Pre-Exposure Prophylaxis (PrEP)

Quick Guide: 2021 PrEP Update
prevention one pager

This factsheet summarizes CDC’s 2021 update to the Preexposure Prophylaxis for the Prevention of HIV Infection in the United States—A Clinical Practice Guideline. The updates in this version of the guideline give health care providers the latest information on prescribing pre-exposure prophylaxis (PrEP) for HIV prevention to their patients and increasing PrEP use by people who could benefit from it.

Download factsheet pdf icon[PDF – 370 KB]

Clinicians’ Quick Guide

Preexposure Prophylaxis for the Prevention of HIV Infection in the United States – 2021 Update – A Clinical Practice Guideline

The Centers for Disease Control and Prevention (CDC) has released the Preexposure Prophylaxis for the Prevention of HIV Infection in the United States—2021 Update—A Clinical Practice Guideline. The updates in this version of the guideline give health care providers the latest information on prescribing pre-exposure prophylaxis (PrEP) for HIV prevention to their patients and increasing PrEP use by people who could benefit from it. The revisions also:

  • Update guidance based on current evidence.
  • Include information on recent approvals of PrEP medications by the US Food and Drug Administration (FDA).
  • Clarify some aspects of clinical care.
  • Make the guideline simpler to use so that health care providers can apply it more easily.

Below are key changes in the updated PrEP guideline.

What Are the New Graded Recommendations?

Grade Ia

Prescribe cabotegravir (CAB) injections as PrEP for sexually active adults. The FDA approved CAB for PrEP in 2021. CAB may be right for people:

    • Who had problems taking oral PrEP as prescribed.
    • Who prefer getting a shot every 2 months instead of taking oral PrEP.
    • Who have serious kidney disease that prevents use of other PrEP medications.
Grade IIIb

Inform all sexually active adults and adolescents that PrEP can protect them from getting HIV. Providers should offer PrEP to anyone who asks for it, including sexually active adults who do not report behaviors that put them at risk for getting HIV. Telling all sexually active adults and adolescents about PrEP will increase the number of people who know about PrEP. Talking about PrEP may also help patients overcome embarrassment or stigma that may prevent them from telling their health care provider about behaviors that put them at risk for getting HIV.

What Are the Key Changes in the Updated PrEP Guideline?

flowchart icon

Patients Who Should Be Prescribed PrEP

More easily identify patients who would benefit from PrEP. The updated guideline includes flow charts offering a few questions about sexual or drug injection behaviors that might put patients at risk of getting HIV.

Syringe icon

HIV Laboratory Tests

Quickly test patients who are starting or taking PrEP. The updated guideline includes two testing algorithms:

  • For patients who are starting or restarting PrEP after a long stop, test using an HIV antigen/antibody test (laboratory-based is preferred).
  • For patients who are taking or have recently taken PrEP (including patients who have taken oral PrEP in the last 3 months or patients who had a CAB injection in the last 12 months), test using an HIV antibody/antigen assay AND a qualitative or quantitative HIV-1 RNA assay.
  • If a patient has a positive antigen/antibody test and a detectable HIV-1 RNA test confirming the patient has HIV, link that patient to HIV care and treatment.
  • If a patient has a negative antigen/antibody test and an undetectable HIV-1 RNA test confirming the patient does not have HIV, continue prescribing PrEP.
Syringe icon

Oral Prep Options

Prescribe emtricitabine (F)/tenofovir disoproxil fumarate (TDF) (Truvada® or generic equivalent) or consider the additional option of prescribing emtricitabine (F)/tenofovir alafenamide (TAF) (Descovy®) for sexually active men and transgender women. In 2019, the FDA approved F/TAF as PrEP for sexually active men and transgender women. The updated guideline adds F/TAF as a PrEP option for these groups. F/TAF is not recommended for people assigned female sex at birth who could get HIV through receptive vaginal sex.

graph icon

Ongoing Assessments

For oral PrEP
CDC revised the recommended assessments for patients taking oral PrEP as follows:

  • Assess creatinine clearance once every 12 months for patients under age 50 or patients whose estimated creatinine clearance was greater than 90 mL/min when they started oral PrEP.
    • For all other patients, assess creatinine clearance every 6 months.
  • For patients taking F/TAF, Each year, measure patients’ triglyceride and cholesterol levels and their weight.
  • Review the list of medications that may interact with F/TAF or F/TDF

For injectable PrEP (cabotegravir, or CAB)
Because the FDA approved CAB for PrEP in 2021, the updated guideline includes a new section that details the ongoing assessments and follow-up schedule for patients taking CAB.

