Seasonal influenza epidemics and influenza pandemics caused by influenza A virus(IAV)has resulted in millions of deaths in the world.The development of anti-IAV vaccines and therapeutics is urgently needed for prevention and treatment of IAV infection and for controlling future influenza pandemics.Hemagglutinin(HA)of IAV plays a critical role in viral binding,fusion and entry,and contains the major neutralizing epitopes.Therefore,HA is an attractive target for developing anti-IAV drugs and vaccines.Here we have reviewed the recent progress in study of conformational changes of HA during viral fusion process and development of HA-based antiviral therapeutics and vaccines.
