This page is general health information, not medical advice. It cannot tell you whether you have an infection. A clinician can, and the testing options on this site are a good place to start.

STD rates can look like a scoreboard, but they are really a record of who was tested, who was diagnosed and what was reported. This guide walks through the latest published figures for Chicago and Illinois, explains how to read them, and points to free and low-cost testing.

Every number below comes with its year and its source. Where a figure is not published, the guide says so instead of filling the gap.

Key takeaways

The Illinois Department of Public Health (IDPH) reported a 2022 chlamydia rate of 1,023.7 per 100,000 people for the City of Chicago, from 27,596 cases.
The 2022 Chicago gonorrhea rate was 459.3 per 100,000, from 12,382 cases, per the same IDPH table.
Primary and secondary syphilis in Chicago was 29.9 per 100,000 in 2022 (806 cases). Early syphilis overall was 62.6 per 100,000 (1,687 cases), per IDPH.
For Illinois as a whole, CDC's 2023 surveillance tables show chlamydia at 557.7 and gonorrhea at 202.3 per 100,000.
IDPH's provisional December 2025 update counts 474 new HIV diagnoses in the Chicago Health Department jurisdiction. That count will likely rise as late reports arrive.
Rates reflect reported cases, so they are shaped by how much testing happens. Testing is available at several Chicago clinics that accept people regardless of ability to pay or offer sliding fees.

In this guide

How to read STD rates
Chicago chlamydia, gonorrhea and syphilis rates
Illinois rates and comparing by state and by city
HIV diagnoses in Chicago and Illinois
Year-on-year change and what drives rates
Prevention tools and Illinois rules that matter
Free and low-cost testing in Chicago
Sources

How to Read STD Rates

A few ideas make every table in this guide easier to understand.

What a rate per 100,000 means

A rate per 100,000 takes the number of reported cases and scales it to a population of 100,000 people. This lets a city of millions be compared with a smaller county or a whole state.

Chicago is large, so its raw case counts are large. The rate is the fairer way to compare places of different sizes.

Where the numbers come from

Illinois law makes several infections reportable. According to the Illinois Administrative Code (77 Ill. Adm. Code Part 693), AIDS, HIV infection, syphilis, gonorrhea, chlamydia and chancroid are reportable STIs. Health care professionals must report within seven days of diagnosis or treatment.

In Chicago, a city with more than 1,000,000 residents and its own health department, those reports go to the local health department. IDPH and CDC then publish totals built from these reports.

Reported cases are not the same as all infections

A reported case is an infection that someone was tested for, diagnosed with and that a clinic or lab sent to public health. CDC notes that many STIs cause no symptoms, so infections can go unnoticed and unreported.

That means a higher rate can reflect more infections, more testing, or both. A lower rate can reflect fewer infections, less testing, or both. A rate alone cannot tell these apart.

Why the year and the source matter

Different agencies publish on different schedules and use different population estimates. IDPH computes its county and city rates using 2010 U.S. Census population. CDC's state tables are a separate product with their own year.

For that reason, this guide keeps each figure attached to its own year and source. It also avoids setting a 2022 city figure directly against a 2023 state figure as if they were measured the same way.

Chicago Chlamydia, Gonorrhea and Syphilis Rates

The most recent city-level table published by IDPH covers 2018 through 2022. It lists the City of Chicago, under the Chicago Department of Public Health (CDPH) jurisdiction, separately from the rest of Cook County. The table below shows the 2022 figures from that report.

Infection	Chicago 2022 rate per 100,000	Reported cases	Source
Chlamydia	1,023.7	27,596	IDPH STI Section, county table 2018-2022
Gonorrhea	459.3	12,382	IDPH STI Section, county table 2018-2022
Syphilis, primary and secondary	29.9	806	IDPH STI Section, county table 2018-2022
Syphilis, early (all early stages)	62.6	1,687	IDPH STI Section, county table 2018-2022

Chlamydia

Chlamydia is the most commonly reported of the three bacterial infections in these tables. IDPH counted 27,596 Chicago cases in 2022, a rate of 1,023.7 per 100,000.

CDC's 2021 STI Treatment Guidelines describe chlamydia as curable with treatment from a clinician. Because it often has no symptoms, CDC recommends regular screening for some groups, which is one reason case counts run high.

Gonorrhea

IDPH counted 12,382 gonorrhea cases in Chicago in 2022, a rate of 459.3 per 100,000. Gonorrhea is also curable with treatment from a clinician, according to CDC.