  • Regular kidney, triglyceride, or cholesterol assessments are not needed for patients taking CAB as they are for patients taking oral PrEP.
  • The follow-up schedule for recommended assessments is different for CAB users:
    • HIV testing every 2 months (at each injection visits)
    • STI testing every 4 months (at every other injection visit)

What Are Other Considerations for Providing PrEP?

calendar icon

Same-day PrEP

Offer same-day PrEP to patients when appropriate. The updated guideline offers steps to safely prescribe PrEP to patients on the same day as their first evaluation. These steps include:

  • Conducting baseline assessments and tests.
  • Offering information on insurance or co-pay assistance.
  • Scheduling follow-up tests and appointments.
  • Giving or prescribing oral PrEP or CAB injections.
TeleMed icon


Provide PrEP by telehealth when available. The guideline includes options for offering PrEP services by telehealth, such as having telephone or web-based visits, using laboratory or home testing, and prescribing a 90-day supply of PrEP medication.

Icon - 2-1-1

2-1-1 Dosing

Learn about 2-1-1 dosing. The guideline now provides information on how to correctly use off-label 2-1-1 dosing for oral PrEP. This information may benefit gay, bisexual, and other men who have sex with men who choose to use 2-1-1 dosing. This approach is not approved by the FDA and is not recommended by CDC.

doctor icon

Primary Care for PrEP Patients

Address primary care needs during PrEP visits. The updated guideline describes how health care providers can offer primary care services to patients taking PrEP to help prevent and screen for other conditions. These may include STIs, mental health disorders, tobacco/nicotine use, and drug or alcohol use disorders.

To get a PDF version of the information below and access other print resources for your practice and patients, visit our PrEP/PEP materials page.

What is PrEP?

PrEP is short for pre-exposure prophylaxis. It is the use of antiretroviral medication to prevent acquisition of HIV infection. PrEP is used by people without HIV who are at risk of being exposed to HIV through sexual contact or injection drug use. Two medications have been approved for use as PrEP by the FDA. Each consists of two drugs combined in a single oral tablet taken daily:

  • Emtricitabine (F) 200 mg in combination with tenofovir disoproxil fumarate (TDF) 300 mg (F/TDF – brand name Truvada®)
  • Emtricitabine (F) 200 mg in combination with tenofovir alafenamide (TAF) 25 mg (F/TAF – brand name Descovy®)

These medications are approved to prevent HIV infection in adults and adolescents weighing at least 35 kg (77 lb) as follows:

  • Daily oral PrEP with F/TDF is recommended to prevent HIV infection among all persons at risk through sex or injection drug use.
  • Daily oral PrEP with F/TAF is recommended to prevent HIV infection among persons at risk through sex, excluding people at risk through receptive vaginal sex. F/TAF has not yet been studied for HIV prevention for receptive vaginal sex.

PrEP should be considered part of a comprehensive prevention plan that includes a discussion about adherence to PrEP, condom use, other sexually transmitted infections (STIs), and other risk reduction methods.

What are the guidelines for prescribing PrEP?

Comprehensive guidelines for prescribing PrEP have been published by the Centers for Disease Control and Prevention (CDC) in A Clinical Practice Guidelinepdf icon,[1] including a Clinical Providers’ Supplementpdf icon.[2]

The Clinical Providers’ Supplement contains additional tools for clinicians providing PrEP, such as a patient/provider checklist, patient information sheets, provider information sheets, a risk incidence assessment, supplemental counseling information, billing codes, and practice quality measures. If questions arise or if prescribing advice is needed, clinicians should consult the National Clinicians Consultation Center PrEP Line @ 1-855-448-7737 (9:00 AM – 8:00 PM EST).

