Fig. 1

Associations of anti-SARS-CoV-2 IgM, IgG, and IgA antibodies (NP, RBD, Spike) with risk or protection for Long COVID (LC) symptoms. This graphical summary illustrates statistically significant protective (green) or risk-associated (red) relationships between anti-SARS-CoV-2 antibody responses and LC development or specific LC symptoms. Dotted-line empty rectangles indicate no significant association. Associations are categorized by antigen (all isotypes) or by isotype (all antigens), with each unique association counted once. Cardio: cardiological LC symptoms, ORL: Otorhinolaryngological LC symptoms, Gastro: gastrointestinal LC symptoms, Neuro: neurological LC symptoms, T1: the first timepoint in our study, early convalescence, approximately 40 days following COVID-19 onset. T2: the second timepoint in our study, approximately 6 months following COVID-19 onset; T3: the third timepoint in our study, approximately 1 year following COVID-19 onset. RBD: receptor-binding domain from the spike protein, NP: nucleocapsid protein, VNT: virus neutralization titer. VNT titers ≥ 20 were considered positive for neutralizing antibodies. All identified differential antibody profiles presented p values < 0.05. Statistical tests used: (i) for frequency detection, chi-square or Fisher tests were used; (ii) for antibody levels, Mann‒Whitney tests, and (iii) for correlation analyses, Spearman correlation.