Gonorrhea and chlamydia can occur together, and testing for one is often paired with testing for the other. A clinician decides which tests fit a person's situation.

Syphilis

IDPH reports two syphilis measures for Chicago in 2022. Primary and secondary syphilis, the stages most likely to be infectious, came to 29.9 per 100,000 from 806 cases. Early syphilis, which groups together the early stages, came to 62.6 per 100,000 from 1,687 cases.

These two rows should not be added together. The early syphilis row already includes the primary and secondary cases.

CDC's guidelines describe syphilis as curable with treatment from a clinician. Blood tests are the usual way it is detected, and many people have no noticeable signs at some stages.

A note on the city and county rows

IDPH lists Chicago as a sub-jurisdiction of Cook County in its county STI tables. When you see a Cook County figure, check whether it includes Chicago or covers only the area outside the city. The label on the table tells you which.

Illinois Rates and Comparing STD Rates by State and by City

People often search for STD rates by state to see where Illinois stands. CDC publishes a yearly state ranking table in its STI Surveillance Report, and the 2023 edition gives these Illinois figures.

Measure	Illinois 2023	Cases	Rank among states
Chlamydia, per 100,000	557.7	69,992	11th (CDC Table 28)
Gonorrhea, per 100,000	202.3	25,387	13th (CDC Table 19)
Syphilis, primary and secondary, per 100,000	11.6	1,457	Not listed here
Congenital syphilis, per 100,000 live births	77.9	100	Not listed here

All four rows come from CDC's 2023 STI Surveillance Report State Ranking Tables.

What the ranks tell you

Ranks of 11th for chlamydia and 13th for gonorrhea place Illinois in the upper part of the national list by rate. A rank shows position, not cause. It does not say how many people in a given neighborhood are affected, and it does not say how much testing a state does.

Comparing Chicago with Illinois

Chicago's 2022 figures are higher than the state's 2023 figures for chlamydia, gonorrhea and primary and secondary syphilis. That fits a general pattern in which large cities often report higher rates than their states overall, partly because cities concentrate clinics, testing and people.

Still, the two sets of numbers come from different years and different publishers. Treat the comparison as a rough sense of scale, not a precise ratio.

A short guide to comparing STD rates by city

If you want to compare STD rates by city, whether Chicago against another large city or against its own earlier years, a few checks keep the comparison honest.

Match the year. A 2022 figure and a 2023 figure are not a like-for-like pair.
Match the geography. A city, a county and a metro area each count different residents.
Match the infection stage. Primary and secondary syphilis is a narrower measure than early syphilis.
Match the publisher. Each agency may use a different population base.
Remember testing volume. More screening finds more infections, including ones that would otherwise go unnoticed.

CDC has published only national, provisional 2024 STI data so far. State-level 2024 figures were not yet available at the time this guide was written, so the 2023 state numbers are the latest complete set.

Congenital syphilis in Illinois

CDC's 2023 tables list 100 congenital syphilis cases in Illinois, a rate of 77.9 per 100,000 live births. Congenital syphilis happens when syphilis passes from a pregnant person to a baby.

It is preventable when syphilis is found and treated during pregnancy. That is why Illinois law requires prenatal testing, covered in the prevention section below.

HIV Diagnoses in Chicago and Illinois

HIV is reported differently from the bacterial infections above. Public health agencies usually count new diagnoses in a period rather than publish a rate in a quick-reference table.

Place	New HIV diagnoses	Period	Source
Chicago Health Department jurisdiction	474 (provisional)	Diagnosed and reported 1/1/2025 to 12/31/2025	IDPH, December 2025 HIV Surveillance Update Report
Cook County (includes Chicago)	670 (provisional)	Diagnosed and reported 1/1/2025 to 12/31/2025	IDPH, December 2025 HIV Surveillance Update Report
Illinois	1,386	2024	IDPH news release, April 22, 2025

Why the 2025 figures are provisional

IDPH states that all data in its update report are provisional and subject to change. There is a lag between a diagnosis and its report, so the 2025 count is expected to be revised upward.

For that reason, do not read 474 as a final yearly total for Chicago. Do not set it beside the state's 2024 figure of 1,386 either, because the two cover different years and different levels of completeness.

CDPH also publishes an annual HIV data brief. At the time of writing, its figures could not be retrieved for this guide, so none are quoted. The CDPH website is the place to look for the newest brief.

