it's farley nirly new. they approved a drug called truvada, but research showed that hiv negative people can take this and prevents hiv from becoming an infection in their body if they're exposed. and it actually works extraordinarily well, if the person actually takes the pill. so much like women have a pill to prevent pregnancy, if they don't take that pill, it doesn't work, right? so if you're adherent to truvada, the data says it's 95% to 100% effective. that's an extraordinary breakthrough. condoms have shown 75% to 80% effectiveness. >> prior to this, the only other method for prevention has been condoms and and stinance? >> correct. and we've had to rely on human behavior for 30-some years, and that's a really hard thing to change. to have a medical intervention is keeping people from being at risk is amazing. >> we'll talk more about that and about the walk. stay with us. >>> welcome back. we're talking about the aids walk coming up on october 25th here in the nation's capital, the walk to end hiv.