Course: Long-term Immune Response to SARS-CoV-2 Infection Among Children and Adults After Mild Infection
CME Credits: 1.00
Released: 2022-07-13
Key Points
Question What are the long-term features of the immune response to SARS-CoV-2 in children compared with adults?Findings In this cohort study of 252 family clusters with COVID-19, anti–SARS-CoV-2 spike receptor-binding domain IgG persisted until 12 months after infection in all age groups, showing significant higher antibody peaks for younger individuals at every follow-up time point. Children younger than 3 years were found to develop higher levels of binding antibodies compared with adults older than 18 years.
Meaning This study provided novel insights into the long-term features of the immune response to COVID-19 for different age classes, which could help in optimizing future COVID-19 vaccination strategies and prevention policies.
Abstract
Importance Understanding the long-term immune response against SARS-CoV-2 infection in children is crucial to optimize vaccination strategies. Although it is known that SARS-CoV-2 antibodies may persist in adults 12 months after infection, data are limited in the pediatric population.Objective To examine long-term anti–SARS-CoV-2 spike receptor-binding domain (S-RBD) IgG kinetics in children after SARS-CoV-2 infection.
Design, Setting, and Participants In this single-center, prospective cohort study, patients were enrolled consecutively from April 1, 2020, to August 31, 2021, at the COVID-19 Family Cluster Follow-up Clinic, Department of Women's and Children's Health, University Hospital of Padua. A cohort of 252 COVID-19 family clusters underwent serologic follow-up at 1 to 4, 5 to 10, and more than 10 months after infection with quantification of anti–S-RBD IgG by chemiluminescent immunoassay.
Exposures SARS-CoV-2 infection.
Results Among 902 study participants, 697 had confirmed SARS-CoV-2 infection, including 351 children or older siblings (mean [SD] age, 8.6?[5.1] years) and 346 parents (mean [SD] age, 42.5?[7.1] years). Among 697 cases, 674 (96.7%) were asymptomatic or mild. Children had significantly higher S-RBD IgG titers than older patients across all follow-up time points, with an overall median S-RBD IgG titer in patients younger than 3 years 5-fold higher than adults (304.8 [IQR, 139.0-516.6] kBAU/L vs 55.6 [24.2-136.0] kBAU/L, P?<?.001). Longitudinal analysis of 56 study participants sampled at least twice during follow-up demonstrated the persistence of antibodies up to 10 months from infection in all age classes, despite a progressive decline over time.
Conclusions and Relevance In this cohort study of Italian children and adults following SARS-CoV-2 infection different kinetics of SARS-CoV-2 antibodies were found across several age classes of individuals with asymptomatic or mild COVID-19, which could help in optimizing COVID-19 vaccination strategies and prevention policies. This work provides further evidence of sustained immune response in children up to 1 year after primary SARS-CoV-2 infection.
Educational Objective
To identify the key insights or developments described in this article
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