28 Days Later

A group of animal activists free a bunch of chimps, despite warnings that the chimps are infected. The chimps immediately attack. Twenty eight 28 days later, a courier awakens from a coma, in a deserted hosptital. Making his way outside, he approaches a priest for help, but the priest attacks him. Fleeing, he is rescued by some other people, who explain that there is a disease infecting most of the population, making them violent. The group travel some distance to where part of the army has secured an area, but the army chaps, while not infected, have a violent streak of their own...