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.

PrEP is medicine that lowers the chance of getting HIV. This guide explains how PrEP works, who it is for, how to get it in St. Louis, and what to expect on cost. It is written for anyone in the city or St. Louis County, whatever your gender, orientation or relationship status.

You do not need to have everything figured out before you ask. A clinician can walk you through it. This page gives you enough background to make that conversation easier.

Contents

What PrEP is and how well it works
Who PrEP is for
Types of PrEP: daily pills, event-based use and injections
How to get PrEP: the visit, the lab tests and follow-up
HIV PrEP cost and how to pay for it
Where to start in St. Louis
Staying on PrEP and the rest of your sexual health
Sources

Key takeaways

PrEP is prescribed by a clinician. It is for people who do not have HIV and want to lower their chance of getting it.
The CDC says daily oral PrEP reduces the risk of getting HIV from sex by about 99 percent when taken as prescribed. For injection drug use, the CDC says the reduction is at least 74 percent.
Starting PrEP involves an HIV test, a few other lab tests and regular follow-up visits.
The USPSTF recommends PrEP for people at increased risk of HIV. Under the Affordable Care Act, most private plans must cover recommended preventive services like this without cost sharing. Check your own plan for details.
In St. Louis, Planned Parenthood Great Rivers, CareSTL Health and the WashU Infectious Diseases Village Square Clinic list PrEP services. Call first to confirm what is available and what it costs.
The City of St. Louis Health Stop offers free HIV testing, which is a common first step.

What PrEP is and how well it works

PrEP stands for pre-exposure prophylaxis. In plain terms, it is HIV prevention medicine taken before a possible exposure. The name tells you the timing: "pre" means before.

PrEP is for people who do not have HIV. It does not treat HIV. A person who already has HIV needs a different set of medicines, and a clinician decides that.

How PrEP works

PrEP medicines keep HIV from taking hold in the body if the virus gets in. For this to work, there has to be enough medicine in your body at the time of exposure. That is why using PrEP the way your clinician prescribes it matters so much.

What the CDC says about effectiveness

The CDC says daily oral PrEP reduces the risk of getting HIV from sex by about 99 percent when taken as prescribed. The CDC also says it reduces the risk of getting HIV from injection drug use by at least 74 percent.

Those numbers describe people who use PrEP as directed. Results are lower when doses are missed. No prevention method works in every situation, so it helps to think of PrEP as one strong tool among several.

What PrEP does not do

PrEP does not protect against other sexually transmitted infections such as chlamydia, gonorrhea, syphilis or herpes. It also does not prevent pregnancy. Condoms, regular STI testing and vaccines still play a role, and we cover those below.

Why it matters in St. Louis

The City of St. Louis Fast-Track Cities HIV data page reported 108 new HIV diagnoses in St. Louis City in 2021, a rate of 36.0 per 100,000 people. For St. Louis County it reported 143 new diagnoses, or 15.0 per 100,000. Missouri as a whole was reported at 633 new diagnoses, or 10.0 per 100,000.

These numbers show that HIV prevention is a local matter. They say nothing about any one person. Your own situation is what counts, and a clinician can talk it through with you.

Who PrEP is for

PrEP is not for one type of person. It is for anyone who does not have HIV and could benefit from extra protection. That includes people of every gender and orientation, in any kind of relationship.

What the CDC and USPSTF describe

The CDC's clinical guidance for PrEP says clinicians should discuss it with sexually active adults and adolescents, and with people who inject drugs. The USPSTF recommends that clinicians offer PrEP to people at increased risk of getting HIV. Clinicians look at things such as:

Having a partner who has HIV, especially if that partner is not on treatment or the viral load is not suppressed
Having more than one sex partner, or a partner whose HIV status you do not know
Having had a bacterial STI recently
Not using condoms consistently
Sharing needles, syringes or other injection equipment
Wanting extra protection for any reason, including while trying to conceive with a partner who has HIV

You do not have to fit a category to ask about PrEP. If you are curious, you can say so. A clinician will ask questions to understand your situation, and the choice is yours.

Couples and partners

The CDC says that a person with HIV who takes treatment and keeps the virus at an undetectable level does not pass HIV to sex partners. Some couples still choose PrEP for the partner without HIV, especially while viral suppression is being reached. This is a conversation to have with a clinician.

Pregnancy and trying to conceive

PrEP can be part of a safer-conception plan. If you are pregnant, planning a pregnancy or chestfeeding, tell the clinician. They can explain how PrEP fits and which options make sense.

Teens and young adults

Missouri law at Mo. Rev. Stat. 431.061 lets a minor consent to treatment for venereal disease. The statute lists no minimum age. The law as written does not mention PrEP by name. If you are under 18, ask the clinic directly what it requires. Clinics follow their own consent policies.

