HIV Prevention

HIV Transmission

HIV can only be transmitted through certain fluids: blood, semen, rectal fluid, vaginal fluid or breast milk gets into the body of another person. HIV is most commonly passed through sex. sharing needles. or other drug use equipment.

What is PrEP?

HIV pre-exposure prophylaxis (PrEP) is a highly effective HIV prevention strategy that involves an HIV-negative person taking HIV medications on an ongoing basis to reduce the risk of HIV infection. When PrEP is taken as prescribed, HIV transmission is very rare.

There is the Hamilton PREP Clinic where you can receive assistance in getting PrEP. PrEP does not protect against other STIs, so it is recommended to be used with a condom.

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How well does daily PrEP work?

PrEP using TDF + FTC

A large body of evidence shows that daily PrEP (using TDF + FTC) is highly effective at reducing the risk of HIV acquisition when used consistently and as prescribed. Daily PrEP was initially proven effective on the basis of evidence from randomized controlled trials (RCTs) conducted in gbMSM, in transgender women, and in heterosexual men and women. In addition, limited evidence from one RCT found that daily PrEP (with TDF alone), is effective at reducing the risk of HIV transmission among people who inject drugs when it is used consistently and correctly.

PrEP using TAF + FTC

Data on the effectiveness and safety of TAF + FTC as PrEP come from only one randomized controlled trial (RCT) with gbMSM and a small number of transgender women. Participants were randomly assigned to take either daily TAF + FTC or daily TDF + FTC. This trial found the newer version of PrEP (TAF + FTC) to be “non-inferior” to the original (TDF + FTC) – meaning it works just as well, in the population studied (gbMSM and transgender women). The efficacy and safety of the TAF + FTC PrEP formulation has not been studied for preventing HIV among people who have vaginal (or frontal) sex or among people who use drugs.

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What is on-demand PrEP?

On-demand (or intermittent) PrEP means taking pills only on days before and after having sex. It is sometimes referred to as 2-1-1 dosing. The Canadian PrEP guideline states that on-demand PrEP can be considered as an alternative form of PrEP for gbMSM only. This could be a good option for men who know in advance when they will have sex. There is no evidence to support the use of on-demand PrEP by other populations.

This involves taking:

• 2 pills between 2 and 24 hours before sex
• 1 pill 24 hours after the first dose
• 1 pill another 24 hours later

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What is PEP?

Post-exposure prophylaxis (PEP) is an effective strategy for HIV prevention that involves an HIV-negative person taking HIV medications within 72 hours of potential exposure to reduce the risk of HIV infection. PEP is commonly accessed through an emergency room visit. If you think you need PEP go to a hospital or emergency room straight away.

When taken as prescribed for 28 days, PEP is very effective at preventing HIV infection.

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PEP does not prevent 100% of HIV infections, but is quite effective.

Observational research suggests that PEP can reduce the risk of getting HIV by more than 80%, which means some people in the studies acquired HIV despite taking PEP. Although some of these people reported high adherence to PEP and no further exposures to HIV, many HIV transmissions among people taking PEP occurred due to low adherence (not taking PEP every day for 28 days) and/or ongoing exposures to HIV. Effectiveness is likely much higher than 80% if PEP is used consistently and as prescribed.

This would include:

• Obtaining PEP from a healthcare provider.
• Taking the medications every day for 28 days. High adherence to the full month-long course of PEP is important for maximizing effectiveness.
• Starting PEP as soon as possible after a potential exposure to HIV. The sooner PEP is started after exposure to HIV the more likely it is to work.
• Taking extra precautions to reduce the risk of being exposed to HIV again while taking PEP. The use of PEP is meant to reduce the risk from a single exposure to HIV and should only be used for emergencies.

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Undetectable is Untransmittable

U=U means that people with HIV who achieve and maintain an undetectable viral load (the amount of HIV in the blood) by taking antiretroviral therapy (ART) daily as prescribed cannot sexually transmit the virus to others.

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