Condoms are a highly-effective method for preventing the transmission of HIV during sex. However, many people don’t use them or don’t use them consistently. Condoms may also break during sex.

If you think you may have been exposed to HIV through sex without a condom, or due to a broken condom, make an appointment with a healthcare provider as soon as possible.

If you see a doctor within 72 hours, you may be eligible to start a medication to reduce your risk of contracting HIV. You can also set up a future appointment to be tested for HIV and other sexually transmitted infections (STIs).

There’s no HIV test that can accurately detect HIV in the body immediately after exposure. There’s a timeframe known as the “window period” before you can be tested for HIV and receive accurate results.

Read on to learn more about preventive medications, how soon after condomless sex it makes sense to be tested for HIV, the main types of HIV tests, and the risk factors of different forms of condomless sex.

There’s a window period between the time a person is first exposed to HIV and when it will show up on different types of HIV tests.

During this window period, a person may test HIV-negative even though they’ve contracted HIV. The window period can last anywhere from ten days to three months, depending on your body and the type of test that you’re taking.

A person can still transmit HIV to others during this period. In fact, transmission may even be more likely because there are higher levels of the virus in a person’s body during the window period.

Here is a quick breakdown of different types of HIV tests and the window period for each.

Rapid antibody tests

This type of test measures antibodies to HIV. The body can take up to three months to produce these antibodies. Most people will have enough antibodies to test positive within three to 12 weeks after contracting HIV. At 12 weeks, or three months, 97 percent of people have enough antibodies for an accurate test result.

If someone takes this test four weeks after exposure, a negative result may be accurate, but it’s best to test again after three months to be sure.

Combination tests

These tests are sometimes referred to as rapid antibody/antigen tests, or fourth generation tests. This type of test can only be ordered by a healthcare provider. It must be conducted at a lab.

This type of test measures both antibodies and levels of the p24 antigen, which can be detected as soon as two weeks after exposure.

In general, the majority of people will produce enough antigens and antibodies for these tests to detect HIV at two to six weeks after exposure. If you test negative at two weeks after you think you may have been exposed, your healthcare provider will likely recommend another test in one to two weeks, as this test can be negative in the very early stage of infection.

Nucleic acid tests

A nucleic acid test (NAT) canmeasure the amount of the virus in a blood sample and provide either a positive/negative result or a viral load count.

These tests are more expensive than other forms of HIV testing, so a doctor will only order one if they think there’s a high chance that a person was exposed to HIV or if screening test results were indeterminate.

There is typically enough viral material present for a positive result one to two weeks after possible exposure to HIV.

Home testing kits

Home testing kits such as OraQuick are antibody tests that you can complete at home using a sample of oral fluid. According to the manufacturer, the window period for OraQuick is three months.

Keep in mind, if you believe you’ve been exposed to HIV, it’s important to see a healthcare provider as soon as possible.

Regardless of what type of test you take after a potential HIV exposure, you should get tested again after the window period has passed to be certain. People at higher risk of contracting HIV should get regularly tested as often as every three months.

How quickly a person is able to see a healthcare provider after exposure to HIV can significantly affect their chances of contracting the virus.

If you believe you’ve been exposed to HIV, visit a healthcare provider within 72 hours. You may be offered an antiretroviral treatment called post-exposure prophylaxis (PEP) that can reduce your risk of contracting HIV. PEP is typically taken once or twice daily for a period of 28 days.

PEP has little or no effect if taken more than 72 hours after exposure to HIV, according to the Centers for Disease Control and Prevention (CDC). The medication isn’t usually offered unless it can be started within the 72 hour window.

During condomless sex, HIV in the bodily fluids of one person may be transmitted to the body of another person through the mucous membranes of the penis, vagina, and anus. In very rare cases, HIV could potentially be transmitted through a cut or sore in the mouth during oral sex.

Out of any type of condomless sex, HIV can most easily be transmitted during anal sex. This is because the lining of the anus is delicate and prone to damage, which may provide entry points for HIV. Receptive anal sex, often called bottoming, poses more risk for contracting HIV than insertive anal sex, or topping.

HIV can also be transmitted during vaginal sex without a condom, although the vaginal lining is not as susceptible to rips and tears as the anus.

The risk of getting HIV from oral sex without using a condom or dental dam is very low. It would be possible for HIV to be transmitted if the person giving oral sex has mouth sores or bleeding gums, or if the person receiving oral sex has recently contracted HIV.

In addition to HIV, anal, vaginal, or oral sex without a condom or dental dam can also lead to transmission of other STIs.

The most effective way to prevent HIV transmission during sex is to use a condom. Get a condom ready before any sexual contact occurs, since HIV can be transmitted through pre-ejaculate, vaginal fluid, and from the anus.

Lubricants can also help reduce the risk of HIV transmission by helping to prevent anal or vaginal tears. The right lubricants also help prevent condoms from breaking. Only water-based lubricants should be used with condoms, because oil-based lube can weaken latex and sometimes cause condoms to break.

The use of a dental dam, a small plastic or latex sheet that prevents direct contact between the mouth and the vagina or anus during oral sex, is also effective at reducing the risk of HIV transmission.

For people who may have a higher risk for contracting HIV, preventive medication is an option. Pre-exposure prophylaxis (PrEP) medication is a daily antiretroviral treatment. It’s recommended for anyone who is sexually active with more than one partner, or is in an ongoing relationship with someone whose HIV status is either positive or unknown.

Although PrEP does provide a high level of protection against HIV, it’s still best to use condoms as well. PrEP provides no protection against STIs other than HIV.

Remember, if you think you may have been exposed to HIV by having sex without a condom, make an appointment to speak to a healthcare provider as soon as possible. They may recommend PEP medication to reduce your risk of contracting HIV. They can also discuss a good timeline for HIV testing, as well as testing for other STIs.