HIV prevention drugs known as PrEP are highly effective, but many at risk don't know about it

Despite highly effective HIV prevention drugs on the market, only a fraction of those at risk in the U.S. are taking them — or even know it's an option.

It's called pre-exposure prophylaxis, or PrEP,  and it is about 99% effective to prevent HIV infection through sexual contact when taken as prescribed. But only about one-third of the 1.2 million Americans who could benefit from the medication are taking it, according to an estimate from the Centers for Disease Control and Prevention. 

LaTonia Wilkins told CBS News she never knew PrEP was for people like her, even after she had an HIV scare.