Canadian research suggests that rolling out Truvada (tenofovir/emtricitabine) as pre-exposure prophylaxis (PrEP) to prevent HIV would save money in the long run. The researchers assumed that the lifetime cost for someone who contracts HIV at age 30 and takes the cheapest regimen would be 1.44 million Canadian dollars (about $1.2 million). Factoring in the 2010 iPrEx study estimate that 52 people would need to take PrEP for one year to prevent one infection, they calculated that PrEP saves CA$814,000 (about $677,400) for each infection averted. If treatment costs fall in the future, PrEP could lose its cost-saving status, but it likely would not if the effectiveness of real-world PrEP use significantly exceeds iPrEx’s population-level HIV risk reduction rate of 44 percent. Taking PrEP on an as-needed basis instead of daily, as in the recent IPERGAY trial (which showed an 86 percent overall effectiveness), could reduce the prevention cost as well.