National Overview of Sexually Transmitted Diseases, 2002

     The logo on the cover of Sexually Transmitted Disease Surveillance, 2002 is a reminder of the multifaceted, national dimensions of the morbidity, mortality, and costs that result from sexually transmitted diseases (STDs) in the United States. It highlights the central role of STD prevention in improving health among women and infants and in promoting HIV prevention. Organized collaboration among interested, committed public and private organizations is the key to reducing STDs and their related health burdens in our population. As noted in the report of the Institute of Medicine, The Hidden Epidemic: Confronting Sexually Transmitted Diseases,¹ surveillance is a key component of our efforts to prevent and control these diseases.

     This overview summarizes national surveillance data on the three diseases for which there are federally-funded control programs: chlamydia, gonorrhea, and syphilis. Several observations for 2002 are worthy of note.

Chlamydia

     In 2002, 834,555 cases of genital Chlamydia trachomatis infection were reported to CDC (Table 1). This case count corresponds to a rate of 296.5 cases per 100,000 population, an increase of 6.5% compared with the rate of 278.3 in 2001. Rates of reported chlamydial infections among women have been increasing annually since the late 1980s when public programs for screening and treatment of women were first established to avert pelvic inflammatory disease and related complications. Chlamydia screening and reporting are likely to expand further in response to the recently implemented Health Plan Employer Data and Information Set (HEDIS) measure for chlamydia screening of sexually active women 15 to 25 years of age who are provided medical care through managed care organizations.² The increase in chlamydia case reports in 2002 most likely represents a continued increase in screening for this infection and also increased use of more sensitive chlamydia screening tests than used in prior years.

     In 2002, the overall rate of chlamydial infection in the U.S. among women (455.4 cases per 100,000 females) was over three times the rate among men (130.1 cases per 100,000 males), reflecting the large number of women screened for this disease (Tables 5 and 6). However, with the increased availability of urine testing, men are increasingly being tested for chlamydial infection. From 1998 to 2002, the reported chlamydial infection rate in men increased by 54.7% (from 84.1 to 130.1 cases per 100,000 males) compared with a 19.6% increase in women over this period (from 380.8 to 455.4 cases per 100,000 females).

     Data from multiple sources on prevalence of chlamydial infection in defined populations have been useful in monitoring disease burden and guiding chlamydia screening programs. In 2002, the median state-specific chlamydia test positivity among women 15 to 24 years who were screened at selected family planning clinics in all states, the District of Columbia, Puerto Rico, and the Virgin Islands was 5.6% (range 3.0% to 14.2%) (Figure 8), and at selected prenatal clinics in 26 states and the Virgin Islands was 7.4% (range 1.5% to 14.4%) (Figure F). For economically-disadvantaged women 16 to 24 years of age who entered the National Job Training Program in 2002, from 28 states and Puerto Rico, the median state-specific prevalence was 10.1% (range 4.4% to 16.8%) (Figure L). For women 15 to 30 years of age screened at Indian Health Service (IHS) clinics in 3 IHS areas, the prevalence ranged from 7.4% to 9.7% by area (Figure U). For adolescent women entering juvenile detention centers, the median chlamydia positivity by facility was 16.7% (range 6.3% to 28.3%) (Figure II). It was 13.2% among women attending school-based clinics and 9.7% in female street youth (Figure M). For adolescent men entering juvenile detention centers, the median chlamydia positivity was 6.0% by facility (range 0.6% to 15.7%) (Figure JJ). Although these data on prevalence are not entirely comparable because of differences in the populations screened, in the performance characteristics of the screening tests, and variations in screening criteria, they provide important information on the continuing high burden of disease in the United States.

     In parts of the United States where large scale chlamydia screening programs have been instituted, prevalence of infection has declined. During 1988-2002, among 15-to 44-year-old women participating in the screening programs in Health and Human Services (HHS) Region X family planning clinics, chlamydia test positivity declined 55.4% (from 13.0% to 5.8%) (Figure 9). After adjusting trends in chlamydia positivity to account for changes in laboratory test methods and associated increases in test sensitivity, chlamydia test positivity decreased in 6 of 10 HHS regions from 2001 to 2002 and increased in 4 regions. Although chlamydia positivity has declined in the past year in some regions, most likely due to the effectiveness of screening and treating women, continued expansion of screening programs to populations with higher prevalence of disease may have contributed to the increases in positivity seen in other regions. See the Appendix (Sources and Limitations of Data) for the composition of the HHS regions.

