Sexual health

The PrEP Shot — How Long-Acting Injectable Prevention Works

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For anyone who finds a daily pill hard to keep up, injectable PrEP moves HIV prevention from something you do every morning to something a clinician does for you every couple of months. Here is how the shot works, how well it protects, what each visit involves, why it still leaves other STIs uncovered, and what the long tail means when you decide to stop.

Last updated: July 2026

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How does the PrEP shot (Apretude) work?

Injectable PrEP is the medicine cabotegravir, given as a shot into the muscle by a healthcare provider rather than taken as a daily pill. It is long-acting: after a starter phase of injections spaced closer together, the shot is repeated roughly every two months, and between visits it keeps enough drug in the body to block HIV from taking hold 1. It is one of the covered prep options for HIV prevention, sitting alongside the daily oral pills 1. The appeal is straightforward — instead of a pill to remember every day, protection becomes an appointment a few times a year. Cabotegravir is the drug itself; Apretude is the brand name it is sold under.

How well does injectable PrEP work?

Injectable PrEP delivers the same class of protection as oral PrEP: taken as prescribed, PrEP reduces the risk of getting HIV from sex by about 99% 1. For the shot, "as prescribed" means kept on schedule — the injections given on time so drug levels never dip into a vulnerable range. Its real-world strength lies exactly there: a shot you receive every couple of months is much harder to miss than a pill you must remember daily, so the everyday gap between ideal use and actual use narrows. The injectable's advantage is not a higher ceiling of protection but a lower chance of missed doses. The most protective option, for any given person, tends to be the one they can keep up with. That is also why counseling around the shot leans so heavily on scheduling: the protection is essentially locked in for as long as the appointments are.

Who is injectable PrEP for?

Injectable PrEP is an option for the same people any PrEP is: sexually active adults and adolescents who could be exposed to HIV. The 2021 clinical practice guideline recommends that clinicians inform all sexually active people about PrEP and match the method to the person 2. The shot particularly suits people for whom a daily pill is hard — because remembering is a struggle, because a pill bottle raises privacy concerns at home, or because pill fatigue has set in. If you are still weighing whether PrEP is for you at all, the groundwork is the same question as what is prep for hiv, applied to a different delivery. And if cost is the worry, many people ask about free prep or getting prep without insurance, which are worth raising directly with a prescriber.

What happens at each injection visit?

Each dose of injectable PrEP is given by a provider — it is not something you administer yourself at home. That structure is deliberate: the guideline builds regular HIV testing and monitoring into PrEP, and the injection visits become the natural moment to do it 2. Before starting, and at the visits, confirming HIV-negative status matters, because injectable PrEP is a prevention drug and not a treatment for an existing infection 1. The rhythm is a starter phase of injections spaced closer together, then a maintenance shot roughly every two months 1. Missing a scheduled injection, or drifting late, is the main thing to guard against, since that is what opens a gap in protection — clinics often book the next appointment before you leave for exactly that reason.

What injectable PrEP does not do

Injectable PrEP protects against HIV and nothing else. It offers no protection against gonorrhea, chlamydia, syphilis, herpes, or HPV 1, so barrier methods and routine STI screening still have a role for people on the shot. Some people at higher risk of bacterial STIs also use doxy-PEP — a separate, after-sex antibiotic approach the CDC counsels for certain men who have sex with men and transgender women with a recent bacterial STI — which the shot does not replace 3. And injectable PrEP is prevention, not treatment: it is for people who do not have HIV. A partner who does have HIV protects others in a different way — by taking treatment to an undetectable viral load, which carries effectively no risk of transmission 4.

How do you start injectable PrEP?

Starting the shot begins the way starting any PrEP does: a visit, a confirmed HIV-negative test, and a conversation about which method fits, all of which the guideline builds into how PrEP is initiated and monitored 2. Some clinicians open with a short oral lead-in — a stretch of daily pills first, to make sure the medicine is tolerated — before the first injection, while others move straight to the shot; that choice is individual and made with the prescriber. From there, the starter phase and the every-two-month rhythm take over. If you already take oral PrEP and want to switch, that is a planned handoff rather than a fresh start, timed so protection never lapses. The practical first move is simply asking a prescriber whether injectable PrEP is available to you and how the schedule would look for your situation.

