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.

If something happened in the last few days that could have exposed you to HIV, there is a medical option that works against the clock. It is called post-exposure prophylaxis, or PEP. This guide walks you through what to do and where to go in Chicago.

Take a breath. Time matters, but you have steps you can follow, and people at clinics and emergency departments do this every day.

What PEP is and why the 72-hour window matters

PEP is emergency HIV medication. A clinician prescribes it after a possible exposure to HIV. It is meant to lower the chance that HIV takes hold in the body.

The CDC says PEP should be started as soon as possible, and within 72 hours of a possible exposure. After 72 hours, the CDC says it is not recommended to start. Every hour inside that window counts, so the first move is to act, not to wait and see.

PEP is for emergencies. It is not meant to be a regular way to prevent HIV. If you expect to need protection on an ongoing basis, a clinician can talk with you about PrEP, which is a different approach.

PEP is a prescription. This page does not cover what the medicine is or how it is taken, because a clinician sets that after talking with you.

Who might be asked about PEP

The CDC describes PEP for people who may have been exposed to HIV in the last 72 hours. This can include sex without a condom, a condom that broke, sharing needles or other drug equipment, or sexual assault.

Whether PEP makes sense for your situation is a decision for a clinician. They will ask about what happened, when it happened, and what is known about the other person. You do not need to have all the answers.

PEP is for people of every gender and orientation. No one at a clinic needs you to explain or defend your life. The questions are there to help them choose care.

What you need before you go

You do not need much. A short list helps the visit go faster.

The time of the possible exposure. Write down the day and your best guess of the hour. The 72-hour count starts there.
A phone. You may need to call ahead, and a clinician may call you back with results.
Your insurance card, if you have one. The Chicago Department of Public Health (CDPH) asks insured patients to bring a card, and says care is provided regardless of ability to pay or insurance status.
A list of medicines you take. Include supplements and anything prescribed. A clinician checks this before choosing PEP.
Notes on your health. Mention kidney or liver problems, pregnancy or chances of pregnancy, and allergies.
A way to get home and a plan for the next few weeks. A course of PEP lasts weeks, so think about where you will keep it and how you will remember it.

If you are missing something, go anyway. A missing insurance card or a vague timeline should not delay care.

Step-by-step: how to get PEP in Chicago

Step 1: Note the time and go the same day

Count forward from the possible exposure. The CDC window is 72 hours. If you are inside it, today is better than tomorrow.

If you are unsure whether you are inside the window, ask a clinician anyway. They can tell you what is possible. It is their call, not yours, and not something to decide alone at home.

Step 2: Choose where to go based on the time of day

Where you go depends on what is open. Here are the main routes.

Any hour: a hospital emergency department. Emergency departments are open at all hours, so this is the route for nights, weekends and holidays. Tell the triage staff you are there about a possible HIV exposure and want to ask about PEP. This guide does not name specific hospitals, since the health department sources it relies on do not list emergency department PEP services. If you are unsure which is closest, call the Illinois HIV/STD Hotline at 1-800-243-2437, listed on the Illinois Department of Public Health (IDPH) STD page.
Daytime walk-in: a sexual health clinic. Howard Brown Health lists PEP among the services on its sexual health walk-in clinic page.

Howard Brown says there is no appointment necessary at its walk-in clinic and that patients are seen first come, first served. It lists three Chicago locations on that page:

Location	Address	Phone
Howard Brown Health Sheridan	4025 N. Sheridan Rd., Chicago, IL 60613	773.388.1600
Howard Brown Health 63rd St.	641 W. 63rd St., Chicago, IL 60621	773.388.1600
Broadway Youth Center	1023 W. Irving Park Road, Chicago, IL 60613	773.388.1600

The Broadway Youth Center is Howard Brown's youth site. Howard Brown's site menu describes youth services for ages 12 to 24. The walk-in page used for this guide does not list hours for these sites, so call 773.388.1600 to confirm hours before you go. If the clinic is closed or the window is closing, use an emergency department.

