I'm thinking airplanes. Politicians, high-level bureaucrats, and celebrities practically spend their lives jetting around the world on airplanes, and airplanes are enclosed spaces with recirculated air. A similar example: When retirement homes get an outbreak of Legionnaires' Disease, the source is almost always found to be in the ventilation system and recirculation of air. Cruise ships occasionally have similar problems with outbreaks of illness: Lots of passengers crowded together breathing the same recirculated air-conditioned air.
Anyway, in my opinion the use of aircraft and long flights to far-off destinations would be an easy explanation for why high-level officials and celebs seem to be catching the bug so much. Even if it's a private jet, you're breathing the same air as the crew and help, who may have picked it up in their own travels. Frankly, I myself wouldn't be doing any long intercontinental flights right about now.
If planes are the cause, then it's kind of a "tax on rich people." Politicians are going to have to start campaigning from home, via cameras and satellite links. No more jetting around the country and then shaking hands and kissing babies. (At least until aircraft redesign their air systems to include more fresh air exchange and/or sanitation filters.)