Patrons at the AMC Movie Theater in Fullerton, where the measles-carrying moviegoer saw the film are said to have been at risk between 11 p.m. April 25 and 4 a.m. April 26. The infected woman’s window of contagion was April 23 through May 1. She didn’t yet know she was infected, according to the Los Angeles Times. Theatergoers at risk could take up to three weeks to show symptoms including rashes and high fevers.