Sexually Transmitted Infections

Overview of Sexually Transmitted Infections in Allegheny County, 2022

Sexually transmitted infections (STIs) remain a significant public health burden nationwide and in Allegheny County. In 2021, more than 2.5 million cases of chlamydia, gonorrhea and syphilis were reported in the U.S¹. Together, STIs are estimated to cost the American health care system more than $16 billion in direct medical costs². Significant reductions in new infections are not only possible, but urgently needed to prevent the many negative long-term consequences associated with these infections.

This summary describes four STIs (chlamydia, gonorrhea, syphilis and HIV/AIDS) reported in Allegheny County, focusing primarily on cases reported in 2022. The purpose of this summary is to inform health care providers, policy makers, residents and other community partners about the impact of STIs in the county. Table 1 (below) shows the number of STIs that were reported in Allegheny County in 2021 and 2022. See an infographic with this information(PDF, 510KB).

Table 1. Overview of Reportable STDs in Allegheny County, 2021-2022

Infection	2021	2022	Change from 2021-2022
Chlamydia	5,713	5,594	-2%
Gonorrhea	2,395	2,532	+6%
Early Syphilis Early syphilis includes primary, secondary, and early latent syphilis cases	339	285	-16%
HIV	89	72	-19%

HIV/AIDS

In 2022, there were 72 new cases of HIV reported in Allegheny County. These 72 new cases represent a 19 percent decrease from the 89 new cases reported in 2020 (Figure 1). Most cases were among males (85%) and Black individuals (54%). Eighty-six percent of new HIV cases occurred in those 15-44 years old. Of the 72 new cases, 10 cases (14%) were diagnosed as AIDS within 3 months of the initial HIV diagnosis. The percentage of concurrent cases was higher among females (27%) compared to males (12%).

Figure 1. Newly diagnosed HIV cases in Allegheny County by sex at birth, 2013-2022

Figure 2 shows the number of newly diagnosed HIV cases by sex and age group in 2022. Males aged 25-34 years accounted for 29 (40%) of the new cases, followed by males aged 15-24 years (18%) and males aged 35-44 years (14%). Among the 11 cases in females, 5 (45%) occurred in those aged 35-44 years.

Figure 2. Number of newly diagnosed HIV cases by sex and age group, Allegheny County, 2022

Men who have sex with men (MSM) continued to account for the largest proportion (61%) of new HIV cases in 2022 (Figure 3). However, new cases among this population decreased by 20 percent in 2022 from the number of new diagnoses in 2021. New cases of HIV among individuals with heterosexual contact accounted for 18 percent of all cases in 2022. Cases among heterosexuals decreased by 54 percent from 28 diagnoses in 2021 to 13 diagnoses in 2022. This is the first year that new cases among this population have decreased since 2018.

Figure 3. New cases of HIV in Allegheny County by risk factor, 2022

Syphilis

In 2022, there were 285 reported cases of early syphilis, including 33 cases of primary syphilis, 83 cases of secondary syphilis, and 169 cases of early latent syphilis. Cases of primary, secondary and early latent syphilis all decreased from 2021 to 2022, with an overall 16% decrease. (Table 2).

Table 2. Number of primary and secondary syphilis and early latent syphilis cases reported in Allegheny County, 2013-2022

Year	Primary and Secondary	Early Latent	Total Early Syphilis Cases
2013	28	35	63
2014	68	56	124
2015	129	93	222
2016	87	94	181
2017	58	82	140
2018	58	101	159
2019	71	114	185
2020	140	153	293
2021	139	200	339
2022	116	169	285

Of primary and secondary syphilis cases, 86 percent were among males. The highest rates among males were for those aged 25-39 years (Figure 4). The overall rate among males was 16.9 per 100,000 population, compared to 2.5 per 100,000 population among females. Black persons represented a higher percentage of primary and secondary syphilis cases (52%) compared to white persons (36%), and the rate in Black individuals (41.8 per 100,000 population) was over 9 times the rate in white individuals (4.4 per 100,000 population).

Figure 4. Rate of primary and secondary syphilis infections per 100,000 reported in Allegheny County by sex and age group, 2022

Chlamydia

In 2022, there were 5,594 new cases of chlamydia reported in Allegheny County for a rate of 457.8 per 100,000 population, a 2 percent decrease from 2021. Chlamydia disproportionately affected Black persons with a rate more than 9 times that of white persons among cases with known race. Of all reported cases, 59 percent were among females, and among females, 84 percent were aged 15-29 years. Females 15-24 years had the highest rates of chlamydia, followed by males 20-24 years (Figure 5).

Figure 5. Rate of chlamydia infections per 100,000 reported in Allegheny County by sex and age group, 2022

Gonorrhea

There were 2,532 new cases of gonorrhea reported in Allegheny County in 2022. The rate of 207.3 per 100,000 represents a 6 percent increase from the rate of new infections reported in 2021. Black persons were disproportionately affected by gonorrhea with 49 percent of new infections compared with 29 percent of new infections among white persons; the rate among Black individuals (848.2 per 100,000 population) was 11 times that of white individuals (77.0 per 100,000 population). More cases occurred among males (62%) than among females (38%). The highest rate of infection among males was in those aged 20-24 years, while the highest rate among females was in those aged 15-19 years (Figure 6).

Figure 6. Rate of gonorrhea infections per 100,000 reported in Allegheny County by sex and age group, 2022

References

1. Centers for Disease Control and Prevention. (2021). ‘Sexually Transmitted Disease Surveillance 2021.’ Retrieved from https://www.cdc.gov/std/statistics/2021/default.htm.
2. Centers for Disease control and Prevention. (2022). ‘Incidence, Prevalence, and Cost of Sexually Transmitted Infections in the United States. Retrieved from https://www.cdc.gov/nchhstp/newsroom/fact-sheets/std/STI-Incidence-Prevalence-Cost-Factsheet.html.