When PrEP is not the right tool right now

A clinician will check your HIV test result and kidney function before prescribing. If a test shows something that needs attention, the clinician will explain the options. Only a test and a clinician can tell you where you stand.

Types of PrEP: daily pills, event-based use and injections

There is more than one way to take PrEP. The right one depends on your body, your life, your health history and what is available. Ask your clinician which fits you.

Daily oral PrEP

This is a pill taken once a day. It is the most studied form. The CDC's PrEP guideline describes tenofovir-based combination medicines for this purpose. A clinician chooses the product and tells you how to take it.

The CDC says daily PrEP works best when taken consistently. Many people tie it to something they already do each day, like brushing teeth. Phone alarms help too.

Event-based (on-demand) oral PrEP

Some people have heard of an on-demand approach, sometimes called "2-1-1." It means taking PrEP around sex rather than every day. It is not the same as daily use, and the CDC does not describe it as an option for everyone.

The CDC notes that this approach is not approved by the FDA. The research behind it was done mainly in men who have sex with men. The CDC describes it only for that group. It is not described for people who have vaginal sex, for people who inject drugs, or for those with certain health conditions such as hepatitis B. If you think it might fit you, ask a clinician. They can tell you whether it is appropriate and how it would be taken.

Injectable PrEP

Injectable PrEP is a shot given by a clinician at a clinic. It replaces taking a pill each day. The CDC's guideline includes an injectable form, and newer injectable options may have become available since. Because this field changes, ask a clinician which injectable options they offer and whether you qualify.

Injections can suit people who find daily pills hard, or who prefer fewer touchpoints with medicine. They do require keeping follow-up appointments on time. Missing appointments can leave gaps in protection, so be honest about what you can manage.

Side effects

Many people have no side effects. Some report mild stomach upset, headache or tiredness early on. Injections can cause soreness where the shot is given. Tell your clinician about anything that worries you. Do not stop on your own without checking in, because stopping changes your protection.

How long until it protects you

PrEP does not work instantly. The time it takes to reach protection depends on the type and on the kind of sex. Ask your clinician how long to wait and what to use in the meantime. If you want the CDC's own explanation, see its PrEP page at cdc.gov/hiv/basics/prep.html.

How to get PrEP: the visit, the lab tests and follow-up

PrEP needs a prescription or an injection from a clinician. You cannot buy it over the counter. The process is usually less complicated than people expect.

Step 1: Pick a place and call

You can start with a primary care provider, a community health center, a sexual health clinic or a Planned Parenthood health center. Call ahead. Ask whether they prescribe PrEP, whether you need an appointment, and what the visit costs. Hours and walk-in policies change, so confirm before you go.

Step 2: The first visit

Expect a private, nonjudgmental conversation. A clinician will ask about your health, medicines and sexual and drug-use history. These questions help them choose the right option. You can answer as much as you feel comfortable with, and you can bring up concerns.

You do not need to explain or justify yourself. Wanting to prevent HIV is a reasonable health choice.

Step 3: The lab tests

The CDC's PrEP guideline calls for lab work before and during PrEP. Typical tests include:

An HIV test. This is required before starting. PrEP is only for people who test negative, because someone with HIV needs a different treatment plan.
Kidney function. Some oral PrEP medicines can affect the kidneys, so clinicians check.
Hepatitis B and hepatitis C tests. These affect which medicine is safe and what other care you may need.
STI testing. Depending on the kind of sex you have, this can include tests for gonorrhea, chlamydia and syphilis, from urine, swabs or blood.
A pregnancy test, if it applies to you.

Some clinics can do a rapid HIV test and give a result in minutes. Others use a blood draw with results later. Ask which they use.

Step 4: Starting and follow-up

After your results, the clinician prescribes PrEP or schedules your first injection. The CDC says people on PrEP should come back for follow-up, with HIV testing at each check-in, along with checks on side effects, adherence and STI testing. For oral PrEP, the CDC's guideline describes follow-up about every three months. Your clinician will tell you what applies to you.

Follow-up is not a hurdle. It is how a clinician keeps PrEP safe, confirms you remain HIV-negative, and catches other health issues early.

What if you need protection after a recent exposure?

PrEP is for before. If you may have been exposed to HIV in the past few days, a different medicine called PEP (post-exposure prophylaxis) exists. The CDC says PEP must be started within 72 hours of a possible exposure. It is an urgent matter, so call a clinic or go to an emergency department right away. The WashU Infectious Diseases Village Square Clinic lists PEP among its services. Call it to confirm what is available.

