the penis in males. They may be small and few or combine to form larger growths.
  • Human immunodeficiency virus (HIV): Some persons who are newly infected with HIV have rash, fever, enlarged lymph nodes, and a flu-like illness sometimes called HIV seroconversion syndrome. This initial syndrome passes without intervention, and later symptoms, when T-cells become depleted, include weight loss, chronic cough , fever, fatigue, chronic diarrhea , swollen glands, white spots on the tongue and inside of the mouth, and dark blotches on the skin or in the mouth.

When to call the doctor

If a child or adolescent develops any of the symptoms of STDs, he or she should be evaluated for possible infection. Routine pelvic exams are recommended for all sexually active females and all females over the age of 18.


A history of sexual activity is collected from all individuals at increased risk of contracting an STD, including adolescents who admit to being sexually active or who are pregnant or have undergone therapeutic abortion, adolescents or children with symptoms indicative of infection with an STD, and adolescents or children suspected of being victims of sexual abuse or rape. The healthcare provider will take a complete medical history and perform a thorough physical examination. Depending on the STD in question, additional tests may be performed such as blood work, Papanicolaou (pap) smear, rectal swabs, or biopsy.


The treatment of sexually transmitted diseases varies according to the diagnosed infection. Gonorrhea, chlamydia, and syphilis are curable in most cases with antibiotics , although antibiotic-resistant strains do exist. As viruses, HSV, HPV, and HIV are treatable but not curable. The frequency and duration of HSV lesions can be reduced with antiviral therapy, including acyclovir (Zovirax), famciclovir (Famvir), and valacyclovir (Valtrex). Common methods to reduce genital warts include application of a topical cream called imiquimod (Aldara), cryotherapy (freezing of the wart), elecrosurgery (applying an electrical current to the wart), and surgical removal. The course of HIV infection can be slowed with a number of different kinds of drugs, including reverse transcriptase inhibitors, protease inhibitors, nonnucleoside reverse transcriptase inhibitors, and fusion inhibitors.

Alternative treatment

A number of different alternative therapies may be pursued to treat STDs, such as the use of herbs, homeopathy, acupuncture, and nutritional supplements, although minimal research has been done to establish their efficacy.

Nutritional concerns

In some cases, supplementation with specific nutrients may enhance immunity and minimize outbreaks. Examples are vitamin C (to boost the immune system), zinc (to reduce the frequency of HSV outbreaks), aloe (a possible antiviral), lemon balm (to speed healing), and licorice (with anti-inflammatory and antiviral effects).


Most STDs have excellent prognoses and respond well to treatment. While HSV and HPS are not curable, outbreaks can be managed and infection generally has little effect on quality of life. HIV, however, is a potentially fatal disease which can be treated but not cured.


The prevalence data on STDs, HIV, and AIDS in adolescents indicate that younger women, gay and bisexual teens, and poor, urban and racial/ethnic minority young people have higher rates of STDs and HIV relative to their peers. Primary prevention of initial STD infections through prevention and risk reduction programs are essential for stemming the tide of these sexually acquired diseases. Moreover, secondary prevention through screening at risk adolescents for asymptomatic STD infections and effectively treating the index case and his or her sexual contact(s) are the most effective means of eliminating long-term medical and psychosocial consequences from STDs.

Prevention of high risk sexual, contraceptive, and substance use behaviors through cognitive-behavioral skills training and prevention and risk reduction counseling programs is a key strategy for decreasing the high incidence of STDs in adolescents. Prevention and risk reduction strategies should be developed and implemented in settings in which most adolescents can be reached, including schools or community-based programs in which there are multiple opportunities to intervene with adolescents or clinical settings where one-to-one risk reduction counseling can occur and actual risk can be assessed.

Cognitive-behavioral skills building interventions

In order to prevent new STD infections, adolescents must not only be informed about the risk and prevention of STDs, they must also have skills to resist peer pressure , negotiate the use of condoms, and project the future consequences of their behaviors. In addition, prevention of STDs in adolescents requires that they have the necessary means, resources, and social support to develop self-regulative skills and self-efficacy to effectively reduce their risk of disease transmission. Such cognitive-behavioral skills building programs have been shown to be effective in developing skills, delaying the onset of sexual activity, and changing high risk behaviors associated with pregnancy, STDs, and HIV infection. Moreover, cognitive-behavioral skills building programs should be immediate, sustained, and cost-effective. Specifically, these programs should be designed to increase knowledge about the prevention and transmission of STDs and their consequences; formulate realistic attitudes and perceptions about personal susceptibility to acquiring infections; enhance self-efficacy and self-motivation; monitor and regulate STD-related risk behaviors; address the role of social peer norms; and develop appropriate decision-making, problem-solving, and communication skills .

Prevention and risk reduction counseling

Counseling strategies to prevent and reduce the risk of STDs should be conducted in a confidential and nonjudgmental manner that is both developmental and culturally appropriate for the adolescent. Counseling should focus on a number of key elements such as maintenance and support of healthy sexual behaviors (e.g. delaying initiation of sexual intercourse, limiting the number of sexual partners), use of barrier-method contraceptives (e.g. condoms, diaphragms, spermicide), routine medical care and advice (e.g. seeking medical care if the adolescent has participated in high-risk behavior), compliance with treatment recommendations (e.g. taking all medications as directed), and encouraging sex partners to seek medical care. Adolescents should also be informed about the myths and misconceptions of acquiring STDs. Moreover, adolescents should receive anticipatory guidance to assist them in defining appropriate options and alternatives to engaging in high-risk behaviors.

Parental concerns

Parents should be encouraged to talk to their children about sexually transmitted diseases and the risks of sexual activity. By asking preteens or teenagers questions about what they knows about STDs or by using cues from television shows or newspaper articles, parents can help make their children more comfortable talking about sex and the risks of infection, thereby opening the lines of communication. It is important that adolescents be provided accurate information, even if they already have some knowledge on the topic. Research has shown teens are not more likely to have sex if they are informed about safe sex practices, but they are more likely to practice safer sex.


Opportunistic infection —An infection that is normally mild in a healthy individual, but which takes advantage of an ill person's weakened immune system to move into the body, grow, spread, and cause serious illness.

Pap test —A screening test for precancerous and cancerous cells on the cervix. This simple test is done during a routine pelvic exam and involves scraping cells from the cervix. These cells are then stained and examined under a microscope. Also known as the Papanicolaou test.



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Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. Web site:


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Stephanie Dionne Sherk

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