When reactivity to IgG subclasses (IgG1, IgG2, IgG3, and IgG4) for the 20 COVID-19 inpatient samples and 20 malaria exposed samples were characterized, both COVID-19 samples and malaria samples were primarily reactive to IgG1 and IgG3 subclasses (Fig. S3). Here, IGHG3 is linked to COVID-19.