In this July 21, 2009 file photo, Microsoft co-founder Bill Gates makes remarks at the National Conference of State Legislatures held at the Pennsylvania Convention Center in Philadelphia. In his second annual letter, Gates says investment in science and technology can leverage those dollars and make more of a difference than charity and government aid alone. (AP Photo/Matt Rourke, File)

A view of Merck Pharmaceuticals in Lansdale , Pennsylvania . The largest US HIV/AIDS health care provider on Monday accused Merck of price-gouging its AIDS treatment Isentress and banned the drug giant's sales reps from its clinics in protest. Photo:/AFP