Six polio vaccination workers were killed in attacks in Pakistan since Monday . A Taliban commander in northwest Pakistan banned polio vaccines . Bin Laden was killed by U.S. forces in May 2011 . Pakistan is one of 3 countries where polio remains endemic , WHO says . Score: 6
Six polio vaccination workers were killed in attacks in Pakistan since Monday . A Taliban commander in northwest Pakistan banned polio vaccines . Pakistan is one of 3 countries where polio remains endemic , WHO says . Score: 6