One of the big concerns for European governments considering whether and how to make Truvada available as pre-exposure prophylaxis for HIV (PrEP) is the cost. The medication itself is expensive, and it also requires on-going support from medical providers. In many European countries these costs will be borne largely or entirely by state-funded health systems.
Studies have consistently found that to be cost-effective PrEP, needs to be used by those at the highest risk of acquiring HIV. How high? The World Health Organization suggests that giving PrEP to people in groups with an incidence of 3% per year would be cost effective, while estimates in the UK suggest a minimum incidence of 5%.
Although gay and bisexual men generally are at elevated risk of infection, not every gay or bisexual man is at equally significant risk of acquiring HIV. In the US, the Centers for Disease Control and Prevention recently estimated that about 1 in 4 sexually active HIV-negative gay and bisexual men would benefit from PrEP.
One of the most important results of the PROUD trial in the UK was that the men in the study who were not using PrEP had an extremely high incidence of 9%. The French IPERGAY trial also found that men in the control group had a high rate of incidence (6.75%). This meant not only that Truvada as PrEP was (yet again) confirmed to be extremely effective at preventing HIV, but, crucially, that both studies had been extremely successful at recruiting men at very high risk of acquiring HIV.
But these studies were relatively small, and it’s not clear that simply applying the same criteria used for participation in the studies on a wider scale will be as effective at targeting the right people, or what criteria will be appropriate in other countries. While people at the highest risk of infection have been shown to be the most motivated to seek out and use PrEP, cost-conscious health systems want to have an idea of where to draw the line for eligibility so that those at low risk of infection do not use resources that could benefit others more.
So how do health authorities make sure they can reach those at higher risk, that the people who most need PrEP get it first?