The U.S. Preventive Services Task Force has given PrEP a grade A recommendation.[3] This grade indicates that their review found that there is high certainty that the net benefit of this service is substantial. For more information, view the full recommendation rationale at www.uspreventiveservicestaskforce.orgexternal icon.

Who can prescribe PrEP?

Any licensed prescriber can prescribe PrEP. Specialization in infectious diseases or HIV medicine is not required. In fact, primary care providers who routinely see people at risk for HIV acquisition should consider offering PrEP to all eligible patients.[4]

To whom should I offer PrEP?

PrEP is for people without HIV who are at risk of acquisition from sex or injection drug use. People at risk who should be assessed for PrEP include:

  • Sexually active gay and bisexual men without HIV
  • Sexually active heterosexual men and women without HIV
  • Sexually active transgender persons without HIV
  • Persons without HIV who inject drugs
  • Persons who have been prescribed non-occupational post-exposure prophylaxis (PEP) and report continued risk behavior, or who have used multiple courses of PEP
Approaches to Address Barriers
Sexually-Active Adults and Adolescents Persons Who Inject Drugs
Anal or vaginal sex in the past 6 months; and
HIV-positive sexual partner (especially if partner has unknown or detectable viral load); or
Recent bacterial STI; or
History of inconsistent or no condom use with sexual partner(s)
HIV-positive injecting partner; or
Shares drug preparation or injection equipment
Documented negative HIV test result before prescribing PrEP; and
No signs/symptoms of acute HIV infection; and
Normal renal function; and
No contraindicated medications


Download or order clinician and patient materials from CDC's Let's Stop HIV Together campaign

How is PrEP prescribed?

PrEP is FDA-approved to be taken once daily by mouth.[5,6] Full prescribing information is available at iconexternal icon and iconexternal icon.

(See Clinical Providers’ Supplement, Section 5: icon)

What is the evidence base for PrEP?

Multiple studies have demonstrated that PrEP is highly effective when taken as prescribed.

Approaches to Address Barriers
Transmission Route Effectiveness Estimate Interpretation
Sexual ~99% Very high levels of adherence to PrEP ensures maximum effectiveness.
Injection drug use 74% – 84% These estimates are based on tenofovir alone and not necessarily when taken daily. The effectiveness may be greater for the two-drug oral therapy and if used daily.


For more information on evidence related to daily, consistent, and on-demand PrEP use, visit

How important is adherence to PrEP?

To be effective, PrEP requires high levels of adherence. When taken as prescribed, oral PrEP is extremely effective in preventing HIV.[7] A few cases of HIV infection have been reported among MSM whose high adherence to PrEP was verified. These rare cases indicate that the risk of HIV acquisition with high adherence to PrEP is extremely low, but not com­pletely eliminated.

Based on existing research, PrEP reaches maximum protection from HIV for receptive anal sex at about 7 days of daily use. For receptive vaginal sex and injection drug use, PrEP reaches maximum protection at up to about 21 days of daily use.

Is PrEP safe?

Yes. PrEP has not caused serious short- or medium-term safety concerns.[8,9,10]  F/TDF as PrEP is considered generally safe for pregnant and breastfeeding women.[6] Providers and patients who are or may become pregnant and have concerns should decide together if the risk of ongoing HIV transmission through sex or drug injection is sufficiently high to use PrEP knowing that pregnancy is associated with an increased risk of HIV acquisition.[11]

Since F/TDF and F/TAF are eliminated by the kidneys, PrEP should only be used in patients without renal impairment (see Renal Function, below). It should be co-administered with care in patients taking other drugs eliminated by the kidneys (e.g., acyclovir, adefovir dipivoxil, cidofovir, ganciclovir, valacyclovir, valganciclovir, aminoglycosides, and high-dose or multiple NSAIDs). Drugs that decrease renal function may also increase serum concentrations of tenofovir or emtricitabine.[5,6]

Who should not be prescribed PrEP?

