It is thought that a lack of symptoms usually indicates a weak immune response.25 To test whether S2–78 IgG can be used for the detection of asymptomatic infection, we analyzed 63 asymptomatic cases (Cohort 4, Table 1) defined as positive either by the NAT or antibody test conducted with a commercial assay (see “Methods“) but without obvious symptoms. Here, BRD2 is linked to infection.