Howard Brown describes its walk-in clinic as quick and low cost, and offers a Sliding Fee Discount Program based on income and family size. The page does not list a price for PEP, so ask the clinic about cost when you call or check in.

The CDPH Sexual Health Specialty Clinics offer HIV testing, PrEP and treatment. The CDPH page does not say that PEP is offered at these sites, so if you are inside the window, call the clinic first and ask. CDPH lists these locations:

Lakeview North Clark Street Health Clinic, 2849 N. Clark St., 1st Fl., 312.744.5507
Austin West Division Street Health Hub, 4909 W. Division St., Suite 411, 312.746.4871
Roseland East 115th Street Health Hub, 200 E. 115th St., 1.5 fl., 312.747.1090

CDPH says to call for an appointment, that limited walk-ins are available, and that the clinics are closed from 12 to 1 pm daily and on City holidays. It also says to call the clinic to verify hours. Because the PEP window is short, a call before you travel is worth the minute.

Step 3: Say it plainly at check-in

You can say something like this: "I had a possible HIV exposure and I would like to ask about PEP." You do not have to share more than you want to at the front desk.

With the clinician, the more clearly you describe the timing, the better they can help. Honest answers help them choose care. They are not there to judge.

Step 4: Expect a test and a conversation first

The CDC says a clinician should do an HIV test before PEP begins. This is not a sign that anyone expects a particular result. It gives a starting point for later comparison. A clinician may also offer tests for other sexually transmitted infections, and may talk with you about pregnancy.

A rapid HIV test may be available at some sites. Howard Brown lists rapid HIV testing among its services. Ask about it, but do not let waiting for a result delay a PEP decision. That sequence is for the clinician to manage.

If you are 12 or older, Illinois law lets you consent to care related to the prevention, diagnosis or treatment of sexually transmitted diseases without a parent. This comes from the Illinois Consent by Minors to Health Care Services Act (410 ILCS 210/4). The statute also says providers make reasonable efforts to involve family if they believe it will not be harmful, and that each STD incident is reported to public health.

Step 5: Start the course as your clinician directs

If a clinician prescribes PEP, ask how soon to start. The CDC's guidance is to begin as soon as possible, so many people start the same day. Ask whether you leave with the medicine in hand or need to pick it up, and where.

The CDC says a PEP course lasts 28 days. Your clinician will explain exactly how to take it. This guide does not give amounts or schedules, because those come from your prescription.

Ask these questions before you leave:

When should I take the first dose, and what if I miss one?
What side effects are common, and when should I call?
Who do I call with questions during the 28 days?
When are my follow-up appointments?

Step 6: Finish the full course

The CDC's PEP guidance is built around a full 28-day course. Stopping early may reduce how well PEP works. If side effects make it hard to continue, call your clinician before you stop. They may have options.

Some people notice nausea, tiredness or headaches. Not everyone does. Your clinician can tell you which symptoms are expected and which need a call.

Step 7: Keep your follow-up testing appointments

The CDC's PEP guidance includes follow-up HIV testing after the course so that your result can be confirmed over time. Your clinician sets the exact dates and tells you which tests to get. Put them on your calendar before you leave the clinic.

Between the start of PEP and your final test, the CDC recommends taking steps to avoid passing HIV to others while the picture is still unclear. That can include using condoms. A clinician can talk this through with you in plain terms.

Tips that make the process easier

Call first when you can, but do not let a phone tag stop you. If no one answers in time, go to an emergency department.
Write down the clinic's name and number after your visit, along with your follow-up dates.
Set daily phone alarms for the 28-day course. Tie the time to something you do anyway, like brushing your teeth.
Ask about cost before you leave and ask about financial help. Howard Brown lists a sliding fee program, and CDPH says care is provided regardless of ability to pay.
Bring a friend if that helps. A second person can remember instructions and keep you company.
Ask about prevention going forward. A clinician can explain PrEP, and Illinois has PrEP4Illinois, a medication assistance program run by IDPH. Helpline: 1-833-773-7445.

