HIV exposure

Updated on:
February 16, 2022

Understand your risks of getting HIV

Somebody’s chance of getting HIV depends on a variety of factors: use of prevention methods, viral load of HIV-positive partners, and sexual behaviour. The higher the count of HIV in somebody’s bloodstream, the higher the likelihood of HIV transmission. The presence of other STIs can also increase one’s risk for HIV transmission 2 to 3 times.

For people who use drugs, the risk of transmission from an injection that has been exposed to HIV is estimated to be between 0.7-0.8%. Sharing drug use equipment, like cookers, and filters during injection use can increase the risk of transmission (even in the absence of sharing needles). The type and frequency of drug use can also impact one’s risk.

If your sexual partner is not on treatment and does not have a suppressed viral load (if they did, there would be no chance of transmission through sex), the chance of HIV transmission varies according to what kind of sex you’re having.

The risk of HIV transmission through receptive anal sex is from 0.5%-3.38%, and 0.06%-0.16% for insertive anal sex. When it comes to receptive vaginal intercourse, there’s a 0.08-0.19% probability of transmission, and 0.05%-0.1% for insertive vaginal intercourse.

For oral sex, the risk if transmission is much lower than for anal and vaginal sex. Findings suggest a low, but non-zero, risk of transmission. This risk can be increased with the presence of oral ulcers, STIs, or trace amounts of blood.

HIV transmission can also happen through breastfeeding, and the probability is of around 9-16%, but decreases if on treatment with an undetectable HIV viral load.

HIV is transmissible without symptoms

HIV starts its journey in the body by infecting immune cells and replicating. As the virus cannot replicate on its own, it uses CD4 T cells in our immune system to create more versions of itself. About two-thirds of new HIV cases express symptoms of acute infection, such as fever, chills, rashes, muscle aches, sore throat, etc. These symptoms can last from a few days to a few weeks and not everybody experiences them.

When the acute (early) HIV infection settles down, the body’s immune system goes back to its regular functioning and the viral load lowers. This ‘in-between time’ can take months or even years and you might show no symptoms. However, HIV is still transmissible during this time if you are not on treatment and your HIV viral load is not undetectable. 

Get tested for HIV

How do I get tested for HIV?

One of the most efficient ways to prevent HIV and STIs is to get tested frequently. Consistent testing is the only way to confirm whether or not you have an STI and is the first step in treating it. Although there’s a lot to stigma attributed to STIs, we at Freddie like to think of them as regular infections (they just happen to be transmitted through sex).

HIV testing is done through collecting blood and testing it; there are two main tests available in Canada: standard and rapid HIV tests. Most people get a standard HIV test, where blood is drawn from the vein in your arm and sent to a laboratory. You can access free HIV tests in Canada from your family doctor, walk-in clinic, or sexual health clinic. It can take up to two weeks to receive your results.

Rapid testing is a quicker option that gives you your results within a few minutes after doing the test. Rapid tests are considered screening tests, which means that you’d need a confirmatory test to confirm any positive results. This option is more easily available in some regions than in others and can usually be accessed in special sexual health clinics and service providers. Today, some community-based organizations can even send you a rapid HIV test directly to your home.

Are there any differences in accessibility for HIV tests?

Unfortunately, rapid HIV tests can be challenging to access depending on your region. Luckily, new programs by some community-based organizations offer free Rapid HIV self-testing.

Laboratory testing is more easily and equitably accessed across different regions, although it may be challenging to find inclusive and confidential providers in more remote locations. HIV testing can usually be accessed in STI clinics, as well as through family doctors.

How accurate are the tests for HIV?

There are different types of technologies used in Canada to detect HIV in the body. These tests can vary in how they detect HIV, their window period, and result mechanism.

Laboratory Testing

The most common HIV testing method is laboratory testing, where they draw blood from a person’s vein and send it to a laboratory for analysis. All labs in Canada use a fourth-generation test to screen blood samples. If a test comes back positive for HIV, another test is done to confirm the HIV-positive status.

Usually, it can take up to one or two weeks to receive the results from a laboratory HIV test. In Canada, third- and fourth-generation tests have a sensitivity of up to 99.9%, meaning that the test will be falsely negative, or miss a positive result, only 1 in 1,000 times.

