CD40LG and infection: Serologicalassays to detect SARS-CoV-2 antibodies are rapidly becoming available and will becritical to estimate the prevalence of infections, including those who areasymptomatic.8 Following infection, detectable IgM and IgG antibodiesdevelop within days to weeks of symptom onset in most infectedindividuals.9, -11 While it ispresently premature to use such assays to determine whether individuals are immuneto reinfection, there may be greater current value in utilizing an antibody test’snegative predictive value.