Level and Duration of IgG and Neutralizing Antibodies to SARS-CoV-2 in Children with Symptomatic or Asymptomatic SARS-CoV-2 Infection

Abstract

There are conflicting data about level and duration of Abs to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children after symptomatic or asymptomatic infection. In this human population, we enrolled adults and children in a prospective 6-mo study in the following categories: 1) symptomatic, SARS-CoV-2 PCR + (SP + ; children, n 5 8; adults, n 5 16), 2) symptomatic, PCR À , or untested (children, n 5 27), 3) asymptomatic exposed (children, n 5 13), and 4) asymptomatic, no known exposure (children, n 5 19). Neutralizing Abs (nAbs) and IgG Abs to SARS-CoV-2 Ags and spike protein variants were measured by multiplex serological assay. All SP + children developed nAb, whereas 81% of SP + adults developed nAb. Decline in the presence of nAb over 6 mo was not significant in symptomatic children (100 to 87.5%; p 5 0.32) in contrast to adults (81.3 to 50.0%; p 5 0.03). Among children with nAb (n 5 22), nAb titers and change in titers over 6 mo were similar in symptomatic and asymptomatic children. In children and adults, nAb levels postinfection were 10-fold lower than those reported after SARS-CoV-2 mRNA vaccination. Levels of IgG Abs in children to SARS-CoV-2 Ags and spike protein variants were similar to those in adults. IgG levels to primary Ags decreased over time in children and adults, but levels to three spike variants decreased only in children. Children with asymptomatic or symptomatic SARS-CoV-2 infection develop nAbs that remain present longer than in adults but wane in titer over time and broad IgG Abs that also wane in level over time. However, nAb levels were lower postinfection than those reported after immunization. ImmunoHorizons, 2022, 6: 408-415.

IgG antispike persistence and immunophenotype in children infected by SARS‐CoV‐2

“…Almost half of the children in the asymptomatic group tested negative. Previous studies have suggested that humoral immunity persists longer based on symptoms derived from the infection 9,13 . However, this fact has not yet been confirmed in children and cannot be derived from our results, even though they are along these lines.…”

“…It is already known that there is a gradual decrease in antibodies after primary infection in adults. 9,10 Previous studies reported remarkable persistence in the paediatric population. 1 In our study, we observed that all patients tested <1 year after acute infection were still positive for antispike IgG, and no patient tested negative for serology before day 411 after the infection.…”

“…Few studies have been published on the persistence of SARS‐CoV‐2 antibodies in children. It is already known that there is a gradual decrease in antibodies after primary infection in adults 9,10 . Previous studies reported remarkable persistence in the paediatric population 1 .…”

Duration of immunity to SARS-CoV-2 in children after natural infection or vaccination in the omicron and pre-omicron era: A systematic review of clinical and immunological studies

“…Khaitan et al,. as part of the DISCOVER study ( 34 ), measured neutralizing Abs (nAbs) and IgG Abs to SARS-CoV-2 Ags and spike protein variants in symptomatic and asymptomatic children. They found that children developed nAbs that remained detectable longer than in adults but waned in titer over time and broad IgG Abs that also waned in level over time.…”

Antibody-mediated cellular responses are dysregulated in Multisystem Inflammatory Syndrome in Children (MIS-C)

“…Of note, individuals that were in the COVID-19 positive asymptomatic pediatric controls group came to the hospital for some reason other than SARS-CoV-2 and were enrolled in this study because they were incidentally found to be SARS-CoV-2 positive by nuclei acid testing. (Khaitan et al, 2022). We also utilized sequencing data from 20 additional MIS-C samples collected at the Karolinska Institute.…”