摘要
Dear Editor,The influenza H1N1 virus has caused three global pandemics since the beginning of the 20th century(Liu et al.,2015).The first is the notorious Spanish flu in 191&which killed 20-100 million people in the world.It circulated for nearly 40 years and was replaced by influenza H2N2 virus.In 1977,the virus reappeared in Russia and caused global pandemics.It continued to circulate until 2009 when it was replaced by the pandemic H1N1 virus.Influenza H1N1 viruses cause large morbidity and mortality to human society,and will continue to threaten humans.Vaccination is the most effective way to fight against the virus.However,due to rapid mutation of the virus,antigenic drift happens frequently,which leads to inefficiency of influenza vaccines.How to timely identify antigenic variants is an important question in influenza surveillance.
基金
supported by the National Key Plan for Scientific Research and Development of China (2016YFC1200200 and 2016YFD0500300)
the National Natural Science Foundation of China (31500126 and 31671371)
the Chinese Academy of Medical Sciences (2016-I2M-1-005
the Fundamental Research Funds for the Central Universities of China
