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STDs in America

STIs or STDs in America

This page looks at statistics for syphilis, chlamydia and gonorrhea. Statistics for HIV and AIDS in the USA can be found in our statistics section.

STD reporting in the USA

In the United States the reporting of national surveillance data on Sexually Transmitted Diseases (STDs) does not include all of the most common STDs.

Reporting for gonorrhea and syphilis began in 1941, but chlamydia has only been reported since 1984. The limited data that is reported for genital herpes is available from the National Health and Nutrition Examination Survey (NHANES). There is no data reporting for genital warts or non-specific urethritis (NSU). Data for these diseases are limited to estimates based on private physicians' office practices, which is provided by the National Disease and Therapeutic Index (NDTI).

Cases of STDs reported by state health departments: United States, 1997-2009

Cases of STDs reported by state health departments

Cases of STDs reported by state health departments and rates per 100,000 population: United States, 1997-2009

Primary and secondaryAll stages

Top ten states ranked by rate (per 100,000) of reported STD cases: United States, 2009

RankPrimary and secondary syphilisChlamydiaGonorrhea
1Louisiana (16.8)Mississippi (802.7)Mississippi (246.4)
2Georgia (9.8)Alaska (752.7)Louisiana (204.0)
3Arkansas (9.6)Louisiana (626.4)South Carolina (185.7)
4Alabama (8.9)South Carolina (595.0)Alabama (160.8)
5Mississippi (8.1)Alabama (556.2)Arkansas (156.2)
6Texas (6.8)Delaware (540.4)Illinois (154.7)
7Tennessee (6.5)Arkansas (502.7)North Carolina (150.4)
8North Carolina (6.3)New Mexico (478.4)Michigan (147.0)
9New York (6.1)Tennessee (478.1)Alaska (144.3)
10Illinois (5.8)New York (472.4)Georgia (141.3)

In 2009 there were very high rates of primary and secondary syphilis ( 27.5 per 100,000 population), chlamydia ( 1,106.6 per 100,000) and gonorrhea ( 432.7 per 100,000 population) reported in Washington D.C.

STDs and gender

Of overall chlamydia diagnoses reported in 2009, the rate of infection among women was almost three times higher than the rate among men: 592.2 cases per 100,000 population compared to a rate of 219.3 among men. This is thought to be due to the higher number of women screened for chlamydia. For gonorrhea, the rate among women was 105.5 (cases per 100,000 population) compared to a rate of 91.9 among men. The rate of primary and secondary stage syphilis was higher among men - 7.8 cases (per 100,000) were reported for men in 2009, compared to 1.4 for women.


Increasing numbers of chlamydia infections have made it the most widespread STD in the USA. In 1997 there were 537,904 reported diagnoses, corresponding to a rate of 205.5 per 100,000 population. However, by 2009 the annual total had more than doubled to 1,244,180 and the rate per 100,000 had risen to 409.2.

In 2009, the rate of chlamydia among blacks was 8 times higher than that in whites. Rates among American Indians/Alaska Natives and Hispanics were also higher than among whites.

Cases of chlamydia have increased every year bar one since reporting began in 1984. Much of this rise can be attributed to the expansion of chlamydia screening activities, use of more sensitive screening tests, and improvements in the reporting system. Yet despite such developments, many people who have chlamydia do not know they are infected. Increased availability of urine testing is hoped to increase the number of men tested for chlamydia.


In 1978, the annual number of reported gonorrhea diagnoses reached a record high of 1,013,436 - a rate of 459.7 per 100,000 population. Following decreases each year between 1985 and 1997, the annual number of cases has stayed below 365,000, and the rate below 130.

Although the 2009 rate of 99.1 diagnoses per 100,000 population is one of the lowest ever recorded, gonorrhea remains the second most commonly reported STD in the United States. Moreover, the rate of gonorrhea among blacks was 20.5 times greater than among whites in 2009. American Indian/Alaska Natives and Hispanics are also disproportionately affected.


Numbers of reported primary and secondary syphilis diagnoses have varied widely since reporting began, from a high of 94,957 in 1946 to a low of 5,979 in 2000. This represents a change from 70.9 cases per 100,000 population to 2.1 cases.

Since the turn of the millennium there has been another steady rise in diagnoses of primary and secondary syphilis, most of which have been among men. In 2009 the rate among males was almost six times higher than females and the rate increased by 4% among males between 2008 and 2009. Most cases of syphilis have occurred among men who have sex with men (MSM).

During 2008 and 2009, the rate of primary and secondary syphilis increased by 11.6% among non-Hispanic blacks, 6.7% among Asian/Pacific Islanders and 4.3% among American Indians/Alaska Natives. The rate decreased by 4.5% among non-Hispanic whites and 2.2% among Hispanics.

Syphilis is a localised infection, with 69.9% of counties reporting no cases at all in 2009.


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