Sexually Transmitted Infections in the United States

Of the top ten most frequently reported diseases in the United States in 1995, half--accounting for 87 percent of all cases--were sexually transmitted infections (STIs). With approximately 12 million new cases occurring annually, rates of curable STIs in the United States are the highest in the developed world. 1

The public and private costs of STIs are tremendous. A conservative estimate of total costs associated with the most common types is approximately $10 billion. This increases to $17 billion when HIV/AIDS infections are included. 2

Despite these tremendous health and economic burdens, the scope and impact of the STD epidemic are still underappreciated. And, to a large extent, the diseases are largely hidden from public discourse. 3

Incidence and Prevalence

• At least 1 person in 4 will contract an STI at some point in his or her life.
• More than 12 million Americans, 3 million of whom are teenagers, are infected with an STI each year.
• As many as 56 million American adults and adolescents may have an incurable viral STI other than HIV.
• Chlamydial infection is the most common bacterial STI. More than 4 million cases occur each year. Just 23 percent of American adults under 65 cite chlamydia when asked to name any STIs.
• About 200,000 to 500,000 new cases of genital herpes occur each year, and 31 million Americans are already infected with the genital herpes virus (herpes simplex virus, or HSV).
• At least 24 million people are infected with human papillomavirus (HPV) or genital warts, and as many as 1 million new infections occur each year. HPV is associated with cervical and other genital and anal cancers.
• Trends in viral STIs are unknown, but initial visits to doctors for genital warts and herpes have increased steadily over the last 30 years, dropping off slightly in the last five years.
• Between 1987 and 1991, the number of annually reported cases of syphilis--over 100,000--was at its highest levels in 40 years.
• At least 800,000 cases of gonorrhea occur each year.

Health Consequences

• Millions of women, men and children are affected by long-term complications of STIs, including various cancers, infertility, ectopic pregnancy and spontaneous abortion, and other chronic diseases.
• At least 15 percent of all infertile American women are infertile because of tubal damage caused by pelvic inflammatory disease (PID) resulting from an STI.
• Viral STIs result in lifelong incurable infection. Seventeen percent of
• American adults under 65 think all STIs are curable--but a large majority (80 percent) know that not all STIs are curable.
• STIs increase susceptibility to HIV. People with an active syphilis, genital herpes, or chancroid infection, or who have chlamydia, gonorrhea, or trichomoniasis are 3 to 5 times more likely to contract HIV than other people. More than half (54 percent) of American adults under 65 do not know that STDs increase susceptibility to HIV.

Impact on Women

• Complications of STIs are more severe and more frequent among women than among men. For example, women are more susceptible to reproductive cancers and infertility once infected.
• Women are biologically more susceptible than men to becoming infected if exposed to an STI. For example, a woman's risk of contracting gonorrhea from one act of unprotected intercourse is as high as 90 percent while the risk to a man is approximately 30 percent.
• Among couples with one infected partner, the annual risk of herpes infection is 19 percent when transmitted from a man to a woman and 5 percent when transmitted from a woman to a man.
• STIs are less likely to produce symptoms in women and are therefore more difficult to diagnose until serious problems develop. Up to 80 percent of chlamydia infections in women are asymptomatic compared to 40 percent in men. From 30 to 80 percent of women with gonorrhea are asymptomatic while fewer than 5 percent of men are asymptomatic.

Impact on Teenagers and Young Adults

• Three million teenagers--about 1 in 4 sexually experienced teenagers--acquire an STI every year. By the end of 1995, there were more than 2,300 teenagers diagnosed with AIDS.
• Young adults are the age groups at greatest risk of acquiring an STI for a number of reasons: they are more likely to have multiple sexual partners; they may be more likely to engage in unprotected intercourse; and their partners may be at higher risk of being infected.
• Compared to older adult women, female teenagers are more susceptible to cervical infections, such as gonorrhea and chlamydial infections, due to their cervical anatomy.
• Chlamydia is more common among teenagers than among adult men and women; in some studies, up to 30 percent of sexually active teenage women and 10 percent of sexually active teenage men tested for STIs were infected with chlamydia.

Critical Components of STD Prevention & Control

Communities need critical prevention and control services to help reduce costly complications of STDs. They should include both these patient-based and population-based approaches:

1. Screening high-risk populations for prevalent STIs.

   Because the prevalence of STIs varies from place to place, private sector providers may benefit from consulting with public health professionals on disease prevalence in their community in order to select cost-effective strategies for providing relevant STI screening services.

