作者单位:Global Influenza Programme, World Health Organization, 20 avenue Appia, CH-1211 Geneva 27, Switzerland[1]Office for Disease Control and Emergency Response, Chinese Centre for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, PR China[2]Beijing Center for Disease Prevention and Control, 16 Hepingli Middle Street, Beijing 100013, China[3]