However, we observed a profoundly reduced SP-A level in the subgroup of severe COVID-19 patients (Figure 7D), despite the higher total protein levels observed in this subgroup; highlighting the importance of a relatively preserved level of SP-A in the salivary mucosa of SARS-CoV-2 infected individuals to alleviate the most severe COVID-19 symptomology. Here, SFTPA2 is linked to COVID-19.