Keyword: Zostavax

While immuno-oncology star Keytruda has generated plenty of headlines for Merck lately, the company's vaccine business has been on the upswing, too, thanks to human papillomavirus shot Gardasil 9.

Like any global drugmaker, Merck faced a bevy of challenges in 2017, a year marked by meager growth for the company. Still, there are bright spots in the company's performance, mostly immuno-oncology star Keytruda, and that's continuing to pay off in 2018.