Telehealth

Some clinics and telehealth services offer PrEP visits by video or phone. This guide does not recommend a specific service. If you go this route, make sure you can get lab tests done and that the provider is a licensed clinician. Your local clinic can also tell you what it offers remotely.

HIV PrEP cost and how to pay for it

Cost is the most common worry. The honest answer is that it depends on your insurance, your income and where you go. This section explains the main pieces.

Insurance and the Affordable Care Act

In 2023 the USPSTF issued a grade A recommendation for PrEP for people at increased risk of HIV. Under the Affordable Care Act, most private health plans must cover services with an A or B grade without charging you a copay or deductible. Federal guidance has said this covers the PrEP medicine as well as related services such as HIV testing, kidney tests and clinic visits.

There are limits. Some plans are grandfathered. Some do not follow ACA rules. Medicaid and Medicare have their own rules. Call the number on your insurance card and ask what is covered for PrEP and the related lab work. Ask the clinic's billing staff, too.

If you are uninsured or underinsured

You still have options. The Missouri Department of Health and Senior Services (DHSS) HIV, STI and Hepatitis program has a PrEP page with general information and a link to the CDC's "Paying for PrEP" resource. You can reach the program at 888-252-8045 or [email protected]. The DHSS page does not describe a Missouri-specific PrEP payment program, so check with the program about what is currently available.

The CDC's resource lists general ways people pay, including assistance programs offered by drug makers and community programs. Clinics that serve uninsured patients often have staff who know how to apply. Ask for a navigator or benefits specialist.

Sliding-scale clinics

Several St. Louis clinics list sliding-scale fees, meaning the price is tied to income. In the CDC's GetTested directory, Planned Parenthood Great Rivers and CareSTL Health both list insurance, Medicaid and sliding scale. A WashU news article from May 2024 describes a CDC-funded expansion in north St. Louis County aimed at walk-in testing at no or low cost. None of these sources gives a dollar price for PrEP, so ask each clinic what you would pay.

Questions to ask about cost

Is the visit covered, and what is my copay?
Are the lab tests covered?
Is the medicine or injection covered, and is there a prior authorization step?
Do you have a sliding scale or financial assistance?
Can someone help me apply for help paying for medicine?

If a clinic's page does not list a price, say so when you call and ask for an estimate. You have a right to know before you commit.

Where to start in St. Louis

This list uses the clinics' own published information and the CDC's GetTested directory. Services and hours can change, so call before you go. The City of St. Louis Department of Health does not publish a PrEP page that we could find, so confirm PrEP availability at each place.

Clinic	Address and phone	PrEP-related services listed	Cost and access
Planned Parenthood Great Rivers, Central West End Health Center	4251 Forest Park Ave, Saint Louis, MO 63108; 314-531-7526	PrEP navigation, HIV tests (rapid and blood draw), chlamydia, gonorrhea, syphilis and herpes testing, HPV vaccine	Insurance, Medicaid and sliding scale. The CDC listing says appointment required.
CareSTL Health, Dr. Martin Luther King Health Center	5471 Dr Martin Luther King Dr, Saint Louis, MO 63112; 314-367-5820	PrEP navigation, HIV, chlamydia, gonorrhea and syphilis testing, vaccines	Insurance, Medicaid, Medicare and sliding scale. The CDC listing says appointment required.
WashU Infectious Diseases, Village Square Clinic (Hazelwood)	1 Village Square Shopping Center, Suite 1, Hazelwood, MO 63042; 314-362-9098	PrEP, PEP, doxy-PEP, STI and HIV testing and treatment	Described as walk-in testing at no or low cost. WashU said in 2024 that details were still being worked out, so confirm by phone.

Planned Parenthood Great Rivers

The CDC's GetTested listing shows PrEP navigation along with HIV, herpes, chlamydia, gonorrhea and syphilis testing at the Central West End health center. It lists an appointment as required. The listing shows no hours, so call 314-531-7526 to ask.

CareSTL Health

CareSTL Health is a community health center. Its Dr. Martin Luther King Health Center lists PrEP navigation and testing for HIV, chlamydia, gonorrhea and syphilis in the CDC directory. Call 314-367-5820 for hours and appointments.

WashU Infectious Diseases, Village Square Clinic

This clinic in Hazelwood serves north St. Louis County. WashU's 2024 news article mentions PrEP, PEP and doxy-PEP, plus treatment for walk-in patients and their partners. Neither WashU page lists walk-in hours. Call 314-362-9098 before you travel.

Free HIV testing as a first step

The City of St. Louis Health Stop Testing and Referral Center is run by the City of St. Louis Department of Health at 1520 Market St, Suite 1625, St. Louis, MO 63103. The city says there is no cost and no ID is needed. It lists HIV testing by finger-prick or blood draw, hepatitis C, and gonorrhea, chlamydia and syphilis testing. Rapid tests take about 15 minutes, and STI results take 5 to 7 business days.

