28 Weeks Later Plot

From MoviesOnline:

Lead by director Juan Carlos Fresnadillo, "28 Weeks Later" picks up six months after the Rage virus has decimated the city of London. The US Army has restored order and is repopulating the quarantined city, when a carrier of the Rage virus enters London and unknowingly re-ignites the spread of the deadly infection, wreaking havoc on the entire population.