Article Betacoronavirus Adaptation to Humans Involved Progressive Loss of Hemagglutinin-Esterase Lectin Activity Graphical Abstract Highlights d Adaption of coronaviruses OC43 and HKU1 to humans involved loss of HE lectin function d OC43 HE receptor binding site was lost via progressive accumulation of mutations d Loss of HE receptor binding alters sialate-9-O-acetylesterase receptor destroying activity d Balance of receptor binding and receptor destruction contributes to host tropism Authors Mark J.G. Bakkers, Yifei Lang, Louris J. Feitsma, ..., Martijn A. Langereis, Eric G. Huizinga, Raoul J. de Groot Correspondence