The logo on the cover of Sexually Transmitted Disease Surveillance, 2003 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 2003 are worthy of note.

Chlamydia

In 2003, 877,478 cases of genital Chlamydia trachomatis infection were reported to CDC (Table 1). This case count corresponds to a rate of 304.3 cases per 100,000 population, an increase of 5.1% compared with the rate of 289.4 in 2002. Rates of reported chlamydia 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 2003 most likely represents a continued increase in screening for this infection and also increased use of more sensitive chlamydia screening tests than in prior years.

In 2003, the overall rate of chlamydia infection in the United States among women (466.9 cases per 100,000 females) was over three times the rate among men (134.3 cases per 100,000 males), reflecting the large number of women screened for this disease (Tables 4 and 5). However, with the increased availability of urine testing, men are increasingly being tested for chlamydia infection. From 1999 through 2003, the chlamydia rate in men increased by 46.6% (from 91.6 to 134.3 cases per 100,000 males) compared with an 18.2% increase in women over this period (from 395.1 to 466.9 cases per 100,000 females).

Data from multiple sources on prevalence of chlamydia infection in defined populations have been useful in monitoring disease burden and guiding chlamydia screening programs. In 2003, 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 5.9% (range 2.8% to 18.9%) (Figure 8), and at selected prenatal clinics in 27 states, Puerto Rico, and the Virgin Islands was 7.4% (range 2.4% to 19.7%) (Figure F). For economically-disadvantaged women 16 to 24 years of age who entered the National Job Training Program in 2003, from 39 states and Puerto Rico, the median state-specific prevalence was 9.9% (range 3.4% to 16.0%) (Figure M). Among men entering the program from 38 states and Puerto Rico from July through December 2003, the median state-specific chlamydia prevalence was 7.8% (range 1.5% to 12.7%) (Figure N). Among women 15 to 30 years of age screened at Indian Health Service (IHS) clinics in two IHS areas, the chlamydia prevalence was 11.0% (Figure X). For adolescent women entering 48 juvenile detention centers, the median chlamydia positivity by facility was 15.9% (range 2.7% to 33.5%) (Figure JJ). It was 11.3% among women attending school-based clinics (Figure O). Among adolescent men entering 64 juvenile detention centers, the median chlamydia positivity was 5.4% by facility (range 1.3% to 12.9%) (Figure KK). 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.

During 1988-2003, among 15- to 24-year-old women participating in the screening programs in Health and Human Services (HHS) Region X family planning clinics, chlamydia test positivity declined 52.3% (from 15.1% to 7.2%) (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 4 of 10 HHS regions from 2002 through 2003, increased in 5 regions, and remained the same in 1 region. 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

In 2003, 335,104 cases of gonorrhea were reported in the United States. Following a 74.3% decline in the rate of reported gonorrhea from 1975 (467.7 cases per 100,000 population) to 1997 (120.2 cases per 100,000 population), overall rates increased slightly in 1998 (129.2 per 100,000 population). Since 1999, the gonorrhea rate has decreased 10.1% to the current rate of 116.2 per 100,000 population (Table 1). Although this is the lowest gonorrhea rate the United States has ever reported, the 2003 rate for gonorrhea considerably exceeds the Healthy People 2010 (HP2010) target of 19 cases per 100,000 population.

As in the past 7 years, there were minimal differences between sexes in gonorrhea rates in 2003 (Figure 15). Since 1999, the rate of gonorrhea among 15- to 19-year-olds has decreased by 14.7%. 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 (Figure 17 and Table 20). Similar to previous years, in 2003, African-American 15- to 19-year-old females had the highest gonorrhea rate of any age and race/ethnic group (2,947.8 cases per 100,000 population) (Table 21B). However, gonorrhea rates among African-Americans of both sexes and all age groups decreased in 2003.

