Based on the present bioinformatic analysis (shown in Fig. 1 and Fig. 3) and previous reports, OAS genes are highly expressed in SARS-CoV-2 infected cardiomyocytes and the hearts of COVID-19 patients [23, 38–40], and our qPCR experiments further verified the high expressions of OAS genes in the myocardium of COVID-19-free HF cases (shown in Fig. 2 and Fig. 4). This evidence concerns the gene SMOC1 and hydrops fetalis.