For the less pathogenic human coronaviruses, hCoV‐229E uses CD13 to infect cells, 25  OC43 and HKU1 bind to 9‐O‐acetylated sialic acid (Neu5,9Ac2), 26  and NL63 uses ACE2 to bind to host cells. 27  NL63 and SARS‐CoV first anchor to cells via heparan sulfate proteoglycans before interacting with the ACE2 entry receptor,19, 27, 28 but this binding alone is not sufficient for infection. 19  In fact many viruses, not just coronaviruses, utilise heparan sulfate on cell surfaces for initial binding. 29  Feline infectious peritonitis virus uses CD13 (aminopeptidase N) or CD209 to bind to its host cells. 15  Bovine coronavirus binds to 9‐O‐acetylated sialic acid on its host cells. 30