Did you forget? H1N1 SWINE FLU The 2009 epidemic broke out in 214 countries and killed over 18,000 people, according to laboratory-confirmed deaths. In Hong Kong, 282 patients had severe complications, of whom 80 died. But after studying data on respiratory deaths, researchers estimated the swine flu epidemic could have killed up to 575,000 people, mostly in Southeast Asia and Africa, where access to treatment and prevention resources was more limited.