Main exposure variable Influenza-like illness (ILI), defined as fever (temperature of 100 F [37.8 C] or greater) and a cough and/or a sore throat without a known cause other than influenza.
Main exposure variableInfluenza-like illness (ILI), defined as fever (temperature of100 F [37.8 C] or greater) and a cough and/or a sorethroat without a known cause other than influenza.