Condom broke? Your HIV risk and what to do

A broken condom counts as no condom

Condoms are very good at preventing HIV. Across real-world use they lower the risk of sex by about 80%, and that figure already includes the times condoms break or slip. But for the one act where the condom failed, it’s safest to assume it gave no protection.

That doesn’t mean HIV was passed on. For that to happen, your partner has to have HIV and the virus has to pass to you during that act. Most of the time, at least one of those doesn’t happen.

Your risk from one act

These are average estimates for one act without a condom, with a partner who has HIV and isn’t on treatment:

• Receptive anal sex (bottom): 1.4% (about 1 in 72)
• Insertive anal sex (top): 0.11% (about 1 in 910)
• Receptive vaginal sex: 0.08% (about 1 in 1,200)
• Insertive vaginal sex: 0.04% (about 1 in 2,500)

If you don’t know your partner’s status, the chance is much smaller, because most people don’t have HIV. In the United States, for example:

• A woman having vaginal sex with a man of unknown status: 0.00014% (about 1 in 730,000)
• A man having vaginal sex with a woman of unknown status: <0.0001% (about 1 in 1,500,000)
• A man bottoming with a man of unknown status: 0.05% (about 1 in 2,000)

If your partner has HIV and keeps an undetectable viral load on treatment, they can’t pass HIV on through sex. That’s the basis of U=U.

What can change the estimate

• When it broke. If the condom came off or tore but your partner didn’t ejaculate inside you, risk is lower. The calculator lowers the estimate by 50% when there was no ejaculation.
• Other STIs. Infections that cause sores or inflammation, such as syphilis or herpes, make HIV easier to pass on. The calculator multiplies the estimate by 2 if either of you has one.
• Recent infection. In the first weeks after someone gets HIV, their viral load is very high. The calculator raises the estimate 10 times if your partner was recently infected.
• PrEP. If you take PrEP (pre-exposure prophylaxis) as prescribed, it lowers the risk by about 99% for anal sex and about 90% for vaginal sex. A broken condom is then far less of a worry.

What to do now

1. Decide about PEP quickly. PEP is a 28-day course of HIV medicines that can stop the virus from taking hold. It must start within 72 hours, and sooner is better. The calculator estimates that PEP started within 24 hours cuts the remaining risk by about 90%. After 72 hours it’s no longer recommended, but see what to do after 72 hours.
2. Don’t wait for a test result first. A test right now can’t show an infection from this exposure. If you start PEP, the clinic will do a baseline test, and you don’t need to wait for the result.
3. Talk to your partner if you can. Knowing whether they have HIV, and whether they’re on treatment with an undetectable viral load, changes the picture a lot.
4. Test after the window period. Each HIV test type needs time before it can pick up a new infection:

If your first test falls inside the window, test again after it closes. If you take PEP, expect follow-up HIV tests about 4 to 6 weeks and 12 weeks after the exposure. Our test accuracy by week guide explains what a negative result means at each point.

5. Think about STIs too. A broken condom can also pass on other infections, so it’s worth asking about STI testing at the same visit.

Looking ahead

Most broken condoms don’t lead to HIV. If condom accidents happen more than once, or you have partners whose status you don’t know, PrEP is worth asking about. It protects you even when a condom fails. And if you’re feeling anxious while you wait for results, you’re not alone: our page on HIV anxiety may help.