As suggested by the analysis of these clinically defined sera (Figure 1B) and by our time course of VZV seroconversion after primary infection (Figure 2), the portfolio of IgM antibodies against individual recombinant antigens may enable the serological differentiation between chickenpox (ORFs 4, 14, 49, and 68) and herpes zoster (only ORF68). The gene discussed is CD40LG; the disease is infection.