C4A and infection: Inactivated EV-A71 vaccines that developed based on the C4 genotype strain circulating throughout mainland of China were licensed in the end of 2015 [48–50], and will be used to prevent EV-A71–related HFMD in 2016; although an inactivated EV-A71 vaccine derived from C4 subgenotype strain could be effectively used to induce adequate protective immunity against infection by most of the predominant circulating EV-A71 strains [43], it doesn't work for CV-A6.