Truvada (PrEP) is used to prevent HIV (Photo: NIAID | Commons)
This week, the World Health Organisation (WHO) launched new international recommendations on the use of event-driven PrEP (ED-PrEP) (or as it is now increasingly being called – 2+1+1 dosing).
The guidance calls for ED-PrEP to be included in national guidelines and protocols, and to be offered to men having sex with men (MSM) as an option, in addition to daily PrEP.
Citing data from available trials and open-label extensions of trials, including the recent evidence from a two-year demonstration study in Amsterdam, WHO’s report states that ED-PrEP is safe and highly effective at preventing HIV during sex between men. It is as effective as daily PrEP use, the guidance says.
Evidence about the efficacy of event-driven dosing has been in existence since the results of the IPERGAY Trial were released in 2014, and event-driven dosing has been offered as an option in England’s IMPACT Trial since October 2017.
Data from a 2018 user survey suggests that about a quarter of UK PrEP users are already using non-daily PrEP.
However, this report is the first time that WHO has unambiguously endorsed non-daily PrEP as an option to prevent HIV during sex between men.
Who needs to daily dose
The report cautions that the evidence only supports this kind of dosing during sex between men.
Until any new evidence emerges to the contrary, WHO recommends daily dosing for cis and trans women, and trans men whose HIV risk is through vaginal/frontal sex.
Daily dosing also remains an option for men who are having sex with other men, with ED-PrEP adding an additional method.
But what is ED-PrEP and who might it be useful for?
If it’s a one-off episode of sex, then there’s no need to take more than those doses. But if sex is continuing, then it’s important to keep taking one pill every 24 hours, and to continue until 48 hours after the last sex happened.
Some people want to use ED-PrEP because they think that their HIV risk doesn’t justify taking a pill on a daily basis. It’s not uncommon for people to use this way of dosing if they have a restricted amount of PrEP and want to ration it out.
And some people want to restrict the amount of the medication that goes into their body, because of concerns about side effects (although the side effects are minimal).
For others, the dosing regime for ED-PrEP seems too complex and they are concerned that they will forget one or more doses. Given the importance of taking the after-sex doses, it’s important to develop ways of remembering to take all of the pills. Some people use apps or phone alarms to remind them when to take their after-sex medication.
ED-PrEP is a good option for people who can pre-plan their sex – they’ll need at least to know at least two hours in advance, so they can double dose. And for those of us who have more spontaneous sex? Daily dosing might be a more reliable
This new guidance from WHO adds endorsement of a further option for using PrEP. With the same conference showing promise of long-acting injectable PrEP, and recent announces about the start of HIV preventative vaccines, the options for preventing HIV are at a new and exciting cross-roads.
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For more information on dosing click here.
Dr Will Nutland is the co-founder of PrEPster. He is also an Honorary Assistant Professor at the London School of Hygiene and Tropical Medicine.