Gilead's (GILD 0.07%) HIV drug Truvada was approved to prevent infection back in July of 2012, but only this month has the CDC come out with an endorsement backing its use as a prophylactic. This could potential lead to huge sales for Gilead as an estimated 500,000 fall within the CDC's new guidelines for the roughly $13,000 per year treatment.

In this episode of The Motley Fool's health-care show Market Checkup, analysts David Williamson and Michael Douglass discuss the CDC's endorsement, why Truvada may struggle to hit such lofty sales figures and  why the insurance industry, already upset with Gilead, may push back.