National Overview of Sexually Transmitted Diseases (STDs), 2009

Organized collaboration among interested, committed public and private organizations and communities is the key to reducing sexually transmitted diseases (STDs) and their related health burdens. As noted in the Institute of Medicine report, 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 for 2009 on the three notifiable diseases for which there are federally funded control programs: chlamydia, gonorrhea, and syphilis. Several observations for 2009 are worthy of note.

Chlamydia

In 2009, a total of 1,244,180 cases of sexually transmitted Chlamydia trachomatis infection were reported to the Centers for Disease Control and Prevention (CDC) (Table 1). This is the largest number of cases ever reported to CDC for any condition. This case count corresponds to a rate of 409.2 cases per 100,000 population, an increase of 2.8% compared with the rate in 2008. 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 (PID) and related complications.

The continued increase in chlamydia case reports in 2009 most likely represents a continued increase in screening for this infection, expanded use of more sensitive tests, and more complete national reporting, but it also may reflect a true increase in morbidity.

In 2009, the overall rate of chlamydial infection in the United States among women (592.2 cases per 100,000 females) was almost three times the rate among men (219.3 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 chlamydial infection. During 2005–2009, the chlamydia rate in men increased 37.6%, compared with a 20.3% increase in women during this period. Rates also varied among different racial and ethnic minority populations. For example, in 2009, the chlamydia rate in black men was nearly 12 times higher than that in white men; the rate in black women was nearly 8 times higher than that in white women.

Data from multiple sources on the prevalence of chlamydial infection in defined populations have been useful in monitoring disease burden and guiding chlamydia screening programs.

In 2009, the median state-specific chlamydia test positivity was 7.5% (range: 3.5% to 15.5%) among women aged 15–24 years who were screened at selected family planning clinics in all 50 states, the District of Columbia, Puerto Rico, and the Virgin Islands (Figures 10 and 11).

At selected prenatal clinics in 18 states, Puerto Rico, and the Virgin Islands, the median state-specific chlamydia positivity was 7.7% (range: 3.6% to 20.4%) (Figure B).

The prevalence of infection was greater among economically disadvantaged women aged 16–24 years who entered the National Job Training Program (NJTP) in 2009 in 43 states, the District of Columbia, and Puerto Rico. The median state-specific prevalence was 11.3% (range: 4.2% to 19.0%) (Figure K). Among men entering the program in 2009 in 48 states, the District of Columbia, and Puerto Rico, the median state-specific chlamydia prevalence was 7.0% (range: 2.4% to 11.7%) (Figure L).

Among females entering juvenile corrections facilities, the median facility-specific chlamydia positivity was 14.4% (range: 1.8% to 35.7%). Among males entering juvenile corrections facilities, the median facility-specific chlamydia positivity was 6.0% (range: 0.0% to 19.4%).

Gonorrhea

Following a 74% decline in the rate of reported gonorrhea during 1975–1996, overall gonorrhea rates plateaued for 10 years and then decreased during the past 3 years. In 2009, a total of 301,174 cases of gonorrhea were reported in the United States, which corresponds to a rate of 99.1 cases per 100,000 population. The 2009 rate is a 10.5% decrease from the rate of 110.7 cases per 100,000 population in 2008 (Figure 14, Table 1).

In 2009, as in previous years, the South had the highest gonorrhea rate among the four regions of the country (Table 13). Rates in the South and Midwest remained higher than rates in the Northeast and West. Rates in all regions of the country have decreased for the last 2 years (Figure 16).

During 1996–2009, gonorrhea rates in men and women were similar, but slightly higher in women in more recent years (Figure 15). In 2009, the gonorrhea rate in women was 105.5 cases per 100,000 population compared with a rate of 90.8 in men (Figure 15). As with chlamydia, gonorrhea rates in women were highest among those aged 15–24 years. In men, they were highest among those aged 20–24 years (Figure 19). In 2009, the gonorrhea rate in black men was 26 times higher than that in white men; the rate in black women was 17 times higher than that in white women.

As with chlamydia, data on gonorrhea prevalence in defined populations were available from several sources in 2009. These data showed a continuing high burden of disease in some adolescents and young adults in parts of the United States.

In 2009, the median state-specific gonorrhea test positivity among women aged 15–24 years screened in selected family planning clinics in 46 states, the District of Columbia, Puerto Rico, and the Virgin Islands was 1.0% (range: 0.0% to 3.4%) (Figure 25). In 2009, the median state-specific gonorrhea test positivity among women aged 15–24 years screened in selected prenatal clinics in 18 states, Puerto Rico, and the Virgin Islands was 1.2% (range: 0.0% to 5.5%) (Figure D).

For women aged 16–24 years entering the NJTP in 41 states, the District of Columbia, and Puerto Rico in 2009, the median state-specific gonorrhea prevalence was 1.6% (range: 0.0% to 5.0%) (Figure M). Among men entering the program in 33 states, the District of Columbia, and Puerto Rico, the median state-specific gonorrhea prevalence was 0.6% (range: 0.0% to 3.4%) (Figure N).

Among females entering juvenile corrections facilities, the median facility-specific gonorrhea positivity was 2.9% (range: 0.0% to 13.4%); the median facility-specific gonorrhea positivity for males entering juvenile corrections facilities was 0.7% (range: 0.0% to 6.5%).

Syphilis

The rate of primary and secondary (P&S) syphilis reported in the United States decreased during the 1990s, and in 2000, it was the lowest since reporting began in 1941. The low rate of syphilis and the concentration of most 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 1999 and updated in 2006.² The overall rate of P&S syphilis in the United States declined 89.7% during 1990–2000, but has increased each year since 2001, mostly in men, but also in women during 2004–2008. The overall rate in women declined slightly in 2009.

In 2009, a total of 13,997 cases of P&S syphilis were reported to CDC. This case count is the highest number of cases reported since 1995 and corresponds to a rate of 4.6 cases per 100,000 population, a 5% increase from 2008. Since 2005, the rate of P&S syphilis has increased 59%.

After 14 years of decline, the number of reported cases of congenital syphilis reached a historic low of 339 cases in 2005. The number of cases has since increased, with 427 cases reported in 2009, a 26% increase since 2005.

Although wide disparities exist in the rates of STDs among racial and ethnic groups, these disparities have decreased for syphilis over the past 10 years. In 2009, the P&S syphilis rate among blacks was 9 times the rate among whites (Table 34B), which is substantially lower than the disparity observed in 1999, when the rate among blacks was 24 times higher than the rate among whites.

However, during 2005–2009, syphilis rates increased 167% among black men aged 15–19 years (Table 34B) and 212% among those aged 20–24 years. This increase is the largest observed in any age, sex, or racial/ethnic group. The 2009 rate among men aged 15–19 years was 26 times higher for blacks than for whites. Among black women aged 15–24 years, rates doubled during 2005–2009. In 2009, rates were 29 times higher for black women aged 15–19 years than for white women of the same age.

Although efforts to eliminate syphilis have focused on racial and ethnic minority populations, the syphilis rates among all men who have sex with men (MSM) have increased since 2001. Rates also have increased recently among black women and among black men who have sex with women (MSW). These findings highlight the importance of continually reassessing and refining surveillance, prevention, and control strategies to eliminate syphilis.

1 Eng TR, Butler WT, editors; Institute of Medicine (US). The hidden epidemic: confronting sexually transmitted diseases. Washington (DC): National Academy Press; 1997. p.43.

2 Centers for Disease Control and Prevention. The national plan to eliminate syphilis from the United States. Atlanta: U.S. Department of Health and Human Services; 2006.