Although MACROH2A1 is a novel molecule that, to our knowledge, has not been previously reported in association with COVID-19, a causal network analysis using IPA on proteins listed in Supplementary Table 2 identified a regulatory relationship between acyl-CoA synthetase 1 (ACSL1) and MACROH2A1 (Supplementary Fig. 2a). Here, MACROH2A1 is linked to COVID-19.