It is unsurprising that we found only a non-significant trend towards higher CRP and D-dimer levels in subjects with lower 25(OH)D levels, and we also failed to find other associations between serum 25(OH)D and the markers of inflammation and thrombophilia which typically characterize severe COVID-19, because all patients recruited to the study had severe disease at baseline (SARS-CoV-2 pneumonia requiring supplemental oxygen). This evidence concerns the gene CRP and thrombophilia.