  • People with HIV. Individuals must be confirmed as HIV-negative before initiating PrEP. Excluding persons with acute HIV infection is critically important, as there is a risk of developing resistant HIV if they are inadvertently started on PrEP. F/TDF and F/TAF are appropriate components of a regimen to treat HIV but must be combined with additional antiretrovirals to provide effective treatment.
  • People with renal insufficiency. Providers should confirm that the patient’s estimated creatinine clearance is ≥60 mL/minute (Cockcroft-Gault formula) before initiating F/TDF as PrEP, or ≥30 mL/minute before initiating F/TAF as PrEP.

What baseline assessment is required for individuals beginning PrEP?

HIV Testing

HIV testing is required to confirm that patients do not have HIV infection when they start taking PrEP. While antigen/antibody tests are preferred, at a minimum, clinicians should document a negative antibody test result within the week before initiating (or re-initiating) PrEP medications. The required HIV testing can be accomplished by (1) drawing blood and sending the specimen to a laboratory for testing or (2) performing a rapid, point-of-care FDA-approved fingerstick blood test. Oral rapid tests should not be used to screen for HIV infection when considering PrEP use because they can be less sensitive than blood tests.[12] A listing of FDA-approved HIV tests, specimen requirements, and time to detection of HIV infection are available online at:

Since PrEP is indicated for individuals who report sexual or injection behaviors that place them at risk of HIV acquisition, clinicians should suspect acute HIV infection in persons known to have been exposed recently. Clinicians should solicit a history of signs or symptoms of viral infection during the preceding month or on the day of evaluation in all PrEP candidates with a negative or an indeterminate result on an HIV antibody test.

For patients with signs/symptoms of acute HIV infection within the prior four weeks, the following options are suggested:

  1. Test patient with a combination antibody/antigen assay, ideally with a laboratory-based method. If the test is non-reactive (negative), PrEP can be initiated.
  2. Test patient with a viral load (VL) assay. If the patient has a measurable VL <3,000 copies/mL infection is unlikely, but PrEP should be deferred while testing is repeated. If the VL is below the level of detection of the assay, and the patient has no signs/symptoms on that day, PrEP can be initiated.
  3. Defer PrEP and retest patient for HIV antibody in one month.

Renal Function

When used as PrEP, TDF-containing regimens can cause decreases in renal function that are typically small and of unknown clinical significance, and that also typically reverse with discontinuation of the drug [5,6]. Occasional cases of acute renal failure, including Fanconi’s syndrome, have occurred. [13-20] Therefore, all persons considered for PrEP must have their renal function assessed at treatment initiation as well as periodically thereafter so that PrEP can be stopped, if necessary.  Renal function should be assessed using the Cockcroft-Gault formula and the patient’s serum creatinine value to calculate an estimated creatinine clearance (eCrCl).  F/TDF is approved for use in persons with a eCrCl >60 ml/min. F/TAF is approved for use in persons with eCrCl ≥30 ml/min.

Hepatitis B Serology

Emtricitabine and tenofovir can be used to treat HBV, and discontinuation of these medicines can cause rebound hepatitis. HBV infection is not a contraindication to PrEP, but all persons considered for PrEP with F/TDF or F/TAF must be screened for HBV; if they start PrEP, when they stop the medication their liver function can be closely monitored for reactivation of HBV replication that could result in hepatic damage.

Graphic: PrEP Baseline Assessment algorithm

What additional support and ongoing assessments are required for patients on PrEP?

Prescribe PrEP as part of a combination prevention plan. At minimum, while patients are on PrEP, CDC guidelines recommend:

Provide the following services
Provide the following services:
At 3 months after PrEP initiation:
  • Test for HIV.
  • Measure serum creatinine and estimate creatinine clearance.
  • Provide medication adherence and behavioral risk reduction support.
  • Additionally, for
    • MSM: screen for bacterial STIs*;
    • Women with reproductive potential: test for pregnancy; and
    • PWID: assess access to sterile needles/syringes and to drug treatment services.
Every 3 months after the first 3-month follow-up:
  • Test for HIV.
  • Provide medication adherence and behavioral risk reduction support.
  • Additionally, for
    • MSM: screen for bacterial STIs*;
    • Women with reproductive potential: test for pregnancy; and
    • PWID: assess access to sterile needles/syringes and to substance use disorder treatment services.
Every 6 months after the first 3-month follow-up:
  • Measure serum creatinine and estimate creatinine clearance.
  • For all sexually active patients: Screen for bacterial STIs*.