HIV is treatable

HIV is not curable, but it is treatable. CDC explains that effective treatment prescribed by a clinician can keep the amount of virus in the body very low. Testing is the first step, and CDC recommends that everyone from 13 to 64 be tested for HIV at least once, with more frequent testing for people at higher likelihood of exposure.

The U.S. Preventive Services Task Force (USPSTF) also recommends HIV screening for adolescents and adults ages 15 to 65.

Year-on-Year Change and What Drives STD Rates

What the published tables can and cannot show

IDPH's county table covers five years, 2018 through 2022, which allows trend comparisons. This guide quotes the 2022 values because they are the latest. The year-by-year Chicago values for 2018 through 2021 are in the IDPH table itself, and a reader who wants the exact change should open it directly.

The state figures here are CDC's 2023 numbers, and no matching 2022 state values are quoted, so a state year-on-year change is not calculated in this guide. Stating one without the paired values would be guessing.

Be careful with 2020 and 2021 in any trend line. Public health agencies, including CDC, have noted that the COVID-19 pandemic disrupted clinic visits and testing in those years, which affects how reported cases line up from one year to the next.

Common drivers of higher or lower rates

No single factor explains a rate. CDC's surveillance reports describe several that shape what gets reported.

How much testing happens. Screening finds infections that cause no symptoms. A city with more clinics and routine screening will report more cases than a place that tests less.
Access to care. Cost, transportation, clinic hours, insurance and trust in the health system all shape who gets tested and treated promptly.
Time to treatment. Infections that stay untreated can be passed on to others. Quick treatment of a diagnosed infection and of recent partners reduces further spread.
Population size and density. Large cities have many people in a small area, so networks of partners overlap more.
Social and economic conditions. CDC notes that differences in rates between groups often reflect unequal access to health care and other resources, not anything about the people themselves.
Reporting and surveillance. Lab reporting practices and data systems affect which cases are counted and when.

Infections can affect anyone of any gender or sexual orientation who has sex. Rates describe populations, and they say nothing about any one person.

Prevention Tools and Illinois Rules That Matter

Screening recommendations

The CDC STI Treatment Guidelines (2021) recommend routine chlamydia and gonorrhea screening for sexually active women under 25 and for older women with risk factors. They recommend at least yearly screening for gay, bisexual and other men who have sex with men, with more frequent screening for some people. A clinician can say which tests fit your situation.

Doxy-PEP

In 2024, CDC issued guidance on doxycycline taken after sex (doxy-PEP) to lower the chance of certain bacterial STIs for some groups. It is a prescription medicine, and a clinician decides whether it fits a person and how it is used.

IDPH lists doxy-PEP guidance and a fact sheet on its STD page. Howard Brown Health offers doxy-PEP by appointment. It is not described as a walk-in service.

PrEP and PEP

PrEP is medicine that lowers the chance of getting HIV. IDPH runs PrEP4Illinois, a medication assistance program. Its helpline is 1-833-773-7445 (1-833-PREP4IL).

According to IDPH, the program covers Truvada (brand and generic) and Descovy, and Apretude after a provider pre-approval form. It does not cover provider injection fees. It asks for documentation of Illinois residency dated within 90 days and proof of any insurance.

An IDPH statewide standing order, announced April 22, 2025, also allows Illinois residents to get PrEP directly from a trained pharmacist without first needing a doctor's prescription. CDPH Sexual Health Specialty Clinics offer PrEP services by appointment. PEP, which is started after a possible exposure, is listed among services at Howard Brown Health clinics.

Expedited partner therapy

CDC's legal status page for Illinois says expedited partner therapy (EPT) is permissible for chlamydia, gonorrhea and trichomoniasis. Under the Illinois Sexually Transmitted Infection Control Act (410 ILCS 325/6(e)), EPT is limited to partners exposed within the previous 60 days, and the partner must receive counseling and IDPH written materials. Syphilis is not covered.

Consent for young people

Under the Consent by Minors to Health Care Services Act (410 ILCS 210/4), a minor age 12 or older who may have come into contact with a sexually transmitted disease can consent to care or counseling for prevention, diagnosis or treatment. Parental consent is not necessary.

The law also says providers should make reasonable efforts to involve the family if they believe it will not be harmful, and that each STD incident must be reported to public health. Howard Brown's Broadway Youth Center is a walk-in site, and Howard Brown describes its youth services as serving ages 12 to 24.

