Si Min Chan (Singapore)National University Health System, Singapore Khoo Teck Puat-National University Children's Medical Institute
Author Of 1 Presentation
MILD COVID-19 INFECTION GENERATES DURABLE ANTIBODY RESPONSES IN UNVACCINATED CHILDREN
Antibody titres decline in the months following COVID-19 in adults. COVID-19 is typically milder in children and there is limited data on durability of humoral responses following natural infection in this cohort.
Children aged ≤17 years old with SARS-CoV-2 infection diagnosed by RT-PCR at our centre were recruited between January and July 2021. Subjects underwent serological testing for anti-Spike and anti-N-capsid Immunoglobulin G (IgG) antibodies at time of diagnosis. Subjects underwent point of care testing (POCT) (ASSURE® SARS-CoV-2 IgG/IgM Rapid Test) for total SARS-CoV-2 IgG at 0-6 weeks post diagnosis. POCT testing was repeated with serological testing and testing for SARS-CoV-2 neutralising antibodies (cPASS™ assay) at 3-6 months, 12 months, and 24 months post-diagnosis. Subjects were allowed to be recruited into the study at any timepoint.
The results summarise preliminary data for 23 children. Median age of the cohort was 5.9 years (range 8 months -17 years). None were immunosuppressed or had significant co-morbidities. 21 children had a positive household contact. 12 children were asymptomatic at time of diagnosis; all eventually had asymptomatic or mild disease. There were no cases of multisystem inflammatory syndrome in children, or re-infection in the child or their household contacts. 7/18 (39%) children were already seropositive at time of diagnosis on serology testing. On POCT, at 0-6 weeks, 5/6 (83%) children were seropositive; seropositivity persisted in all children at 3-6 months (n=8) and in 5/6 (83%) children at 12 months (figure 1). The study of temporal kinetics for anti-Spike and anti-N-capsid IgG antibodies, and neutralising antibody titres is still ongoing.
Even mild COVID-19 infection induces durable seroconversion in children with detectable IgG levels at 1 year after infection in the majority.