Seroprevalence of SARS-CoV-2 Antibodies in Children and Adults in St. Louis, Missouri, USA

mSphere. 2021 Feb 3;6(1):e01207-20. doi: 10.1128/mSphere.01207-20.


Reported coronavirus disease 2019 (COVID-19) case counts likely underestimate the true prevalence because mild or asymptomatic cases often go untested. Here, we use a sero-survey to estimate the seroprevalence of IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the St. Louis, MO, metropolitan area in a symptom-independent manner. Five hundred three adult and 555 pediatric serum/plasma samples were collected from patients presenting to Barnes-Jewish Hospital or St. Louis Children's Hospital between 14 April 2020 and 12 May 2020. We developed protocols for in-house enzyme-linked immunosorbent assays (ELISAs) using spike and nucleoprotein and used the assays to estimate a seroprevalence rate based on our samples. Overall IgG seropositivity was estimated to be 1.71% (95% credible interval [CI], 0.04% to 3.38%) in pediatric samples and 3.11% (95% CI, 0.92% to 5.32%) in adult samples. Seropositivity was significantly lower in children under 5 years of age than in adults, but rates between adults and children aged 5 or older were similar. Of the 176 samples tested from children under 4 years of age, none were positive.IMPORTANCE This study determined the percentages of both children and adult samples from the greater St. Louis metropolitan area who had antibodies to SARS-CoV-2 in late April to early May 2020. Approximately 1.7 to 3.1% of the tested individuals had antibodies, indicating that they had previously been infected by SARS-CoV-2. These results demonstrate that the extent of infection was about 10 times greater than the number of confirmed cases at that time. Furthermore, it demonstrated that by 5 years of age, children were infected to an extent similar to that of adults.

Keywords: COVID-19; SARS-CoV-2; St. Louis; serology; seroprevalence.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Antibodies, Viral / blood*
  • Antibodies, Viral / immunology*
  • COVID-19 / blood*
  • COVID-19 / epidemiology
  • COVID-19 / immunology*
  • Child
  • Child, Preschool
  • Enzyme-Linked Immunosorbent Assay / methods
  • Female
  • Humans
  • Immunoglobulin G / blood
  • Immunoglobulin G / immunology
  • Infant
  • Male
  • Middle Aged
  • Missouri / epidemiology
  • SARS-CoV-2 / immunology*
  • Seroepidemiologic Studies
  • Young Adult


  • Antibodies, Viral
  • Immunoglobulin G