CD40LG and COVID-19: Although an increase in anti-N antibody seroprevalence could compromise the detection of BTIs by anti-N antibody alone, future studies using anti-N antibody test (IgG and/or IgM) in combination with RT-PCR or antigen test could still identify BTIs among COVID-19-naïve vaccinees (anti-N negative during the window period before seroconversion) and distinguish them with reinfection among COVID-19-recovered cases (anti-N positive).