Anti-SARS-CoV-2 neutralizing IgG and IgA response in pwCF divided by categories. A total of 178 pwCF were eligible for humoral immunity assays. For data analysis, patients were then divided in different categories: non-LTR versus LTR (a,b), pwCF undergoing MMF treatment versus patients under other immunosuppressive therapies (c,d), males versus females (e,f), patients who contracted COVID-19 before vaccination versus those with no previous coronavirus infections (g,h). Wilcoxon Signed Rank test and Mann–Whitney U test were calculated for dependent and independent comparison, respectively. * p < 0.05; ** p < 0.01; *** p < 0.001.