Post-Exposure Prophylaxis in the Era of Pre-Exposure Prophylaxis

M Atim, N Girometti; I Hyndman; A McOwan; G Whitlock


HIV Medicine. 2020;21(10):668-670. 

Objectives: 56 Dean Street (56DS), a sexual health clinic in London, provides a quarter of England's HIV post-exposure prophylaxis following sexual exposure (PEPSE). Since the limited introduction of pre-exposure prophylaxis (PrEP) in 2015, PEPSE demand has fallen.

Methods: We performed a case-note review of individuals who received PEPSE at 56DS in August 2018.

Results: Two hundred and forty three PEPSE were given; 97% (236) fitted recommended indications according to UK national guidance. Twenty-eight (12%) had documented prior PrEP use; the most common reason for not taking PrEP was lack of supply (15/28; 54%). Up to 1st April 2020, of 215 who had not previously used PrEP, 106 (49%) re-attended 56DS for PrEP initiation.

Conclusions: At 56DS, PEPSE is appropriately given for high-risk HIV exposures. For those who use PrEP, It is important to support their adherence and ensure adequate supply. As PrEP uptake increases, the need for PEPSE may decrease.

In the UK, HIV post-exposure prophylaxis (PEP) following sexual exposure (PEPSE) is available free of charge in the NHS through A&E departments/emergency rooms and sexual health clinics. 56 Dean Street (56DS), a combined sexual health and HIV clinic in Soho, central London, provides walk-in assessment for and provision of PEPSE in accordance with the British Association of Sexual Health and HIV (BASHH) PEPSE guidance.[1] Where PEPSE is indicated, a specific PEP proforma is completed in the clinic electronic patient record system and a 28-day course of raltegravir and co-formulated emtricitabine-tenofovir disoproxil fumarate is dispensed and individuals are advised to re-attend as a walk-in appointment for repeat HIV testing following its completion. In 2018, 56DS provided 2998 of England's 12 250 PEPSE prescriptions, accounting for a quarter of the PEP given nationally.[2]

Whereas men who have sex with men (MSM) account for 58% attendances at 56DS, the majority of PEPSE recipients at our centre are MSM (98% in 2013)[3,4] and they have historically had a high rate of subsequent HIV infection which has also been seen in other urban settings.[5,6] Therefore, at 56DS we have sought to champion combination HIV prevention including treatment-as-prevention, rapid initiation of antiretroviral therapy in individuals newly diagnosed with HIV and promotion of pre-exposure prophylaxis (PrEP) during the clinic attendance and by 'Dean Street PRIME', a web-based package of tailored advice and information around HIV risk reduction dedicated to individuals at higher risk of HIV acquisition; where no reduction strategies are being used, we encourage frequent HIV testing.[7] We believe this combination prevention approach has led to the continued fall in HIV incidence seen at 56DS from 299 cases in 2016 to 141 cases in 2018.[8,9]

Since the limited availability of oral HIV PrEP at 56DS from September 2015, there has been some debate about its impact on PEPSE. Our own data suggest that as PrEP uptake has increased, PEPSE demand has fallen from around 330 prescriptions per month in 2017 to 250 in 2018, with more individuals using PrEP mitigating the need for PEPSE.[10,11] Elsewhere, albeit in smaller numbers, PEPSE demand has increased since PrEP introduction, suggesting increased awareness around all forms of HIV prevention.[12] At present, there is limited access to PrEP in England through clinical trials, online purchase (predominantly through dedicated websites) or 56DS's own PrEPShop.[7] However, it is still unclear if individuals who recurrently use PEPSE are actively choosing PEPSE as a risk reduction strategy as opposed to requesting PEPSE following the failure of other strategies (such as condom break, poor PrEP use or suboptimal access) and which biomedical approach (PEP or on-demand PrEP) is most suitable for individuals with infrequent HIV risk exposure.[13]

The purpose of this review is to describe the characteristics of PEPSE recipients at 56DS and their subsequent PrEP initiation.

We performed a retrospective case-note review of individuals who received PEPSE at 56DS between 1 and 31 August 2018 inclusive. Data were inputed into Excel including date of birth, date of PEPSE consultation, where PEP was initiated, time of exposure, gender of recipient, nature of exposure (the highest risk exposure, number of individuals to which the individual was exposed, recreational drug/'chems' use during the risk). Case notes were reviewed from first PEPSE until 1 April 2020 for the most recent HIV test and PrEP use/initiation.

In August 2018, 243 individuals received PEPSE at 56DS; 242 were male and one was female (Table 1). Their median age was 32 years (interquartile range, 28–38 years). PEPSE was most likely to be given on Monday with fewer prescriptions later in the week; 56DS is closed on Sundays. The highest risk exposure was unprotected receptive anal intercourse (213, 88%) followed by unprotected insertive anal intercourse (25, 10%). The majority of exposures (213, 88%) were with individuals of unknown HIV status; 30% (74) of exposures involved more than one source individual (group sex). Chemsex during exposure was reported in 21% (52).

Twenty-eight (12%) had documented prior PrEP use, with the most common reason given for not taking PrEP as lack of supply (15/28, 54%). In accordance with national auditable outcomes, 97% (236) of PEPSE prescriptions fitted the recommended indications and 99.6% (242) of PEPSE was given within 72 h of the risk exposure. All recipients received HIV testing at PEPSE initiation. Repeat HIV testing was performed in 125 (51%) within 12 weeks of PEPSE, and up to 1 April 2020, 198 (81%) had re-attended 56DS for a repeat HIV test. One individual tested positive for HIV 12 months after receiving PEPSE, having completed the 28-day PEPSE course and having tested negative for HIV 9 weeks following PEPSE completion.

Two hundred and fifteen of the study participants had not used PrEP prior to their PEPSE consultation in August 2018, of whom 106 (49%) subsequently re-attended 56DS for PrEP initiation.

Our data suggest that in the era of PrEP, PEPSE continues to be prescribed appropriately for high-risk HIV exposures. The characteristics of PEPSE users at 56DS in August 2018 are similar to PEPSE users 5 years earlier, as shown by a similar analysis performed at our service in 2013.[3] In both analyses, more than 95% of PEPSE prescriptions were given within BASHH recommended guidance.[1]

Even in the English setting of limited PrEP availability, in the 20 months following the receipt of PEPSE at 56DS, at least half of those individuals have started taking PrEP. This may be an underestimate as not all have re-attended our service in the intervening period. Assuming PrEP is taken correctly in this cohort, this should result in fewer PEPSE prescriptions and a continued low HIV incidence. It will be interesting to see how the proposed rollout of PrEP in England from the autumn of 2020 will affect the amount of PEPSE prescribed.[14]

It is notable that 12% of PEPSE prescriptions were given where individuals had already been in receipt of PrEP, most commonly where supply had run out. In order to monitor this, we have since changed our PEP proforma to specifically ask if PrEP has been used in the previous 3 months and, if not, the reason why this was not used.

With PrEP finally due to be available free of charge in England from the NHS outside a trial by the autumn of 2020, this project has implications for the planning of risk reduction services within English sexual health clinics, given that half of our PEPSE recipients subsequently start PrEP to manage their HIV risk. We feel that it is important to offer PrEP for those at high risk of acquiring HIV in line with existing national PEPSE guidance.[1] For those already using PrEP, it is also important to support their adherence and ensure adequate supply. Clinics should be aware that, as PrEP uptake increases, the need for PEP may decrease.