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, 1997-2008

Cases of STDs reported by state health departments and rates per 100,000 population: United States, 1997-2008

Year	Syphilis				Chlamydia		Gonorrhea
	Primary and secondary		All stages
	Cases	Rate	Cases	Rate	Cases	Rate	Cases	Rate
1997	8,556	3.1	46,715	17.1	537,904	205.5	327,665	120.2
1998	7,007	2.5	38,290	13.9	614,250	231.8	356,492	129.2
1999	6,617	2.4	35,383	12.7	662,647	247.2	360,813	129.3
2000	5,979	2.1	31,618	11.2	709,452	251.4	363,136	128.7
2001	6,103	2.1	32,284	11.3	783,242	274.5	361,705	126.8
2002	6,862	2.4	32,919	11.4	834,555	289.4	351,852	122.0
2003	7,177	2.5	34,289	11.8	877,478	301.7	335,104	115.2
2004	7,980	2.7	33,422	11.4	929,462	316.5	330,132	112.4
2005	8,724	2.9	33,288	11.2	976,445	329.4	339,593	114.6
2006	9,756	3.3	36,935	12.3	1,030,911	344.3	358,366	119.7
2007	11,466	3.8	40,921	13.6	1,108,374	367.5	355,991	118.0
2008	13,500	4.5	46,277	15.3	1,210,523	401.3	336,742	111.6
Change 2007-2008	18%	18%	13%	12.5%	9%	9%	-5.4%	-6%

Top ten states ranked by rate (per 100,000) of reported STD cases: United States, 2008

Rank	Primary and secondary syphilis	Chlamydia	Gonorrhea
1	Louisiana (16.5)	Mississippi (728.1)	Mississippi (256.8)
2	Alabama (9.7)	Alaska (711.2)	Louisiana (220.2)
3	Georgia (9.6)	South Carolina (597.2)	South Carolina (214.2)
4	Arkansas (7.3)	Alabama (535.0)	Alabama (210.5)
5	Maryland (6.7)	Louisiana (527.8)	North Carolina (176.3)
6	Tennessee (6.7)	Arkansas (498.7)	Georgia (170.5)
7	New York (6.3)	New Mexico (470.2)	Michigan (169.4)
8	Mississippi (6.3)	Hawaii (466.1)	Illinois (160.9)
9	California (6.0)	Illinois (460.4)	Arkansas (159.2)
10	Texas (5.9)	New York (457.9)	Ohio (146.5)

In 2008 there were very high rates of primary and secondary syphilis (24.8 per 100,000 population), chlamydia (1,177 per 100,000 and gonorrhea (451.6 per 100,000 population) reported in Washington D.C.

STDs and gender

Of overall chlamydia diagnoses reported in 2008, the rate of infection among women was almost three times higher than the rate among men: 607.0 cases per 100,000 population compared to a rate of 233.9 among men. This is thought to be due to the higher number of women screened for chlamydia. For gonorrhea, the rate among women was 119.4 (cases per 100,000 population) compared to a rate of 103.0 among men. The rate of primary and secondary stage syphilis was higher among men - 11.1 cases (per 100,000) were reported for men in 2008, compared to 1.5 for women.

Chlamydia

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 2008 the annual total had more than doubled to 1,210,523 and the rate per 100,000 had risen to 401.3.

In 2008, the rate of chlamydia among black men was 12 times higher than that in white men, and was eight times higher in black women than white women. Rates among American Indian/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. It is estimated that the true number of new chlamydia cases occurring each year is around 2.8 million, most of which are not diagnosed. Increased availability of urine testing is hoped to increase the number of men tested for chlamydia.

Gonorrhea

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 2008 rate of 111.6 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 African Americans was 20.2 times greater than among whites in 2008. American Indian/Alaska Natives and Hispanics are also disproportionately affected.

Syphilis

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 2008 the rate among males was five times higher than females, however both men and women experienced an increase between 2007 and 2008. Most cases of syphilis have occurred among men who have sex with men (MSM), but recently there has been an increase among heterosexuals.

In 2008, the rate of primary and secondary syphilis increased by 25.4% among African Americans, 11.9% among Hispanics and 25% among Asian/Pacific Islanders. The rate decreased by 32.4% among American Indian/Alaska Natives.

Syphilis is a localised infection, with 69.3% of counties reporting no cases at all in 2008.

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Sources:

• Centers for Disease Control and Prevention (2009, November) 'Sexually Transmitted Disease Surveillance, 2008', Atlanta, GA: U.S. Department of Health and Human Services