Prenatal syphilis testing

Illinois's Prenatal Syphilis Act (410 ILCS 320/1) requires syphilis testing at a person's first prenatal exam and again in the third trimester, between 27 and 32 weeks of pregnancy. A woman who objects on religious grounds is exempt from the testing requirement. Birth certificates record whether a test was done, its date and the lab, but never the result.

HIV and Illinois law

Illinois repealed its HIV-specific criminal statute, Criminal Transmission of HIV (720 ILCS 5/12-5.01), through Public Act 102-168, effective July 27, 2021, according to the Illinois General Assembly. For questions about any specific situation, a legal aid organization or attorney is the right contact.

Free and Low-Cost Testing in Chicago

Knowing the rates is useful, but testing is how a person finds out what is going on in their own body. The clinics below are the ones with verified details. For a fuller walk-through of costs and options, see this guide to where to get tested in Chicago and what it costs.

Chicago Department of Public Health Sexual Health Specialty Clinics

CDPH says care at its sexual health clinics is provided regardless of ability to pay or insurance status, and asks insured patients to bring an insurance card. The page does not say the visit is free. Services include STD testing, HIV testing, PrEP and treatment.

The CDPH page says to call for an appointment, notes that limited walk-ins are available, and says clinics close from noon to 1 pm daily and on City holidays. It also says to call the clinic to verify hours.

Lakeview North Clark Street Health Clinic: 2849 N. Clark St., 1st Fl. Phone 312.744.5507. Mon, Wed, Fri 8:00 am to 4:00 pm; Tue and Thu 9:00 am to 5:00 pm.
Austin West Division Street Health Hub: 4909 W. Division St., Suite 411. Phone 312.746.4871. Tue 9:00 am to 5:00 pm; Wed and Fri 8:00 am to 4:00 pm.
Roseland East 115th Street Health Hub: 200 E. 115th St., 1.5 fl. Phone 312.747.1090. Mon and Fri 8:00 am to 4:00 pm; Thu 9:00 am to 5:00 pm.

Howard Brown Health

Howard Brown Health, a nonprofit health center, runs a sexual health walk-in clinic. It describes the service as quick and low-cost, with no appointment necessary and patients seen first come, first served. It also offers a Sliding Fee Discount Program based on income and family size.

Its walk-in page lists testing for HIV (including rapid HIV), syphilis, chlamydia, gonorrhea and hepatitis A, B and C, along with treatment, PEP and PrEP. The phone number for all locations is 773.388.1600.

Sheridan: 4025 N. Sheridan Rd., Chicago, IL 60613.
63rd St.: 641 W. 63rd St., Chicago, IL 60621.
Broadway Youth Center: 1023 W. Irving Park Road, Chicago, IL 60613.

Howard Brown's pages do not list hours in the information gathered for this guide, so call before you go.

Ruth M. Rothstein CORE Center (Cook County Health)

The CORE Center is at 2020 W. Harrison St., Chicago, IL 60612. Cook County Health says its walk-in STI Screening Clinic can be reached by phone Monday through Friday, 8:30 am to 3:30 pm, at 312-572-4700, and that same-day HIV and STI services are provided. Appointments go through the Access Line at 312-572-4500.

The CDC's GetTested listing for this site shows insurance, Medicaid and Medicare accepted, PrEP for uninsured people, and a sliding scale. The same listing mentions rapid HIV testing, hepatitis C testing and HPV vaccine.

Planned Parenthood of Illinois, Rogers Park Health Center

This center is at 5725 N Broadway, Chicago, IL 60660, phone (773) 942-7193. CDC's GetTested listing says an appointment is required and that insurance and Medicaid are accepted. It does not state a self-pay or sliding scale option. CDC advises checking the organization's website for current hours.

A free HIV test kit for Illinois residents

Erie Family Health Centers, a Chicago nonprofit health center, offers a free rapid HIV test kit (OraQuick) by online request or by phone at 312-386-6344. It is for Illinois residents who are 17 or older, and it tests for HIV only, not other STIs. A state or city mail-order program for free HIV or STI home tests was not found.

Find more places on CDC GetTested

CDC's GetTested locator lets you search for HIV and STI testing sites by ZIP code. Listings show services and payment options, but hours can change, so confirm with the site.

Who to call with questions

The Illinois Department of Public Health STD page has statewide information, and the Illinois HIV/STD Hotline is 1-800-243-2437. The Chicago Department of Public Health is the city's health department. A clinician can explain what a test result means and what treatment, if any, they would prescribe.

STD Rates in Chicago: What the Latest Data Shows