Gonorrhea

     Following a 73.8% decline in the rate of reported gonorrhea from 1975 (467.7 cases per 100,000 population) to 1997 (122.4 cases per 100,000 population), overall rates increased in 1998 (131.9 per 100,000 population) and have been declining slightly since 1999 (Table 1). The gonorrhea rate for 2002 (125.0 cases per 100,000 population) was slightly lower than rates in 2001 (128.5 cases per 100,000 population) and 2000 (129.0 per 100,000 population) (Table 1). The 2002 rate for gonorrhea considerably exceeds the Healthy People 2010 (HP2010) objective of 19 cases per 100,000 population.

     The gonorrhea rate in the U.S. among women in 2002 was slightly lower than the rate in 2001 (125.3 and 128.2 cases per 100,000 women, respectively) (Table 15). As in 2001, there were minimal differences between sexes in gonorrhea rates in 2002 (Tables 15 and 16). Since 1998, the rate of gonorrhea among 15- to 19-year-olds has decreased by 12.2%. As with chlamydia, rates of gonorrhea in women are particularly high in 15- to 19-year-olds, and in men, are highest in the 20- to 24-year age group (Table 21).

     In 2002, data on gonorrhea prevalence in defined populations were available from several sources. These data showed a continuing high burden of disease in adolescents and young adults in some parts of the United States. Among 15- to 24-year-old women attending selected family planning clinics in 35 states, the District of Columbia, Puerto Rico, and the Virgin Islands, the median state-specific gonorrhea prevalence was 0.9% (range 0.1% to 2.8%) (Figure 17). For women in this age group attending selected prenatal clinics in 20 states and the Virgin Islands, the median prevalence was 0.9% (range 0.0% to 5.7%) (Figure G). However, for 16- to 24-year-old women entering the National Job Training Program in 21 states in 2002, the median state-specific gonorrhea prevalence was 2.9% (range 0.0% to 6.8%) (Figure O).

     Antimicrobial resistance in Neisseria gonorrhoeae remains a continuing concern. In the mid- to late 1990s, the prevalence of fluoroquinolone-resistant N. gonorrhoeae infections increased substantially in Asia and the Pacific Islands, including Hawaii; in 2002, increased numbers of fluoroquinolone-resistant N. gonorrhoeae infections were identified in California. Nationally in 2002, 2.2% of N. gonorrhoeae isolates tested through the Gonoccocal Isolate Surveillance Project (GISP) demonstrated resistance to ciprofloxacin, compared to 0.7% in 2001 and 0.4% in 2000. There is considerable geographic variation in the prevalence of fluoroquinolone-resistance within the U.S. Outside of Hawaii and California, 0.4% demonstrated resistance. In Honolulu, the proportion of GISP isolates that were resistant to ciprofloxacin remained high in 2002 at 11.7%, although this was lower than in the previous two years (20.3% in 2001 and 14.3% in 2000). Also, in 2002, increased numbers of GISP isolates resistant to ciprofloxacin were identified in all four California GISP sites (7.2% in Long Beach, 11.4% in Orange County, 16.5% in San Diego, and 6.7% in San Francisco). As a result of these data, the 2002 CDC STD Treatment Guidelines³ recommend that fluoroquinolones not be used for treatment of gonorrhea acquired in Asia, the Pacific Islands, including Hawaii, or in other areas with high levels of resistance such as California. See Appendix for a further description of GISP.

