SERPINA3 and COVID-19: Admittedly, the marginal sequence homologies cannot be used to definitively argue that the antiprotease specificities of bacterial SERPIN homologs closely mirror those of the asthma-relevant and COVID-19-relevant SERPINe1 and SERPINa3, or whether the bacterial proteases might hasten or hinder the SARS-CoV-2 spike mechanism of host-cell entry.