28 Weeks Later (2007)

The movie starts with a flashback to the initial 28 days. Don (Robert Carlyle) and his wife are holed up in a house, avoiding those infected by the Rage virus. After helping a stranger by allowing him into the house, the infected break in. During the turmoil and death, Don leaves his still alive and not yet infected wife to save his own skin. It's now 28 weeks later and after being taken over by the US army, mainland Britain is deemed safe and is being repopulated. Don’s two children return to live with him. Shortly after their arrival, they leave the safe zone to see their old house. They discover their mother, still alive but a carrier. She’s brought back to the safe zone and is considered a possible cure for Rage. Soon afterwards though she infects Don who does succumb to the virus. He escapes the hospital, starts infecting others and gives the army cause to start killing the infected.