     Data on characteristics of patients in the GISP sample have been used to describe trends in the sexual orientation of male STD clinic patients with gonorrhea. In 2002, there was a marked increase in the proportion of GISP isolates from men who have sex with men (MSM), with 21.0% of isolates from MSM compared with 17.2% in 2001 and 13.9% in 2000 (Figure EE). In 1988, only 4.0% of isolates were from MSM. The proportional increase in MSM in GISP has corresponded to an absolute increase in gonorrhea cases among MSM at STD clinics in several large cities that participate in GISP.

Syphilis

     The rate of primary and secondary (P&S) syphilis reported in the United States decreased during the 1990s and in 2000 was the lowest since reporting began in 1941. The low rate of syphilis and the concentration of the majority of syphilis cases in a small number of geographic areas led to the development of the National Plan to Eliminate Syphilis from the United States, which was announced by the Surgeon General in October 1999.⁴ The rate of P&S syphilis in the United States declined by 89.2% from 1990 through 2000. However, the rate of P&S syphilis increased slightly in 2001 and more substantially in 2002; these increases were observed only in men.

     Despite continued national progress toward syphilis elimination among women and African-Americans, syphilis remains an important problem in the South and, increasingly, in some urban areas with large populations of MSM. Recently, outbreaks of syphilis among MSM have been reported, possibly reflecting increases in risky behavior in this population.

     P&S syphilis cases reported to CDC increased 12.4% from 6,103 in 2001 to 6,862 in 2002. The overall rate of P&S syphilis in the United States in 2002 (2.4 cases per 100,000 population) was slightly above the rate reported in 2001 (2.2 cases per 100,000), and was considerably higher than the Healthy People 2010 (HP2010) objective of 0.2 case per 100,000 population (Figure 23, Table 1). The rate of P&S syphilis among women decreased from 1.4 cases per 100,000 population in 2001 to 1.1 cases per 100,000 population in 2002; among men, the rate increased from 3.0 to 3.8 cases per 100,000 population (Tables 28 and 29).

     One factor that may facilitate syphilis elimination efforts is that this disease continues to be primarily reported only in specific areas of the country. In 2002, 2,534 (80.7%) of the 3,139 counties in the United States reported no cases of P&S syphilis (see Appendix for details on county coding). Half of all the P&S syphilis cases were reported from only 16 counties and 1 city (0.5% of total number of U.S. counties) (Table 26). However, the 2002 P&S syphilis rates were greater than the HP2010 objective in 595 counties (19.0% of the total number of U.S. counties). These 595 counties accounted for more than 99.9% of all reported P&S syphilis cases.

     Between 2001 and 2002, the national rate of congenital syphilis decreased by 16.4%, from 12.2 to 10.2 cases per 100,000 live births (Table 42). The continuing reduction in congenital syphilis rates, occurring since the early 1990s, reflects the substantial and continuing reduction in the rate of P&S syphilis among women over the same period. In 2002, approximately one half of the states and outlying areas had a rate of congenital syphilis that was greater than the HP2010 objective of 1.0 case per 100,000 live births (Table 41).

     Although wide disparities exist in the rates of STDs among racial and ethnic groups, there has been a reduction in these differences for syphilis over the past five years. The P&S syphilis rate for 2002 among African-Americans was 8 times the rate among whites, reflecting a substantial decline from 1998, when the rate among African-Americans was 34 times greater than that among whites (Table 35B). While this reflects decreasing rates among African-Americans, in the past two years, it also reflects significant increases among whites.

     While syphilis elimination efforts have successfully focused on heterosexual minority populations at risk for syphilis, recent increases in syphilis among MSM highlight the importance of continually reassessing and refining surveillance, prevention, and control strategies.

¹ Institute of Medicine. The Hidden Epidemic: Confronting Sexually Transmitted Diseases, Committee on Prevention and Control of Sexually Transmitted Diseases, National Academy Press, Washington, DC, 1997.

² National Committee for Quality Assurance (NCQA). HEDIS 2000: Technical Specifications, Washington, DC, 1999, pp. 68-70, 285-286.

³ Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines 2002. MMWR 2002;51 (No. RR-6).

⁴ Division of STD Prevention. The National Plan to Eliminate Syphilis from the United States. National Center for HIV, STD, and TB Prevention, Centers for Disease Control and Prevention, 1999.