Mild SARS-CoV-2 infections and neutralizing antibody titers

01 Jul, 2021

Authors: F Bonfante, P Costenaro, A Cantarutti, CD Chiara, A Bortolami, MR Petrara, F Carmona, M Pagliari, C Cosma, S Cozzani, E Mazzetto, GD Salvo, LD Dalt, P Palma, L Barzon, G Corrao, C Terregino, A Padoan, M Plebani, AD Rossi, D Donà, C Giaquinto

Published in: Pediatrics



Background. Recent evidence suggests that neutralizing antibodies to SARS-CoV-2 may persist over time; however, knowledge regarding pediatric subjects is limited. Methods. A single-center, prospective observational study was conducted on 57 family clusters of COVID-19, including children of neonatal and pediatric age attending the University Hospital of Padua (Italy). For each patient, blood samples were collected for both the quantification of neutralizing antibodies (nAbs) through a Plaque Reduction Neutralizing Test (PRNT) and the detection of anti-nucleocapsid-spike protein IgG/IgM. Results. We analyzed 283 blood samples collected from 152 confirmed COVID-19 cases (82 parents and 70 children/older siblings of median age of 8 years, IQR 4-13), presenting asymptomatic or with mildly symptomatic disease. Despite the decrease of IgG over time, nAbs were found to persist up to 7-8 months in children while adults recorded a modest declining trend. Interestingly, children under 6 years of age, and in particular under 3 years developed higher longlasting levels of nAbs compared to older siblings and/or adults. Conclusion. Mild and asymptomatic SARS-CoV-2 infections in family clusters elicited higher neutralizing antibodies among children.


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