CDC and the World Health Organization (WHO) are continuing to investigate the multicountry outbreak of severe acute respiratory syndrome (SARS). Infection with a novel coronavirus has been implicated as a possible cause of SARS. This report updates information on U.S. residents with SARS and summarizes the clinical histories of the five U.S. residents identified as of April 9, 2003, who have both suspected SARS and laboratory evidence of infection with a novel coronavirus.