RT Journal Article SR Electronic(1) A1 He, Liang A1 Jiang, Kaijun A1 Wu, Qiwen A1 Duan, Zhiqiang A1 Xu, Haixu A1 Liu, Jingjing A1 Cui, Zhu A1 Gu, Min A1 Wang, Xiaoquan A1 Liu, Xiaowen A1 Liu, XiufanYR 2014 T1 Two amino acid substitutions in the haemagglutinin of the 2009 pandemic H1N1 virus decrease direct-contact transmission in guinea pigs JF Journal of General Virology, VO 95 IS 12 SP 2612 OP 2617 DO https://doi.org/10.1099/vir.0.067694-0 PB Microbiology Society, SN 1465-2099, AB The 2009 pandemic H1N1 influenza A virus spread across the globe and caused the first influenza pandemic of the 21st century. Many of the molecular factors that contributed to the airborne transmission of this pandemic virus have been determined; however, the direct-contact transmission of this virus remains poorly understood. In this study, we report that a combination of two mutations (N159D and Q226R) in the haemagglutinin (HA) protein of the representative 2009 H1N1 influenza virus A/California/04/2009 (CA04) caused a switch in receptor binding preference from the α2,6-sialoglycan to the α2,3-sialoglycan receptor, and decreased the binding intensities for both glycans. In conjunction with a significantly decreased replication efficiency in the nasal epithelium, this limited human receptor binding affinity resulted in inefficient direct-contact transmission of CA04 between guinea pigs. Our findings highlight the role of the HA gene in the transmission of the influenza virus., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.067694-0