Asymptomatic SARS-CoV-2 seropositivity: patients with childhood-onset rheumatic diseases versus healthy children

Objective We aimed to find out the asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence among pediatric patients with rheumatic diseases and healthy children and to compare them with each other. Methods Patients with familial Mediterranean fever (FMF), juvenile idiopathic arthritis (JIA), and juvenile systemic lupus erythematosus (jSLE) and healthy children as healthy control (HC) group who remained asymptomatic during the pandemic are examined by ELISA immunoglobulin (Ig) A and IgG tests in this cross-sectional study. Results Overall, 149 subjects (90 females) were included in the study. While IgA was positive in 15 subjects (10%) (HC: 8, jSLE: 3, FMF: 2, JIA: 2; p = 0.196), IgG was positive in 14 subjects (9.4%) (HC: 7, JIA: 5, FMF: 1, jSLE: 1; p = 0.156). Nineteen subjects (12.75%) were IgA or IgG positive (HC: 8, JIA: 5, jSLE: 3, FMF: 3; p = 0.644). Although not significant, seropositivity was more often in HC group. Both IgA and IgG positivity were not found to be related to age, sex, underlying rheumatic diseases, and received treatments of the patients. Conclusion We revealed that patients with childhood-onset rheumatic diseases, even if they receive immunosuppressive medication such as biologic or conventional disease-modifying anti-rheumatic drugs, might have an asymptomatic SARS-CoV-2 infection, similarly to their healthy peers. Key points• Although it has been already known that children are most likely to have asymptomatic SARS-CoV-2 infection, there is a lack of data on the disease course of children with rheumatic disease.• There was no significant difference regarding the asymptomatic SARS-CoV-2 seropositivity rates between healthy children and the patients with childhood-onset rheumatic diseases.• Patients with childhood-onset rheumatic diseases, even if they receive immunosuppressive medication, might have asymptomatic SARS-CoV-2 infection, similarly to their healthy peers.