Childhood Humoral Immunity During and After COVID-19 Lockdowns

Coralie Mallebranche; Emeline Vinatier; Julien Lejeune; Tiffanie Bousser; Marie-Alexandra Alyanakian; Céline Beauvillain; Vannina Giacobbi; Isabelle Pellier; Charline Miot

doi:10.1097/INF.0000000000004869

Childhood Humoral Immunity During and After COVID-19 Lockdowns

Pediatr Infect Dis J. 2025 May 23. doi: 10.1097/INF.0000000000004869. Online ahead of print.

Authors

Coralie Mallebranche¹, Emeline Vinatier², Julien Lejeune³, Tiffanie Bousser⁴, Marie-Alexandra Alyanakian⁵, Céline Beauvillain⁶, Vannina Giacobbi⁷, Isabelle Pellier¹, Charline Miot⁶

Affiliations

¹ From the University of Angers, Université de Nantes, Inserm, CNRS, CRCI2NA, SFR ICAT, CHU Angers, Pediatric Immuno-hemato-oncology Unit, Angers, France.
² CHU Angers, Laboratory of Immunology and Allergology, Angers, France.
³ CH Tours, Pediatric Onco-Hematology Unit, Tours, France.
⁴ CH Le Mans, Laboratory of Immunology, Le Mans, France.
⁵ Hôpital Necker-Enfants Malades, Laboratory of Immunology, AP-HP, Paris, France.
⁶ University Angers, Université de Nantes, Inserm, CNRS, CRCI2NA, SFR ICAT, CHU Angers, Laboratory of Immunology and Allergology, Angers, France.
⁷ CH Le Mans, General Pediatric Unit, Le Mans, France.

PMID: 40440706
DOI: 10.1097/INF.0000000000004869

Abstract

Our study, including serum from 3678 hospital inpatients and outpatients sampled before, during and after the COVID-19 lockdown periods, showed a significant decrease in overall IgG levels during the periods of sanitary restriction, particularly in children 3-10 years of age. Few months after the lifting of COVID-19 restrictions, immunoglobulin levels normalized. COVID-19 lockdowns may have induced a transient humoral immune gap.

Keywords: Immunoglobulin G; Immunologic Memory; SARS-CoV-2; non-pharmaceutical interventions.