2. Treating individuals with diagnosed and presumptive infections.

   Recommendations of STI experts on treatment regimens for STIs should be readily available to health care providers. Quality assurance programs should be implemented to ensure that

3. Providing prevention counseling and education.

   Both public and private sources are needed to provide STI prevention counseling and education to individual patients in order to reach those affected by STIs. Such services are essential to reach sexual partners, to address future infections, as well as to ensure that medication is taken properly and that patients return for follow-up care. Community education about STI prevention is also important for beginning to change risky behavior before infection occurs,

4. Notifying, treating, and educating partners of persons diagnosed with STIs.

   A sexual partner who has been exposed to an STI should be informed of his or her potential infection by the infected person, his or her health care provider, the provider's staff, or public health staff trained in partner notification. In most states, the law protects public health personnel in the notification process but does not protect other persons. Private providers and public health personnel may work together to provide sexual contacts with information on all aspects of needed care. Notification is a key step to prevent reinfection and further spread of STIs.

5. Reporting STI cases to assist in planning, evaluating, resource allocating, and coordinating efforts.

   Health departments monitor and analyze reported STIs to identify problems in specific communities, to evaluate the effects of control measures, and to detect changes in trends. Complete and accurate reporting is essential so that the partnership of private providers and public health personnel can appropriately address STI problems. Laws in every state require providers to report some STIs. Most states require reporting of gonorrhea, syphilis, chlamydia, and AIDS. Several require reporting of herpes, HIV infection, or STI complications such as PID. Under-reporting of STIs results in failure to note disease trends and inadequate planning to address STI problems.

These approaches are needed because:

1. Screening and treatment will prevent significant future complications.

   When left untreated, STIs can result in severe consequences including infertility, tubal pregnancy, chronic pain, cancer, premature births, low birth weight, congenital infections in newborns, and even death. In addition, HIV transmission is much more likely when other STIs are present, making STI treatment an important intervention for prevention of HIV infection. For example:

   In the United States, chlamydia--which infects approximately 4 million people each year--causes the majority of uterine and fallopian tube infections or PID in women. PID is the leading cause of preventable infertility and tubal pregnancy. Tubal pregnancy, in turn, is the leading cause of first-trimester pregnancy-related death in African-American women. Prospective epidemiological studies have repeatedly demonstrated twofold to fivefold increases of HIV transmission when other STIs are present.

   In addition, other STIs have been demonstrated to increase HIV susceptibility in women by increasing the cells targeted by HIV CD4 cells in their cervical secretions. Other STIs have also been shown to increase the probability that HIV will be transmitted from an HIV-infected person to another person. A recent study demonstrated that in communities with improved STI treatment, HIV transmission was reduced by 42 percent.

2. Screening and early treatment are cost-effective.

   The cost of untreated STIs far exceeds the cost of prevention services. For example, evidence indicates that chlamydia screening and treatment decreases the incidence of costly complications, such as PID. A random trial of chlamydia screening demonstrated a 60 percent reduction in the incidence of PID in the screened group in the 12 months following testing. Treatment of the consequences of chlamydia (e.g., PID, infertility, ectopic pregnancy) is estimated to be 12 times greater than the cost of screening and treatment.

3. These approaches would result in a healthier population.

   STIs are strongly linked to long-term health complications. For example, the association between human papillomavirus and cervical cancer is well documented. STIs are one of the most important preventable causes of adverse outcomes of pregnancy, including low birth weight/prematurity, congenital infection, stillbirth, and postpartum infection. The two leading causes of preventable infertility are chlamydia and gonorrhea. Women, adolescents, and people of color are disproportionately affected by STIs and their consequences. STI prevention services could dramatically lower the incidence of STIs, their long-term consequences, and their significant cost. The overall health of Americans would improve with the routine availability of these components of STI prevention.

References and Additional Information

1. The Hidden Epidemic: Confronting Sexually Transmitted Diseases, National Academy Press, Washington, DC, December 1996.
2. Ibid.
3. Ibid.
4. The statistics in this Fact Sheet are from a briefing paper, Sexually Transmitted Diseases in the United States: Exposing the Epidemic, prepared by the Kaiser Family Foundation, The Alan Guttmacher Institute, and the National Press Foundation and based on: The Hidden Epidemic: Confronting Sexually Transmitted Diseases, The Institute of Medicine, National Academy Press, 1996.
5. Survey on Public Knowledge and Attitudes About STDs Other Than AIDS, Kaiser Family Foundation, 1996.
6. Testing Positive: Sexually Transmitted Disease and the Public Health Response, The Alan Guttmacher Institute, 1993.

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