This is important in the context of COVID-19 because the glycan structures on the SARS-CoV-2 S protein interact directly with host molecules, in this case angiotensin-converting enzyme 2 (ACE2) on the surface of respiratory epithelial cells, and therefore influence host–pathogen interactions, viral infectivity, and the immunogenicity of vaccines which are intended to elicit neutralizing antibody responses [11,12]. The gene discussed is PROS1; the disease is COVID-19.