Many humans may already have some immunity to H5N1 bird flu, raising hopes that the virus could pose less of a threat than previously thought, new research suggests.

H5N1 bird flu has infected growing numbers of people worldwide in recent years, but this week saw something new: the first recorded human case of an H5N5 avian influenza virus. What is this virus and how concerned about it should we be? In early November ...

Health officials are making a renewed call for vigilance against bird flu, but some experts are puzzling over why reports of new human cases have stopped. Has the search for cases been weakened by government cuts? Are immigrant farm workers, who have ...

Add Yahoo as a preferred source to see more of our stories on Google. A first-of-its-kind trial has been launched to test a new vaccine for bird flu in humans, amid the "real possibility" of human-to-human transmission. Thousands of people in the UK are ...

Bird flu viruses are a particular threat to humans because they can replicate at temperatures higher than a typical fever, one of the body's ways of stopping viruses in their tracks, according to new research led by the universities of Cambridge and Glasgow.

Changing vaccine recommendations could be partly to blame.