The cumulative incidence rate of infections in the overall cohort of 63 COVID-19 patients was 3.08 per 100 person-week (1.3–6.8 95% CI), while in those having circulating IgM memory B cells ≤ 26/μl, it was 3.69 per 100 person-week (1.6–8.2 95% CI). The gene discussed is CD40LG; the disease is COVID-19.