National Overview of Sexually Transmitted Diseases (STDs), 2015
In 2015, a total of 1,526,658 cases of Chlamydia trachomatis infection were reported to the CDC. This case count corresponds to a rate of 478.8 cases per 100,000 population, an increase of 5.9% compared with the rate in 2014. During 2014–2015, the rate of reported chlamydia cases among women increased 3.8% and the rate among men increased 10.5%. Following three years of decreases in rates during 2011–2014, the rate among women aged 15–19 years increased 1.5% during 2014–2015.
In 2015, the overall rate of chlamydial infection in the United States among women (645.5 cases per 100,000 females) based on reported cases was over two times the rate among men (305.2 cases per 100,000 males), reflecting the larger number of women screened for this infection. However, with the increased availability of urine testing and extragenital testing, men, including gay, bisexual, and other men who have sex with men (collectively referred to as MSM) are increasingly being tested for chlamydial infection. During 2011–2015, the chlamydia rate in men increased 20.0%, compared with a 0.3% increase in women during this period.
The facilities reporting chlamydial infections have changed over the last 10 years. In 2015, over 75% of chlamydia cases were reported from venues outside of STD clinics. Among women, only 4.5% of chlamydia cases were reported through an STD clinic and about a third of cases were reported from private physicians/health maintenance organizations.
Rates of reported chlamydia varied among different racial and ethnic minority populations. In 2015, the rate of chlamydia among Blacks was 5.9 times the rate among Whites, and the rate among American Indians/Alaska Natives was 3.8 times the rate among Whites.
In 2009, the national rate of reported gonorrhea cases reached an historic low of 98.1 cases per 100,000 population. However, during 2009–2012, the rate increased slightly each year to 106.7 cases per 100,000 population in 2012 and then increased again during 2013–2015. In 2015, 395,216 gonorrhea cases were reported for a rate of 123.9 cases per 100,000 population, an increase of 12.8% from 2014.
During 2014–2015 the rate of reported gonorrhea increased 18.3% among men and 6.8% among women. Gonorrhea rates among both men and women increased in every region of the United States, with largest increases in the West and the South. The magnitude of the increase among males suggest either increased transmission or increased case ascertainment (e.g., through increased extra-genital screening) among MSM or both.
In 2015, the rate of reported gonorrhea cases remained highest among Blacks (424.9 cases per 100,000 population) and among American Indians/Alaska Natives (192.8 cases per 100,000 population). While rates of gonorrhea declined 4.0% among Blacks during 2011–2015, rates increased among all other racial and ethnic groups, including a 71.3% increase among American Indians/Alaska Natives.
Antimicrobial resistance remains an important consideration in the treatment of gonorrhea. With increased resistance to the fluoroquinolones and declining susceptibility to cefixime, dual therapy with ceftriaxone and azithromycin is now the only CDC recommended treatment for gonorrhea.2 In 2015, the percentage of isolates with elevated minimum inhibitory concentrations (MICs) of cefixime and ceftriaxone remained low (0.5% and 0.3%, respectively). During 2013–2015, the percentage of isolates with reduced azithromycin susceptibility increased from 0.6% to 2.6%. Continued monitoring of susceptibility patterns to these antibiotics is critical.
In 2000 and 2001, the national rate of reported primary and secondary (P&S) syphilis cases was 2.1 cases per 100,000 population, the lowest rate since reporting began in 1941. However, the P&S syphilis rate has increased almost every year since 2001. In 2015, a total of 23,872 P&S syphilis cases were reported, and the national P&S syphilis rate increased to 7.5 cases per 100,000 population, a 19.0% increase from 2014.
During 2014–2015, the P&S syphilis rate increased both among men (18.1%) and women (27.3%) and rates increased among both sexes in every region of the country. Nationally, P&S syphilis rates increased in every 5-year age group among those aged 15–64 years and in every racial and ethnic group except for American Indians/Alaska Natives during 2014–2015.
During 2000–2015, the rise in the P&S syphilis rate was primarily attributable to increased cases among men and, specifically, among MSM. In 2015, men accounted for over 90% of all cases of P&S syphilis. Of those male cases for whom sex of sex partner was known, 81.7% were MSM. Reported cases of P&S syphilis continued to be characterized by a high rate of HIV co-infection, particularly among MSM. In the 31 states able to classify at least 70.0% of reported P&S syphilis cases as MSM, men who have sex with women (MSW), or women and at least 70.0% of reported cases as HIV-positive or HIV negative, 49.8% of MSM with P&S syphilis were also reported as HIV-positive compared with 10.0% of cases among MSW and 3.9% of cases among women.
The 2013 rate of congenital syphilis (9.2 cases per 100,000 live births) marked the first increase in congenital syphilis since 2008. During 2013–2014, the rate increased 27.2% and during 2014–2015 increased 6.0%, primarily attributable to an increase in the West. There were 487 cases of congenital syphilis reported in 2015 compared with 461 in 2014. Rates of congenital syphilis were highest among Blacks (35.2 cases per 100,000 live births), followed by Hispanics (15.5 cases per 100,000 live births) and American Indians/Alaska Natives (10.3 cases per 100,000 live births).
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. Sexually transmitted diseases treatment guidelines, 2015. MMWR Morb Mortal Wkly Rep 2015; 64(No. RR-3): 1–137