Answer: flu

AnswerCrossword Clue
FLUFever cause
FLUGrippe
FLUIt may be going around
FLUTough bug
FLUCause of chills
FLUCause of many a sick day
FLUReason to stay in bed
FLUH1N1 virus, e.g.
FLUSwine ..
FLUWord after blue or bird
FLUCause of chills and fever
FLUBug that may knock you out
FLUSeasonal malady
FLUShot target
FLUBlue ..: certain strike action
FLUWinter bane
FLUIt goes around in winter
FLUReason to take a sick day
FLUBlue ... (cops' sickout)
FLUBug with two homonyms
fluinfluenza
FLUVaccine target
FLUWinter woe
FLUKind of shot
FLUWinter bug
FLUHard to find shot
FLUCommon illness
FLUWinter ailment
FLUUnwelcome bug
FLUWinter affliction
FLUWorkforce reducer
FLUFall shot
FLU.. shot
FLUCommon viral infection
FLUAffliction formerly called the grippe
FLUPandemic of 1918-19
FLUWorld Health Organization concern
FLUSeasonal strain
FLU... shot
FLUBlue or yuppie follower