Many people are getting the flu vaccine to help avoid becoming ill thiswinter. While the symptons of headache, nausea and fatigue are usuallyassociated with the flu, they’re also a warning of another serious healthproblem — carbon monoxide poisoning. John Ruff is a spokesman for AlliantEnergy. Ruff says this is usually the first time in months that furnaces areon and that it’s better to be safe than sorry. He recommends having aheating professional look over your unit.