*Nucleic Acid Amplification Test (NAAT) to screen for gonorrhea and chlamydia based on anatomic site of exposure; blood test for syphilis.

How will my patients pay for PrEP medication, clinical visits, and lab tests?

Most insurance plans and state Medicaid programs cover PrEP. Prior authorization may be required.

Patient assistance program: There are medication assistance programs that provide free PrEP medications to people with no insurance to cover PrEP care. To learn more, call 855-447-8410 or visit www.getyourprep.comexternal icon

Co-pay assistance program: Income is not a factor in eligibility. More information is available at: icon Some states have their own PrEP assistance programs. Some cover medication, some cover clinical visit and lab costs, some cover both. To learn more visit: icon

How should a patient who acquires HIV infection while taking PrEP be managed?

Once additional laboratory tests have confirmed infection, the following steps should be taken:

    • Initiate treatment or refer for comprehensive HIV care.
  • Counsel the patient about how to prevent HIV transmission to others and to improve their own health.
  • Report the new HIV infection to the local health department.

To learn more about HIV treatment, see: /preventioniscare

HIV and Coronavirus Disease 2019 (COVID-19)

Resources for people at risk or with HIV, clinicians, and public health partners.

How do I provide PrEP Services during COVID 19?

CDC has developed guidance for providing PrEP when facility-based services and in-person patient-clinician contact is limited. For programs experiencing disruption in PrEP clinical services, CDC offers the following guidance for clinics to consider in the context of local resources and staff availability.

  1. Clinicians should continue to ensure the availability of PrEP for patients newly initiating PrEP and patients continuing PrEP use.
  2. Quarterly HIV testing should be continued for patient safety. Lab-only visits for assessment of HIV infection and other indicated tests for the provision of PrEP are preferred. When these are not available or feasible, CDC recommends considering two additional options:
    • Some laboratories (such as Molecular Testing LabsTMexternal icon) have validated protocols for testing home-collected samples for the panel of tests required for those initiating or continuing PrEP. This laboratory-conducted test is sensitive enough to detect recent HIV infection.
    • The second option is self-testing via an oral swab-based test. Although this type of HIV self-test is usually not recommended for PrEP patients due to its lower sensitivity in detecting recent HIV infection during PrEP use, clinicians could consider use of these tests when other options are not available.
  3. When HIV-negative status is confirmed, consider providing a prescription for a 90-day supply of PrEP medication (rather than a 30-day supply with two refills) to minimize trips to the pharmacy and to facilitate PrEP adherence. Several programs are available to help provide affordable PrEP medication including Ready, Set, PrEPexternal icon, a nationwide program that makes PrEP medications available at no cost to individuals who qualify and lack prescription drug coverage; state drug assistance programs; and Gilead’s Medication Assistance Program (MAP)external icon, which assists eligible HIV-negative adults in the United States who require assistance paying for PrEP.
  4. If a PrEP clinic is considering closing or suspending services temporarily, health care providers should establish referral relationships with other clinics, telemedicine services, or pharmacies so that clients may remain engaged in PrEP care.

If PrEP clinical services have not been disrupted, providers should continue to follow recommendations outlined in the 2021 PrEP Clinical Guidelines pdf icon[PDF – 2 MB] and Clinical Providers’ Supplement pdf icon[PDF – 809 KB]. To further ensure safe delivery of critical public health services, CDC has issued guidance for protecting public health workers engaged in public health activities that require face-to-face interaction.

Read the full Dear Colleague Letter on PrEP during COVID-19.

