Truvada taken as an HIV preventative is shown to be an incredibly effective way of stopping the spread of HIV. In 2014 the iPrEx OLE study showed that when taken between 3 and 7 times a week, seroconversions were close to 0%. A new study from Britain called PROUD has come out with some slightly different numbers, but numbers that are still encouraging: 86% of the men studied were protected by a Truvada regimen. Not as great as 99.99%, but still a good notch better than the 76% offered by condoms alone. Naturally, the best results are achieved when multiple prevention tools are used in tandem, and condoms plus PrEP make for an even more solid barrier.

Here's where things get interesting: the IPERGAY study out of Canada and France showed that the 86% efficacy can be achieved even when taken "on-demand", which is defined here as once 2 to 24 hours prior to sex and once after.

These "on-demand" results could completely change everything, as both cost and potential side effects are some of the biggest concerns voiced against Truvada. The cost per pill is still somewhere in the neighborhood of $50, unsubsidized, so it's still not within everyone's reach, but being able to drop $100 without insurance for a preventative measure broadens the reach far beyond the standard of uninsured or underinsured people going without because they can't pony up $3k+ for a month's supply. Also, while the side-effects of the pill are minimal and typically reversible, just two pills could provide the needed benefit without being enough to make most of those side effects kick in.

Stand by for Michael Weinstein to rehash his accusation that Truvada is a party drug…though if Truvada is a party drug, does that make condoms party balloons?