Saliva samples collected from acutely infected hospitalized patients (n = 35, COV+), vaccinated recovered COVID-19 outpatients (n = 13, COV + VAC+), and vaccinated infection naïve patient samples (n = 13, COV- VAC+) were assayed by EFIRM anti-RBD IgG/IgM/IgA. Here, CD40LG is linked to COVID-19.