The results with the 84 sera from all 37 patients showed that the proportion of sera possessing either IgG or IgM antibodies varied with the time of serum collection after RT-qPCR diagnosis of infection, being 100% for sera collected on days 0–10 and 51–65 after the RT-qPCR test and varying between 92 to 44% for other time periods (Table 2). Here, CD40LG is linked to infection.