In 2003, 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 39 states, the District of Columbia, Puerto Rico, and the Virgin Islands, the median state-specific gonorrhea positivity was 0.8% (range 0.1% to 4.0%) (Figure 18). For women in this age group attending selected prenatal clinics in 23 states, Puerto Rico, and the Virgin Islands, the median positivity was 1.0% (range 0.0% to 3.7%) (Figure G). However, for 16- to 24-year-old women entering the National Job Training Program in 34 states and Puerto Rico in 2003, the median state-specific gonorrhea prevalence was 2.1% (range 0.0% to 6.3%) in 2003 (Figure Q). Among men entering the program from 10 states from July through December 2003, the median state-specific gonorrhea prevalence was 2.8% (range 1.4% to 6.3%) (Figure R).

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 2003, 4.1% of N. gonorrhoeae isolates tested through the Gonoccocal Isolate Surveillance Project (GISP) demonstrated resistance to ciprofloxacin (a fluoroquinolone), compared to 2.2% in 2002 and 0.7% in 2001. There is considerable geographic variation in the prevalence of fluoroquinolone-resistance within the United States. Outside of Hawaii and California, 1.2% of N. gonorrhoeae isolates demonstrated resistance. In Honolulu, the proportion of GISP isolates that were resistant to ciprofloxacin remained high in 2003 at 13.3%. Also, in 2003, the proportion of GISP isolates that were resistant to ciprofloxacin remained high in California: (19.4% in Long Beach, 31.5% in Orange County, 13.2% in San Diego, 19.2% in San Francisco, and 12.4% in Los Angeles). 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. The proportion of GISP isolates among men who have sex with men (MSM) that were resistant to ciprofloxacin more than doubled from 7.2% in 2002 to 15% in 2003. The proportion among heterosexuals increased from 0.9% in 2002 to 1.5% in 2003. In 2004 CDC recommended that fluoroquinolones no longer be used to treat gonorrhea among MSM.⁴ 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 2003, there was little change in the proportion of GISP isolates from MSM, with 19.6% of isolates from MSM compared with 20.7% in 2002 and 17.2% in 2001 (Figure HH). In 1988, only 4.0% of isolates were from MSM.

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 1999.⁵ 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 has increased each year since 2001. Overall, increases have occurred only among 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 from 6,862 cases in 2002 to 7,177 in 2003. The overall rate of P&S syphilis in the United States in 2003 (2.5 cases per 100,000 population) was slightly higher than the rate in 2002 (2.4 cases per 100,000), and was considerably higher than the Healthy People 2010 (HP2010) target of 0.2 case per 100,000 population (Figure 25, Table 1). The rate of P&S syphilis among women decreased from 1.1 cases per 100,000 population in 2002 to 0.8 cases per 100,000 population in 2003; among men, the rate increased from 3.7 to 4.2 cases per 100,000 population (Figure 29 and Table 33).

One factor that may facilitate syphilis elimination efforts is that this disease continues to be primarily reported from a limited number of counties in the country. In 2003, 2,530 (80.6%) of the 3,140 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 18 counties and 1 city (0.6% of total number of U.S. counties) (Table 25). However, 2003 P&S syphilis rates were greater than the HP2010 target in 602 counties (19.2% of the total number of U.S. counties). These 602 counties accounted for 99.9% of all reported P&S syphilis cases in 2003.

Between 2002 and 2003, the national rate of congenital syphilis decreased by 8.8%, from 11.3 to 10.3 cases per 100,000 live births (Table 39). The continued decrease in congenital syphilis rates, which has occurred since the early 1990s, reflects the substantial and continuing reduction in the rate of P&S syphilis among women during the same period. In 2003, 30 states and 2 outlying areas had a rate of congenital syphilis that was greater than the HP2010 target of 1.0 case per 100,000 live births (Tables 40 and 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 2003 among African-Americans was 5 times the rate among whites, reflecting a substantial decline from 1999, when the rate among African-Americans was 29 times greater than that among whites (Table 34B). While this reflects decreasing rates among African-Americans, it also reflects significant increases among whites during the past 3 years.

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 Centers for Disease Control and Prevention. Increases in fluoroquinolone-resistant Neisseria gonorrhoeae among men who have sex with men – United States, 2003, and revised recommendations for gonorrhea treatment, 2004. MMWR 2004;53:335-338.

⁵ 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.