The ongoing Phase 3 clinical trial of Pfizer/BioNTech's coronavirus vaccine confirms its protection lasts at least six months after the second dose, the companies said Thursday. It's the first look at how long protection for a coronavirus vaccine lasts, and while six months is a modest target, it's longer than the 90 days of protection been the best estimate offered to date. The vaccine remains more than 91% effective against disease with any symptoms for six months, the companies said. And it appeared to be fully effective against the worrying B.1.351 variant of the virus...