TO the pantheon of social arbiters who came up with the firm handshake, the formal bow and the air kiss, get ready to add a new fashion god: the World Health Organization, chief advocate of the "elbow bump." If the avian flu goes pandemic while Tamiflu and vaccines are still in short supply, experts say, the only protection most Americans will have is "social distancing," which is the new politically correct way of saying "quarantine." But distancing also encompasses less drastic measures, like wearing face masks, staying out of elevators — and the bump. Such stratagems, those experts say, will...