Stopping the shot: the long tail

The same long-acting quality that makes injectable PrEP convenient also makes stopping it a decision that needs planning. After the last injection, cabotegravir leaves the body slowly over many months, and during that decline the drug level can fall below what fully protects while still lingering in the system — a stretch sometimes called the pharmacologic tail. That matters for two reasons the guideline addresses: ongoing HIV testing has to continue through the tail, and anyone with continued risk needs a bridge, such as switching to daily oral PrEP, so there is no unprotected gap 2. If a specific high-risk exposure happens during that window, it becomes a PEP situation — post-exposure prophylaxis started as soon as possible and within 72 hours of the exposure 5. Coming off the shot is reasonable and common; it simply is not the same-day decision that stopping a pill can feel like.

Common questions

After a starter phase of injections spaced closer together, injectable PrEP is given roughly every two months by a healthcare provider. It is not self-administered. Because protection depends on staying on schedule, clinics often book the next visit before you leave. Drifting late on an injection is the main thing to avoid, since that is what can open a gap in coverage.

Neither is simply better; they suit different lives. Both oral and injectable PrEP are highly effective when used as prescribed. The shot removes the daily-pill burden, which helps people who struggle to remember or want more privacy. The pills offer flexibility, including on-demand dosing for some. The best option is usually the one a person can keep up with most reliably.

No. Like all PrEP, the shot targets HIV alone and does nothing against gonorrhea, chlamydia, syphilis, herpes, or HPV. Barrier methods and routine STI screening still matter for people on injectable PrEP, and some higher-risk people additionally use doxy-PEP for bacterial STIs. The shot handles HIV; the other infections need their own tools.

Cabotegravir leaves the body slowly, so after your last shot the drug level declines over months — a period called the tail, where protection fades before the drug is fully gone. Ongoing HIV testing continues through that window, and if you still have risk, a bridge like daily oral PrEP prevents an unprotected gap. Stopping is best planned with a clinician rather than simply skipped.

No. Injectable PrEP is given by a healthcare provider, partly because it is an intramuscular injection and partly because each visit is the built-in moment for the HIV testing and monitoring that PrEP requires. That clinical touchpoint is a feature, not just a hurdle — it keeps prevention paired with the testing that makes it safe.

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When the PrEP shot needs a same-day call to your clinic

  • —Flu-like illness — fever, sore throat, rash, swollen lymph nodes — in the weeks after a missed or delayed injection, which can signal acute HIV
  • —A high-risk exposure during the tail after stopping the shot, before another form of protection is in place
  • —Severe or spreading redness, swelling, or pain at the injection site, or a fever in the days after an injection

Trouble breathing, facial or throat swelling, or fainting after an injection is a medical emergency — call 911 or go to the nearest emergency room.

This article explains how injectable PrEP works; it is general education, not medical advice, and it names no specific dose. Whether injectable PrEP fits you, how it is scheduled, and how to stop it safely are decisions for a qualified clinician who knows your history.

References

  1. 1.Centers for Disease Control and Prevention (2024). Clinical Guidance for PrEP. CDC HIV Nexus. linkThat PrEP taken as prescribed reduces the risk of getting HIV from sex by about 99%, that injectable cabotegravir is a covered PrEP option alongside oral pills, and that PrEP does not protect against other STIs.
  2. 2.Centers for Disease Control and Prevention / US Public Health Service (2021). Preexposure Prophylaxis for the Prevention of HIV Infection in the United States - 2021 Update: A Clinical Practice Guideline. CDC (stacks.cdc.gov). linkThat the 2021 U.S. clinical practice guideline recommends informing sexually active adolescents and adults about PrEP and building regular HIV testing and monitoring into PrEP care, including planning to avoid gaps in protection.
  3. 3.Centers for Disease Control and Prevention (2024). Doxy PEP for Bacterial STI Prevention. CDC (cdc.gov/sti). linkThat doxy-PEP is a separate after-sex antibiotic approach the CDC counsels for certain men who have sex with men and transgender women with a recent bacterial STI — a tool for bacterial STIs that PrEP does not cover.
  4. 4.Centers for Disease Control and Prevention (2024). Undetectable = Untransmittable. CDC Global HIV and TB. linkThat a person with HIV who maintains an undetectable viral load has effectively no risk of sexually transmitting HIV (U=U) — the way a partner with HIV protects others.
  5. 5.Centers for Disease Control and Prevention (2024). Clinical Guidance for PEP. CDC HIV Nexus. linkThat HIV PEP must be started as soon as possible and within 72 hours of exposure and is the emergency option for a one-time exposure — relevant to a gap during the injectable's tail.

5 sources, numbered by first appearance. General health information, not medical advice. AI-assisted editorial content — citations link their sources. Editorial policy

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