HIV prevention

Updated on:
August 17, 2021

In order to prevent HIV, we must first look at the way HIV can be transmitted. Anyone can get HIV, regardless of age, sex, gender, sexuality, and ethnicity. There are five bodily fluids which have the potential of transmitting the virus:

  • Blood
  • Semen (includes pre-cum)
  • Vaginal fluids
  • Anal fluids
  • Breastmilk

It is only when one of these fluids enters the blood of somebody else that there is a risk of HIV transmission. A transmission can occur through: broken skin, penis opening, vagina, rectum, foreskin. The main ways to pass HIV are through sex and sharing needles.

Which methods are more likely to transmit HIV?

For an HIV transmission to take place, there are three main needed components: a fluid, a route for entrance, and an activity that facilitates entrance. The fluid must contain enough HIV and enter the bloodstream of an HIV-negative person.

The types of sex that have the highest risk for HIV transmission are anal and vaginal sex. Receptive anal sex carries the highest risk of transmission (10 or 20 times higher than insertive anal sex or receptive and insertive vaginal sex). The reason for that is thinner linings in the rectum are more susceptible to tears, which can facilitate the entrance of the virus in the bloodstream.

In terms of vaginal sex, receptive vaginal sex is around two times higher risk than insertive vaginal sex for transmission. When it comes to giving oral sex, there may be some risk of HIV transmission through sores or cuts in the mouth or throat. There’s a very small chance of getting HIV if an HIV-positive person ejaculates in their mouth, and almost no chance if there’s no ejaculation. Receiving oral sex and performing cunnilingus and annalingus are even lower risk. 

It’s important to note that if somebody with HIV is on treatment, and their viral load is suppressed, they cannot transmit HIV to their sexual partners through any form of sex.

Sharing needles can also pose a high risk of HIV transmission, even if the amount of blood cannot be seen since needles provide a direct pathway into the bloodstream. This risk is thought to be reduced if a person is on treatment for their HIV, though data is limited in this area.

Lastly, there’s a 15 - 30% chance of transmission from parent to child during childbirth. HIV treatment can ensure HIV positive parents give birth to HIV negative babies. There is also a 5 - 20% chance of transmission through breastfeeding that is decreased but still possible among those with an undetectable viral load. 

When is HIV contagious?

HIV is contagious at any stage, unless a person is on treatment and maintains a suppressed viral load. In that case, HIV cannot be transmitted through sexual contact.

Is it more contagious at certain times than others? Why?

HIV’s ability to transmit is directly correlated with the amount of virus in the bloodstream. When somebody first contracts HIV, the viral load increases dramatically and the immune system cells decrease, during this time some people may experience flu-like symptoms (this period is called acute HIV seroconversion). At this point, HIV is very contagious as the viral load is high.

After some time, the viral load lowers and stabilizes, and the immune system returns to its previous, normal function. At this point, somebody may present with no symptoms but remain contagious for HIV. If a person living with HIV does not access treatment, the viral load will progressively increase, decreasing immune system function and raising the risk of transmission to others.

So, it’s safe to say that, although HIV is contagious at all of its stages (unless viral load has been suppressed), it’s more contagious when the viral load is higher. Inflammations, sores, tears on the skin, and anything else that can facilitate entrance into the body can also increase the likelihood of HIV transmission.

Does HIV even stop being contagious? Why?

HIV-positive people with access to treatment can achieve a suppressed or undetectable viral load, which makes it impossible for them to transmit HIV to their sexual partners (undetectable = untransmittable; U=U).

Are there cases when it’s not contagious at all?

HIV is not contagious at all through sexual contact with a person who is undetectable - somebody who maintains a suppressed viral load by being on treatment (U=U).

How to prevent HIV

Follow these HIV prevention methods:

Condoms (protecting the user)

Using a condom correctly and consistently helps prevent HIV and STIs. Using lube can help prevent tears which can facilitate the transmission of HIV and STIs.

When using condoms, make sure to use only water or silicone based lubricants. Oil-based lubricants can cause condoms to break meaning there is no barrier and fluids can be exchanged.

Dental dams (protecting the user)

Although there is almost no chance of getting HIV from cunninlingus, and no chance of receiving it, using dental dams can further reduce the likelihood of transmission while eating someone out and can prevent transmission of other STIs.

Proper hygiene (protecting the user)

Cleaning sex toys between each use and using condoms on sex toys can reduce fluid transmission and reduce the chance of transmitting or getting HIV.

HIV prevention pill (protecting the user)

Pre-Exposure Prophylaxis (PrEP) is an HIV prevention medication that is 99% effective when taken everyday, it’s well suited for communities at higher risk of transmission. Post-Exposure Prophylaxis (PEP) can prevent HIV transmission after a potential exposure to HIV. PEP is taken for 28 days and most effective when taken as close to, but for sure within 72 hours of, a possible exposure.

Testing (protecting the user)

According to 2018 data, around 87% of Canadians with HIV were diagnosed, which means that about 13% of HIV-positive people do not know their status. Getting tested for HIV is the only safe way to know if you are positive or not.

Preventing HIV starts with normalizing testing, since treatment for HIV ensures someone can live a health and normal live without being able to pass on the virus sexually.

How do I prevent myself from transmitting HIV?

  • Condoms (protecting the partner)
  • Dental Dams (protecting the partner)
  • Proper Hygiene (protecting the partner)
  • Pill and/or vaccination (protecting the partner)
  • Testing (protecting the partner)

Can you prevent HIV 100% of the time?

Although prevention effectiveness relies on many variables, such as correct and frequent use of condoms, no tears, consistent PrEP adherence, it’s difficult to have 100% control of your risk for HIV.

What is known to maximize your ability to prevent transmission, is called ‘combination prevention’, which is the simultaneous use of different prevention strategies.

This would include: getting tested often for HIV and STIs, speaking to your partners about their testing and STI history, using condoms, using PrEP, accessing harm reduction resources when using injection drugs, using lube to avoid condom and tissue damage, etc. A combined approach to prevention may be the best chance of maximizing your ability to prevent HIV and other STIs.

How do I prevent myself from transmitting HIV?

  • Condoms (protecting the partner)
  • Dental Dams (protecting the partner)
  • Proper Hygiene (protecting the partner)
  • Pill and/or vaccination (protecting the partner)
  • Testing (protecting the partner)

Can you prevent HIV 100% of the time?

Although prevention effectiveness relies on many variables, such as correct and frequent use of condoms, no tears, consistent PrEP adherence, it’s difficult to have 100% control of your risk for HIV.

What is known to maximize your ability to prevent transmission, is called ‘combination prevention’, which is the simultaneous use of different prevention strategies.

This would include: getting tested often for HIV and STIs, speaking to your partners about their testing and STI history, using condoms, considering using PrEP, accessing harm reduction resources when using drugs, using lube to avoid tears, etc. A combined approach to prevention may be the best chance of maximizing your ability to prevent HIV and other STIs.

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.