PrEP’s effectiveness at preventing HIV infection is directly linked to how adherent you are (or how faithful you are in taking PrEP every day as prescribed). Only a handful of PrEP users demonstrated to be taking PrEP daily as prescribed have ever been infected with HIV. Most of those cases were likely due to an extremely rare scenario where the strain of HIV they were infected with was resistant to the two medications present in PrEP (More on that here, here, and here).

However, the more doses you miss, the less benefit PrEP provides. For example, in the iPrEX OLE trial there was a significant decrease in HIV risk reduction amongst those who only took 2-3 pills per week when compared to those who took four or more pills per week. The effectiveness decreased even further for those who took less than 2 pills per week.

​Fortunately, both demonstration projects and real-word PrEP data have demonstrated that those who commit to taking PrEP demonstrate a high level of adherence.  Additionally, specialized health clinics with large numbers of patients taking PrEP have reported no HIV infections amongst their PrEP patients despite a reasonably high rate of other STIs, reaffirming both the effectiveness of PrEP as an HIV prevention tool and the likely high rate of adherence demonstrated by those taking PrEP.

​If you find that you experience challenges taking PrEP daily as prescribed, make sure you speak to your healthcare provider. They can help you develop strategies to make taking PrEP daily easier for you. Furthermore, if a high level of PrEP adherence is still challenging for you, you may want to speak to your healthcare provider about the possibility of taking PrEP intermittently (as discussed briefly below). Otherwise, if PrEP adherence is not possible for you, it might be best to look at other effective HIV prevention strategies.

​Remember, if you’re on PrEP and don’t take it as prescribed, it won’t be as effective as it can be. This might provide you with a false sense of security. If that’s the case, it’s probably a good idea for you to discuss other HIV prevention strategies with your healthcare provider, including the use of barrier methods such as condoms, ensuring that both you and your partners test regularly for HIV and STIs, and to ensure that HIV-positive partners are on treatment and have attained an undetectable viral load.

Finally, some research has demonstrated that PrEP can also be effective at preventing HIV infection when taken intermittently or “on-demand.” Although some individuals are choosing to take PrEP this way, it is important that both you and your physician understand the “ins and outs” of intermittent PrEP use. Most medical guidelines still support the daily use of PrEP, recognizing that more research may be required to fully understand the various nuances of intermittent PrEP use. So, although we encourage taking PrEP daily as prescribed, if you and your healthcare provider wish to look closer at intermittent PrEP options, you can review the guidance provided in the Canadian PrEP guidelines.

Ongoing Monitoring & Follow-Up

In addition to things you can do personally to make sure your journey with PrEP is healthy and provides you with maximum benefit, there are a few things your healthcare provider will want to do as well.

Firstly, you and your provider should continue to have ongoing discussions about your sexual health – particularly when your sexual health circumstances change (i.e. you enter or exit a monogamous sexual relationship, the HIV status of your sexual partner(s) changes, or your use of other HIV prevention methods increase or decrease). This is important to make sure that PrEP is still an HIV prevention option that makes sense for you.​Additionally, there are other sexually transmitted and blood borne infections (STBBIs) that can negatively impact your health besides HIV – some of which, like syphilis, can even lead to severe neurological impairment or death if undiagnosed. By having ongoing conversations about your sexual health circumstances and HIV/STBBI prevention practices, your healthcare provider can ensure you have the knowledge and tools necessary to ensure optimal sexual health.

Besides ongoing sexual health counselling, your healthcare provider should run a series of tests on you when you start PrEP and at varying points while on PrEP (30 days after you start, every three months, and yearly) to make sure you remain HIV-negative, STI free, and that the medication isn’t having any negative effects on your health.
In many cases, your healthcare provider will require you to complete recommended screenings before renewing your prescription. Although this might seem like an inconvenience, it is a small price to pay to access PrEP and maintain optimal sexual health! For a list of recommended screenings and related frequencies, click here.

Stopping PrEP

There might come a time when you – maybe on your own or with the guidance of your healthcare provider – determine that PrEP isn’t right for you anymore. Before stopping PrEP, make sure you consider a few things:​

• PrEP isn’t always easy to access. If it initially took you a while to obtain a prescription and subsequent coverage, if you decide to go back on PrEP again in the future, you might have to repeat some or all of that process. Like most major life decisions, the decision to stop PrEP shouldn’t be made on a whim.
• Before you stop PrEP, take some time to think about whether or not the circumstances related to deciding to stop taking PrEP will remain static for a while, or if they could change in a month or two leading you to consider starting PrEP again. If things are prone to fast change, perhaps wait a little while before making a decision to stop.
• If you haven’t made the decision to stop PrEP in consultation with a healthcare provider, you should make sure you speak with your PrEP prescriber before choosing to stop. They could support you through that decision-making process and if you do decide to stop taking PrEP they can help you determine other HIV prevention strategies for moving forward.
• The Canadian PrEP/nPEP Guidelines recommend continuing PrEP for up to  28 days after your last potential exposure to HIV.

PrEP isn’t for everybody. Some people aren’t great candidates for PrEP to begin with. Some people might only benefit from PrEP for a short period of their life, stopping when circumstances change. And others would likely benefit from PrEP for a longer period – perhaps for their entire life. There’s nothing wrong with reviewing your sexual health practices and determining that what worked for you a month or year ago concerning HIV prevention is no longer the best option for you today. Just make sure that before stopping PrEP you take some time to look at other HIV prevention options to use in PrEP’s absence.