Building-level analyses to prospectively detect influenza outbreaks in long-term care facilities: New York City, 2013-2014.

•Rapid detection is needed to limit influenza in long-term care facilities (LTCFs).•We developed a daily analysis to more rapidly detect influenza outbreaks in LTCFs.•Geocoded address fields were used to match case-patient addresses with LTCFs.•Automated building analyses were the first detection method for 55 LTCF outbreaks.•This analysis improved outbreak detection during the 2013-14 influenza season.