Seroprevalence of SARS-CoV-2 antibodies in children with nephrotic syndrome and chronic kidney disease: a cross-sectional study from India

Background There is a paucity of literature on the seroprevalence of SARS-CoV-2 antibodies among pediatric patients with underlying kidney disorders; few serosurveys among healthy children have shown seropositivity of 20–65% after different waves of infections. Methods The study had a cross-sectional design and was conducted between January 2023 and July 2023; 163 children and adolescents (1–18 years) with nephrotic syndrome and chronic kidney disease (CKD) were screened for Anti-Spike SARS-COV-2 IgG antibodies as detected by a quantitative chemiluminescence immunoassay. Children with nephrotic syndrome, both steroid sensitive (SSNS) and steroid resistant (SRNS) were enrolled during disease remission. Correlation of SARS-CoV-2 seropositivity status was done with age, gender, disease type, treatment duration, immunosuppressants, previous SARS-CoV-2 infection, and immunization status. Results Of 163 children (63.8% boys) with median age of 9 years; 101 (62%) had underlying nephrotic syndrome (61 SSNS and 40 SRNS), and 62 (38%) children had CKD. Seroprotective titers for SARS-COV2 antibodies were present in 100 (61.3%) children. The median titers for all patients were 37.1 BAU/mL; for nephrotic syndrome they were 27.1 BAU/mL and for CKD they were 76.7 BAU/mL ( p = 0.0033). A total of 43 (26.4%) children had high positive antibody levels (> 200 BAU/ml). Among those with nephrotic syndrome 60.7% with SSNS and 43.5% SRNS had seropositive titers. Only 4 (2.5%) children had a history of previous COVID infection and 6 (3.7%) were vaccinated. Conclusions In a largely unvaccinated population of children with nephrotic syndrome and CKD, 61.3% were seropositive for SARS-CoV-2 IgG antibody indicating a past asymptomatic infection; titers were significantly higher in CKD compared to nephrotic syndrome. Graphical abstract A higher resolution version of the graphical abstract is available as Supplementary information