The city lists hours of Monday through Thursday, 9 a.m. to 12 p.m. and 1 p.m. to 4 p.m. It is closed on Fridays and city holidays. Walk-ins are subject to availability. The CDC's GetTested listing says an appointment is required, which differs from the city page, so call 314-657-1584 first. The city page does not list PrEP among its services. Health Stop can help with linkage to care, and the city's Linkage to Care Intake Line is 314-356-0200.

The city also gives out free HIV self-test kits at Health Stop and says kits can be ordered by mail through takemehome.org. TakeMeHome.org says it offers free HIV self-tests after a short eligibility screen.

For a fuller list of places to get tested and what they charge, see our guide to STD testing in St. Louis. You can also search the CDC's directory at gettested.cdc.gov.

St. Louis County sexual health care

The Saint Louis County Sexual Health Clinic at 4000 Jennings Station Road, phone 314-615-9736, is listed by WashU Infectious Diseases as a walk-in clinic for STI prevention, testing and treatment. It says everyone is welcome regardless of where you live or insurance status. The listing does not give hours or prices and does not mention PrEP, so call to ask. The Saint Louis County Department of Public Health's John C. Murphy Health Center in Berkeley, 314-615-0500, appears in the CDC directory for vaccines such as HPV, with sliding scale fees and appointments required.

Staying on PrEP and the rest of your sexual health

PrEP works best as part of a broader plan. Here is how the pieces fit.

Taking PrEP consistently

Missed doses lower protection. If daily pills are hard, say so. A clinician can suggest reminders, a different schedule that fits an approved option, or injections. There is no judgment in asking for a different approach.

Regular STI testing

PrEP visits are a natural time to test for other infections. Bacterial STIs such as chlamydia, gonorrhea and syphilis are curable with treatment from a clinician. Herpes and HPV are manageable but not curable. HIV is treatable, not curable.

Local reports show why this matters. The City of St. Louis Department of Health, in an April 2022 news release on CDC data, said gonorrhea rose 5 percent in the city from 2019 to 2020, and gonorrhea and syphilis rates rose 13 percent in St. Louis County over the same period. It also noted that the drop in reported chlamydia in 2020 was attributed to reduced testing during the pandemic. In other words, fewer tests can mean fewer reports, not necessarily fewer infections.

Doxy-PEP

In 2024 the CDC issued guidance on doxycycline taken after sex, called doxy-PEP, to lower the chance of certain bacterial STIs. The CDC describes it for men who have sex with men and transgender women who have had a bacterial STI in the past year. It is prescribed by a clinician, and it does not protect against HIV. Ask whether it applies to you.

Vaccines

Vaccines for hepatitis A, hepatitis B and HPV are part of sexual health care. CareSTL Health, Planned Parenthood Great Rivers and the county health department all list vaccines in the CDC directory. Ask about them at your PrEP visit.

Condoms and other tools

Condoms lower the chance of many STIs and can be used alongside PrEP. People who inject drugs can also use new, sterile equipment each time and ask about syringe service programs. The CDC has details on its HIV prevention pages.

Stopping PrEP

You can stop PrEP when your situation changes. Talk with your clinician first. They will tell you how to stop safely and when to come back for testing. If your risk returns later, you can restart with a new HIV test.

Confidentiality

Clinics treat health information as private. The City of St. Louis Health Stop describes its testing as free and confidential. If you are on someone else's insurance plan, ask how billing statements and explanations of benefits are sent, since those can reach the policyholder.

Common questions

Do I need an HIV test before starting PrEP? Yes. The CDC's guideline calls for an HIV test before prescribing. A free test at the City Health Stop is one way to begin.

Can I get PrEP the same day? Some clinics can, others take a visit or two. Ask when you call.

Is PrEP only for gay and bisexual men? No. The CDC and USPSTF describe it for anyone at increased risk, including women, transgender and nonbinary people, and people who inject drugs.

Does the Missouri law criminalize HIV exposure? Missouri Revised Statutes 191.677 covers knowingly exposing another person to a serious infectious or communicable disease through an activity that poses a substantial risk of transmission. The text does not name HIV. If you have legal questions, talk to a lawyer or a clinic's social worker.

Your next step

If you are thinking about PrEP, one call is enough to begin. Ring a clinic from the table, or start with free HIV testing at the City of St. Louis Health Stop at 314-657-1584. Ask the questions in this guide. You can also look up more places on the CDC's directory at gettested.cdc.gov.

PrEP in St. Louis: How to Get It, What It Costs and Who It Is For