Common mistakes to avoid

Waiting to see if symptoms appear. The CDC window is based on time since exposure, not symptoms. Many people with HIV have no early symptoms, so waiting does not give you useful information.
Going to a clinic that may be closed. Hours change. CDPH itself says to call to verify hours. A short call saves a trip.
Assuming the 72 hours is flexible. The CDC window is a limit. If you think you are close to it, go straight to an emergency department.
Stopping the course when you feel fine. Feeling fine is not a reason to stop. Follow your prescription and talk with your clinician before changing anything.
Skipping follow-up tests. The tests after the course are part of PEP, not an extra.
Taking someone else's medicine or leftover medicine. PEP is chosen and prescribed for you by a clinician.
Letting shame make the choice. Seeking PEP is a responsible, common health step. Clinicians are there to help, not to judge.

What results to expect

PEP is not a guarantee, and no medicine or test is perfect. The CDC says PEP can lower the chance of HIV infection when it is started promptly and taken as prescribed. How well it works can depend on how soon it starts, whether the full course is completed, and the type of exposure.

Many people take PEP and have negative follow-up tests. Your clinician will explain what each result means for you. If a follow-up test were positive, that is also a medical situation with good options. HIV is not curable, but it is treatable, and the CDC says effective treatment helps people with HIV stay healthy. A clinician can connect you to care the same day.

You may also leave your visit with other things to follow up on, such as tests for other infections. Bacterial infections like chlamydia, gonorrhea and syphilis are curable with treatment from a clinician. Ask which tests were done and when results come back.

Chicago context

HIV is part of life in this city, and so is care for it. IDPH's December 2025 HIV Surveillance Update reports 474 new HIV diagnoses in the Chicago Health Department jurisdiction from January 1 to December 31, 2025. IDPH labels these figures provisional and subject to change, so the final number may be higher.

The point is not to scare anyone. It is that clinics, hotlines and emergency departments in Chicago deal with these questions all the time. You are not the first person to walk in with this question.

Illinois no longer has an HIV-specific criminal statute. The Illinois General Assembly records that Criminal Transmission of HIV (720 ILCS 5/12-5.01) was repealed by Public Act 102-168, effective July 27, 2021. That means seeking testing or PEP does not put you at legal risk under that law.

After PEP: free and low-cost testing in Chicago

Once the urgent part has passed, regular testing is a good habit. Our guide to STD testing in Chicago, including where to get tested and what it costs lists clinics, services and cost information in one place.

A few options worth knowing:

Cook County Health's Ruth M. Rothstein CORE Center, 2020 W. Harrison St., Chicago, IL 60612, has a walk-in STI Screening Clinic. Cook County Health says to call Monday to Friday, 8:30am to 3:30pm, at 312-572-4700, and that same-day HIV and STI services are provided. CDC GetTested lists sliding scale fees there. The sources used for this guide do not state that PEP is offered at this site, so ask when you call.
Erie Family Health Centers offers a free rapid HIV test kit by online request or by phone at 312-386-6344. It is for Illinois residents age 17 or older, and it covers HIV only, not other infections. A home test is not a substitute for the follow-up testing your PEP clinician sets.
CDC GetTested at gettested.cdc.gov lets you look up testing sites by location.

Quick reference

Write down when the possible exposure happened.
Go the same day. The CDC window is 72 hours.
Use an emergency department at any hour, or call a clinic first during the day.
Expect a conversation and an HIV test before PEP starts.
Take the 28-day course exactly as your clinician directs.
Keep every follow-up testing appointment.
Ask about cost help and about longer-term prevention.

For questions at any point, the Illinois HIV/STD Hotline is 1-800-243-2437. You can also see the Chicago Department of Public Health's sexual health services page for current clinic information.

PEP in Chicago: Emergency HIV Prevention Within 72 Hours