Health Professionals Resources : PrEP FAQ (ASHM)
PrEP: ASHM answers your Frequently Asked Questions
What is HIV PrEP?
Pre-Exposure Prophylaxis (PrEP) is a medication used to HIV prevention in people who do not have HIV to reduce their risk of becoming infected with HIV. It is recommended that PrEP is taken every day to minimise the risk of HIV.
What is the drug that is used for PrEP?
PrEP contains two antiretroviral medicines, tenofovir ‘TDF’ and emtricitabine also known as ‘FTC’ (in combination known as ‘TDF/FTC’). You may know this medicine by a brand name ‘Truvada’, however there are generic forms of this co-formulated medicine containing the same active ingredients. Truvada in combination with other medicines has been used to treat people living with HIV since August 2004.
How effective is PrEP at preventing HIV infection?
Current evidence shows that regular use of TDF/FTC for HIV PrEP by men who have sex with men provides the highest level of protection when compared to other HIV prevention strategies. In some of the early clinical trials PrEP was not highly effective at preventing HIV infection. For example in the first placebo-controlled study of gay men, PrEP only reduced HIV infection by 44% overall. However, when they looked at the individuals in this study who took PrEP every day, they saw a 99% reduction in HIV infections. In a more recent study where every study participant received PrEP, they saw a reduction in HIV infections of 86%. PrEP reduced HIV infection by 70% in studies of heterosexuals and by about 50% in people who inject drugs. The reason why PrEP’s ability to prevent HIV infection varies quite a lot between these studies is mostly related to how well people in the studies were able to take (or adhere to) the study PrEP medication. In gay men and heterosexuals there is evidence that taking the PrEP tablets every day reduces HIV infection by 99%. Taking it only a few days weekly, or not at all will increase the risk of HIV infection. It is important to note that people who participated in these PrEP clinical trials were also using other HIV prevention strategies as much as possible, including using condoms and having regular tests for sexually transmitted infections and HIV.
Who will benefit from PrEP?
PrEP will benefit men who have sex with men, transgender people, heterosexuals and people who inject drugs who are at risk of HIV infection. Broadly, PrEP is an HIV prevention option that may be considered by anyone who is at high risk of acquiring HIV.
Is generic PrEP safe and effective as TRUVADA®?
Yes. The generic PrEP that we are using is safe and has been approved by the World Health Organisation (WHO), the Federal Drug Administration (FDA) in the United States and is used in the US PEPFAR program for treatment of people with HIV infection. Generics have the same bioequivalence as Truvada and were registered by the Therapeutic Goods Administration for use to treat and prevent HIV infection.
Are there any side effects?
Up to 20% of people starting PrEP may experience mild side-effects such as nausea, headaches and diarrhoea. If this occurs, symptoms mostly disappear after the first 4-12 weeks. A small number of people have experienced more severe side effects.
Are there any guidelines or resources that could help me to find out more about prescribing PrEP?
Yes, the ASHM PrEP Clinical Guidelines (published via the JVE in 2017) were used to inform the PBAC decision to recommend PrEP be listed on the PBS. ASHM have also produced a handy Decision Making Tool to help guide you through the PrEP prescribing pathway.
Is PrEP available in other ways in Australia?
Yes. You can access PrEP through personal importation. This is an option for people who are ineligible for Medicare and unable to access PrEP through the PBS. The cost of personal importation per month is around the same as for a general patient PBS co-payment (approx. $40 per month).
What if someone comes to see me for PrEP who is already enrolled on a PrEP access trial?
All participants enrolled in PrEP access trials will transition to the PBS – although these timelines are different for each State. There will be very few changes when PrEP shifts to the PBS, patients will need to come back for monitoring every three months.
Keep checking in to this page for information about trial dates as we get them.
Will local pharmacies dispense PrEP or will patients need to go to a hospital pharmacy?
All pharmacies will be able to dispense PrEP, however some pharmacies may need to order the medication which can take a few days.
I am a GP and have been prescribing PrEP for three years (private and importing) for my patients. I have about 30 patients on PrEP. If a HIV virus mutates and is resistant to tenofovir or emtricitabine, does that mean PrEP won’t prevent transmission of this virus? How likely is this to happen? Can we do anything to stop it?
Answered by Vincent Cornelisse, Sexual Health Physician Prahran Market Clinic & Melbourne Sexual Health Centre and ASHM PrEP Clinical Advisor
Your question is a good one, and a difficult one to answer. If a PrEP user is exposed to a HIV virus that is resistant to both tenofovir and emtricitabine, then PrEP is unlikely to reduce their risk (at least, the PrEP that is currently available). There have now been a couple of cases internationally where men with good PrEP adherence (as indicated by tenofovir levels in their blood) have seroconverted after sexual contact with someone who had HIV with antiretroviral resistance. Both of these cases occurred in North America. After diagnosis it was shown that their HIV virus was resistant to not only TDF/FTC, but they also carried mutations that conferred resistance to other classes of antiretrovirals, which must mean that their HIV virus already had these mutations when they acquired the virus, because TDF/FTC exposure cannot induce resistance to antiretroviral agents in other classes.
So, PrEP is not 100% effective, but I guess there’s a few things to keep in mind:
- Transmitted resistance is uncommon, and less common in Australia than in the USA. This is probably a reflection of differences in our healthcare systems. As in, Australia has a version of universal healthcare, so it’s relatively easy for people to get a HIV test, and similarly it is fairly easy to access treatment once diagnosed. This can be more difficult in the USA, particularly if people are unemployed (and hence uninsured). I’m speculating here, but I would think that by having easy healthcare access, we in Australia have fewer people whose HIV treatment is failing, and hence fewer people who carry HIV resistance mutations.
- Thousands of MSM are using PrEP. We know of less than a handful of people who have seroconverted whilst on PrEP and whilst having good adherence. I guess what I’m saying is that we need to put this into perspective.
Where does that leave us? I don’t think we can say that PrEP is 100% effective, but other than abstinence from sex there is no HIV prevention strategy that is 100% effective, and PrEP is the most effective HIV prevention strategy we have available. I inform my patients of this, and I discuss with them the importance of keeping condoms in their sexual health prevention toolbox. All we can really do is give people accurate information, and then they can decide what HIV prevention strategies are suitable for their situation.