Its a relatively new drug which is why it hasn't been mentioned on older programs.
Relatively new? What are you, in 2010? Noā¦ Something like Triumeq is relatively new. Truvada (aka PrEP) didn't come out to the market until early 2009. Just to be technically correct. 
It didn't reach the "mass" market until late 2010 after patients like me had undergone all the studies and such in an effort to get away from harsher drugs like Sustiva.
But they are scared that it is not 100% secure if someone forget to take prep for one or a few days.
Even if it is taken on time every day, it is still not a guarantee, especially for a "die hard gangbanger" as there is now a strain of HIV that has popped up that is actually resistant to Truvada. In the case o the "die hard gangbanger" (which I fall into the category of), Truvada is even less of a guarantee because of that nature of the increased risk of being introduced to that one particular strain. Also, take into account the number of people with HIV who are on HAART already and maintain an undetectable viral load, which is statistically a safer bet than even a condom. On that noteā¦ One day of missing your Truvada won't necessarily do anything, as long as it has been at LEAST a month since you missed your last dose (although the more time you have between missed doses the better, and ideally zero is the target number of missed doses).
Also, I can tell you from first hand experience that the long-term effects of Truvada are questionably worth it, depending on a few factors. In my case, they unfortunately were worth it, as it kept me alive for a number of years, however I still pay for that decision to stay on it for as long as I was. Simply put, it irritates your GI tract, which can cause various things like random nausea and a sudden urge to vomit (although not frequently, just inconveniently and annoyingly, and you're fine after it happens), and my favouriteā¦. It makes for a rather "shitty" situation quite easily. Originally, when I started with Truvada, it was a constant battle with incontinence. The only problem is that when it feels like you're literally pissing out your ass, there's not much you can do to keep it on the down-low, especially when you're say, in the middle of a crowded Canadian Tire store just before Christmas when suddenly, without any warning, "shit happens" (pun intended). Even now, a couple of years free from Truvada, and I still have that side effect quite easily, depending on what I eat. Thankfully, it's not as bad now as it used to be, but it's still a royal pain in the ass. Speaking of which, Truvada has caused me to have another rather unattractive quirk... I can't stop fluffing up a storm in my sleep, and according to a couple of my ex's, it's pretty wicked. I don't mind it because I sleep like a baby right through it, but when you're in a tiny little trailer and you're trying to get near and dear to someone who happens to be a light sleeper, things can get real fun when they threaten to go to bed with a gas mask because of it.... Just sayin'
These are the things that they do NOT tell you in the textbooks folks... I had to learn this the hard way as one of the first experiment patients to be put on this because my other option was Sustiva, which scared the living shit out of me. You either get Lucy in the sky with diamonds dreams, or in my case, you get to go to bed knowing that every night is a night at 1428 Elm Street on Sustiva. Also, having seen what my ex went through with being on Sustiva for 13 years and the way it has fried his brain over time, I didn't have much of a choice but to become one of the first trial patients... I'll be the first to admit, things are nowhere near as bad now as they were even when I was diagnosed, but even being diagnosed at such a key turning point in the science, there are prices we've all had to pay in exchange for our lives.
Just a friendly reality check.