Rapid Testing

Rapid HIV testing requires a drop of blood from a finger prick to perform the test. Point of Care testing is when a Rapid HIV test is performed by a healthcare provider whereas self-testing allows somebody to test for HIV themselves.There is only one Rapid HIV test approved for use in Canada - INSTI HIV-1/HIV-2 Antibody Test. Results can be provided within minutes. 

Generally, rapid testing has a sensitivity of 99.5/99.6%. This means they might miss a few more diagnoses than the lab-based tests discussed above and is why we prefer the lab-based tests when we have access to it. When a Rapid HIV test indicates a positive result, a blood sample may be sent to a laboratory to confirm the presence of HIV.  

Testing window for HIV

The HIV testing timeline (also called window period) refers to the time it takes for a new HIV infection to show on HIV tests. The window period for HIV is between two weeks and three months, it varies from person to person and the type of test used.

If somebody had a recent exposure, and is within the HIV window period, HIV tests may come back negative despite the existence of an HIV infection. This happens because the virus has not made enough copies or the body has not yet started producing the antibodies that ‘show’ an HIV infection is present.

Laboratory tests can detect HIV as early as 2 weeks after exposure with a window period of 2 to 12 weeks. It can detect HIV in 50% of people by day 18 and in 99% of people by day 44. Whereas rapid HIV screening tests have a window period between 3 and 12 weeks. They have a 50% sensitivity at day 22 and 99% at week 12.


How urgent is treatment for HIV?

The earlier somebody starts treatment for HIV, the less negative impacts on your body the virus will cause. It’s important to ensure treatment is in place as soon as possible after a diagnosis. Starting HIV treatment right away is paramount when one of the following conditions is present: pregnancy, early HIV infection, and most AIDS-defining conditions.

What happens if I don’t get treated?

If you do not get treated for HIV, your viral load will progressively increase, and your immune system function will progressively decrease. The speed at which that can happen varies widely from person to person. Without treatment, somebody can develop AIDS, which indicates a compromised immune-system and can cause cancers and life-threatening infection.

Can I have sex if I’ve been exposed to HIV?

If you believe you’ve been exposed to HIV or are presenting with symptoms of an acute HIV infection (swollen lymph glands, mouth ulcers, rash, fever, chills, headaches) it’s best to avoid having sex until you’ve been able to get an HIV test. When getting tested, ensure that you’ve considering the window period before resuming sex. Sometimes this requires more than one test. We would also highly recommend a conversation with a healthcare provider.

How long do I have to wait after being treated for HIV to have sex?

HIV treatment not only ensures that somebody can live a normal and healthy life, but it also prevents that person from transmitting HIV to their partners sexually. HIV treatment can reduce the amount of virus in the blood and other bodily fluids to such low levels that we refer to it as undetectable. In order to become and remain undetectable, somebody living with HIV needs to take HIV treatment as prescribed by a healthcare provider and monitor their viral load.

For most people, it takes about three to six months of treatment for the amount of virus in their blood to become undetectable on consecutive tests.

What alternatives can I take if I still want to be sexually active?

If you still want to be sexually active with detectable HIV levels, it’s important to take strategies to lower your risk of transmission. Hand jobs, fingering, and oral sex all present lower risks of HIV transmission than penetrative sex. It would also be important to disclose your status, based on your sexual behaviours.

Disclose your HIV test results to current & previous partners

When an HIV diagnosis takes place, it’s important to let any previous sex or drug use partners know that they should get tested. Ensuring people who were possibly exposed get tested for HIV is a very efficient way to detect, treat, and prevent HIV infections.

If you’re uncomfortable reaching out to your previous partners, a public health nurse can support you. When a public health nurses reaches out to partners, no personal information about you will be disclosed.

How do I tell my partner(s)?

If you choose to tell your partner yourself, it’s important that you’re honest and direct. Although these conversations may not be easy, remember that they are necessary and there’s nothing to be embarrassed about.

Reviewed by:
Dr. Caley Shukalek

Caley is passionate about evidence-based, patient-centred care, including telemedicine that can provide high quality care from wherever a patient may choose.

He helped create Alberta's PrEP guidelines and works as a specialist in General Internal Medicine with additional training in sexual health, including HIV and sexually transmitted infections.

He holds an Masters of Public Health from Johns Hopkins University, an MD from the University of Calgary and an MSc from the University of Alberta.