HealthDay: Mild winters where few people catch the flu tend to be followed by serious flu outbreaks the next year, a new study finds, suggesting that global warming could mean harsher flu seasons ahead. That, at least, is the theory. The study, which appeared Jan. 28 in the journal PLoS Currents: Influenza, shows a correlation between warm U.S. winters and more flu misery the following winter. "But correlation doesn't mean causation," said lead researcher Sherry Towers, a research professor at Arizona State...