SARS-CoV-2 Seropositivity Among Pediatric Patients: A Prospective Study

Background: The Covid-19 pandemic began in late 2019 and quickly spread throughout the world. In children, mortality and morbidity from Covid-19 are low, with the majority of infected children experiencing asymptomatic or mild disease. While serology testing is not used for diagnosing acute Covid-19, seropositivity may be useful in establishing population-wide prevalence and herd-effect immunity. The purpose of this study was to evaluate the incidence and characteristics of seropositivity among children, as well as utilizing antibody titers to explore immunity over time.

Methods: A single-center prospective epidemiological survey was conducted in Jerusalem, Israel between October 2020 and January 2021. Children having blood drawn in the pediatric emergency department were tested for Sars-CoV-2 IgG antibodies using the Abbott Architect and DiaSoren Liaison antibody assays; seropositivity was a positive assay on both kits. Parents also completed a questionnaire with relevant demographic information and specific Covid-19 history of exposure.

Results: 914 children participated in the study. 10% (n=90) tested positive for IgG Sars-CoV-2 antibodies, of which 26 (30%) had no known history or exposure to Covid-19, i.e. asymptomatic, unidentified carriers. A sustained antibody response was identified through 120 days post-exposure. No correlation was found between antibody levels and time from exposure or type of exposure. Children who experienced symptomatic primary Covid-19 or developed Pediatric Multisystem Inflammatory Syndrome had higher antibody levels at time of testing.

Conclusion: The pediatric population has a relatively high seropositivity rate and presents a significant source of unsuspected viral carriage, with a correlation between disease severity and antibody titers.