Six weeks after the first vaccine dose (three weeks after the second dose) all vaccinees produced high levels of anti-S1 IgG and total Ig (IgG, IgA, and IgM) antibodies, and the mean anti-S1 antibody levels were significantly higher compared to antibody levels in hospitalized COVID-19 patients (p<0.0001) (Figure 6A). Here, CD40LG is linked to COVID-19.