IL37 and COVID-19: In fact, our group previously reported that individuals with severe COVID-19 presented higher levels of SIgA, interferons (IFN) type I (IFN-α and IFN-β) and type II (IFN-γ), and interleukin (IL)-37 in nasopharyngeal and oropharyngeal swabs samples as compared to the groups with mild COVID-19 and individuals with other respiratory infections (9).