Merck is one of the world's largest pharmaceutical companies. Merck reported 4% revenue ... Argus has a "buy" rating and $100 price target for GILD stock, which closed at $92.92 on Jan. 23.

Meanwhile, the value of five pharmaceutical companies fell in 2017 as Merck & Co, Celgene, GlaxoSmithKline (GSK), Allergan and Shire all saw their market capitalisation decline.

More importantly, there are lots of other types of vaccines that are key growth drivers for some pharmaceutical companies. Here's what you need to know about investing in the top vaccine stocks ...

Tax avoidance by American pharmaceutical companies is a very real problem ... in tax to the U.S. Treasury on global earnings of over $100 billion, a remarkably small sum. Such reforms would ...