  1. Centers for Disease Control and Prevention (CDC), US Public Health Service. Preexposure Prophylaxis for the Prevention of HIV Infection in the United States—2017 Update: A Clinical Practice Guideline. CDC website. icon. Published March 2018. Accessed June 2, 2019.
  2. CDC. Clinical Providers’ Supplement. Pre-Exposure Prophylaxis for the Prevention of HIV Infection in the United States. 2017. icon Published March 2018. Accessed June 2, 2019.
  3. US Preventive Services Task Force. Preexposure Prophylaxis for the Prevention of HIV Infection: US Preventive Services Task Force Recommendation Statement. JAMA.2019;321(22):2203–2213.
  4. Krakower D, Mayer KH. What primary care providers need to know about preexposure prophylaxis for HIV prevention: a narrative review. Annals Int Med. 2012 Oct 2;157(7):490-7.
  5. Gilead Sciences. Descovy Package Insert. 2019. iconexternal icon. Accessed November 7, 2019.
  6. Gilead Sciences. Truvada Package Insert. 2016. da_pi.pdfpdf iconexternal icon. Accessed August 8, 2016.
  7. Riddell IV J, Amico KR, Mayer KH. HIV Preexposure Prophylaxis: A Review. JAMA 2018;319:1261-68.
  8. Grant RM, Anderson PL, McMahan V, et al. Uptake of pre-exposure prophylaxis, sexual practices, and HIV incidence in men and transgender women who have sex with men: a cohort study. Lancet 2014;14:820-9.
  9. Baeten JM, Donnell D, Ndase P, et al. Antiretroviral prophylaxis for HIV prevention in heterosexual men and women. N Engl J Med 2012;367:399-410.
  10. Donnell D, Baeten JM, Bumpus NN, et al. HIV protective efficacy and correlates of tenofovir blood concentrations in a clinical trial of PrEP for HIV prevention. J Acq Immun Def Syndr 2014;66:340.
  11. Thomson KA, Hughes J, Baeten JM, John-Stewart G, Celum C, Cohen CR, Ngure K, Kiarie J, Mugo N, Heffron R. Increased risk of female HIV-1 acquisition throughout pregnancy and postpartum: a prospective per-coital act analysis among women with HIV-1 infected partners. The Journal of infectious diseases. 2018 Mar 5.
  12. Deutsch MB, Glidden DV, Sevelius J, et al. HIV pre-exposure prophylaxis in transgender women: A subgroup analysis of the iPrEx trial. Lancet HIV 2015;2(12):e512-e519.
  13. Molina J-M, Charreau I, Spire B, et al. Efficacy, safety, and effect on sexual behaviour of on-demand pre-exposure prophylaxis for HIV in men who have sex with men: an observational cohort study. Lancet HIV 2017;4:e402-10.
  14. Antoni G, Tremblay C, Charreau I, et al. On-demand PrEP with TDF/FTC remains highly effective among MSM with infrequent sexual intercourse: a sub-study of the ANRS IPERGAY trial. Presented at: IAS Conference on HIV Science; July 23-27, 2017; Paris, France.
  15. Saag MS, Benson CA, Gandhi RT, et al. Antiretroviral drugs for treatment and prevention of HIV infection in adults: 2018 recommendations of the International Antiviral Society-USA Panel. JAMA. 2018;320(4):379-396.
  16. Mugwanya KK, Wyatt C, Celum C, et al. Changes in glomerular kidney function among HIV-1-uninfected men and women receiving emtricitabine-tenofovir disoproxil fumarate preexposure prophylaxis: a randomized clinical trial. JAMA Intern Med. 2015 Feb;175(2):246-54.
  17. Mugwanya KK, Wyatt C, Celum C, et al. Reversibility of Glomerular Renal Function Decline in HIV-Uninfected Men and Women Discontinuing Emtricitabine-Tenofovir Disoproxil Fumarate Pre-Exposure Prophylaxis. J Acquir Immune Defic Syndr. 2016 Apr 1;71(4):374-80.
  18. Tang EC, Vittinghoff E, Anderson PL, et al. Changes in Kidney Function Associated With Daily Tenofovir Disoproxil Fumarate/Emtricitabine for HIV Preexposure Prophylaxis Use in the United States Demonstration Project. J Acquir Immune Defic Syndr. 2018 Feb 1;77(2):193-198.