Rare flu strains could be key to super-vaccine

Research suggests that unfamiliar flu strains cause immune system to release broadly effective antibodies. Rarer forms of flu may be the key to producing a vaccine giving protection against many different strains, scientists believe. Research suggests that immunisation against bird flu strains that do not usually threaten humans may provide the nearest thing yet to a universal flu vaccine. Exposure to an unfamiliar flu strain causes the immune system to release broadly effective antibodies, the study shows. The discovery raises the possibility of vaccinating people against H5N1 and H7N9 bird flu strains, though neither has yet caused an epidemic. Both strains have caused serious and sometimes fatal infections in Asia, typically passing from birds to people via poultry. But neither has spread through populations from person-to-person. Research suggests that although such transmission is possible, it is extremely difficult. The secret to producing a universal flu vaccine is to find a way of targeting the stem rather than...