STD Rates in Cook County, Illinois

2023 CDC surveillance data for Cook County, Illinois — chlamydia, gonorrhea, and syphilis rates with state comparisons.

Data Year: 2023 Source: CDC STI Surveillance Population: 5,087,215
Combined
1127.1
per 100K
6th / 102
Chlamydia
790
per 100K • 40,189 cases
US rate: 490.7
5th of 102 in Illinois
Higher than 92% of US counties
Gonorrhea
319.7
per 100K • 16,265 cases
US rate: 178.2
7th of 102 in Illinois
Higher than 93% of US counties
Syphilis P&S
17.4
per 100K • 884 cases
US rate: 15.8
14th of 102 in Illinois
Higher than 76% of US counties

Cook County has one of the higher STD burdens in Illinois, with a combined rate of 1,127.1 per 100,000 residents in 2023 — ranking 6th of 102 counties. Reported infections included chlamydia at 790.0 per 100,000 (40,189 cases, 42% above the state rate), gonorrhea at 319.7 per 100,000 (16,265 cases, 58% above the state rate), syphilis at 17.4 per 100,000 (884 cases, 50% above the state rate). Confidential STD testing is available throughout Cook County — knowing your status is the only way to catch infections that often show no symptoms.

STD Trends in Cook County, 2000–2023

Reported cases per 100,000 residents each year, against the Illinois rate (dashed). In a county this size a handful of cases moves the rate a long way, so read the shape rather than any single year.

Chlamydia
790.0
per 100K in 2023
458.5 in 2000
Peak 881.8 in 2019
Gonorrhea
319.7
per 100K in 2023
327.4 in 2000
Peak 353.0 in 2019
Syphilis (P&S)
17.4
per 100K in 2023
6.1 in 2000
Peak 21.1 in 2018

Source: CDC NCHHSTP AtlasPlus county surveillance, 2000–2023.

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Cook County vs Illinois and the US

Infection Cook County Illinois US vs Illinois vs US Rank in Illinois
Chlamydia 79040,189 cases 557.7 490.7 41.7% above 61% above 5th of 102
Gonorrhea 319.716,265 cases 202.3 178.2 58% above 79.4% above 7th of 102
Syphilis (P&S) 17.4884 cases 11.6 15.8 50% above 10.1% above 14th of 102

Rates per 100,000 residents, 2023. Ranks run from the highest rate (1st) among Illinois’s counties. The US rate is all 50 states combined. Comparisons are left out where fewer than 20 cases were reported, because a rate built on so few cases can swing widely from one year to the next.

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FAQs

Cook County ranks 6th of 102 Illinois counties for combined STD rate in 2023, at 1,127.1 per 100,000 residents.
In 2023, chlamydia was the most frequently reported STD in Cook County, with 40,189 cases at a rate of 790.0 per 100,000 residents.
STDTest.com lists confidential testing locations across Cook County and Illinois. Many offer same-day appointments with results in 1–3 days.
Data sourced from the CDC's annual STI Surveillance Report. Rates are per 100,000 population and reflect reported cases only — actual prevalence is likely higher due to undiagnosed infections. While we strive for accuracy, STDTest.com makes no representations or warranties regarding the completeness or accuracy of this data and is not responsible for any errors or omissions. This page is for informational purposes only and does not constitute medical advice.