Cost utility analysis of HIV pre exposure prophylaxis among men who have sex with men in Israel.

Background: Between 2011 and 2015, Men who have sex with men (MSM) accounted for nearly half of new HIV cases among men in Israel. This study carries out a cost-utility analysis of PrEP (HIV Pre Exposure Prophylaxis), an antiretroviral medication that can protect against the acquisition of HIV infection, whose incidence rate in Israel is around 1.74 per 1000 MSM.

Method: Epidemiological, demographic, health service utilisation and economic data were integrated into a spread-sheet model in order to calculate the cost per averted disability-adjusted life year (DALY) of the intervention from a societal perspective, in mid-2018 US$ using a 3% discount rate. Cost utility analyses were performed for both types of PrEP delivery (continuous regimen and on-demand), together with sensitivity analyses on numbers of condom users who take up PrEP (baseline 25%) and subsequently abandon condom use (baseline 75%), PrEP efficacy (baseline 86%), PrEP prices and monitoring costs.

Results: Around 21.3% of MSM are high risk (as defined by having unprotected anal intercourse). Offering PrEP to this group would have a ten year net cost of around 1563 million USD, preventing 493 persons from becoming HIV-positive, averting around 1616 DALYs at a cost per averted DALY of around 967,744 USD. This will render the intervention to be not cost-effective. PrEP drug prices would have to fall dramatically (by 90.7%) for the intervention to become cost-effective (i.e. having a cost per averted DALY less than thrice GNP per capita) in Israel. PrEP remains not cost-effective (at 475,673 USD per averted DALY) even if intervention costs were reduced by using an "on demand" instead of a daily schedule. Even if there were no changes in condom use, the resultant 411,694 USD cost-utility ratio is still not cost-effective.

Conclusions: Despite PrEPs high effectiveness against HIV, PrEP was found not to be cost-effective in the Israeli context because of a combination of relatively low HIV incidence, high PrEP costs, with a likelyhood that some low-risk MSM (ie: who use condoms) may well begin taking PrEP and as a consequence many of these will abandon condom use. Therefore, ways of minimizing these last two phenomena need to be found.