Seroprevalence of SARS‐CoV‐2 infections among children visiting a hospital

Abstract

Importance In this study, we retrospectively investigated the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) antibodies within serum samples from children in Beijing, China. These findings provide preliminary guidance regarding population susceptibility to SARS‐CoV‐2, which will aid in establishing policy toward coronavirus disease 2019 (COVID‐19) prevention and control. Objective To understand the seropositivity of anti‐SARS‐CoV‐2 IgM/IgG antibodies among children in Beijing, China, evaluate the susceptibility of children in Beijing to SARS‐CoV‐2, and provide prima facie evidence to guide SARS‐CoV‐2 prevention and control. Methods IgM/IgG antibody kits (colloidal gold) were used to conduct preliminary screening of SARS‐CoV‐2 IgM/IgG antibodies in serum samples of children who presented to Beijing Children’s Hospital, Capital Medical University, having fever or requiring hospitalization, from March 2020 to August 2020. Statistical analysis of anti‐SARS‐CoV‐2 antibody seropositivity was performed according to the children’s general demographic characteristics, timing of admission to hospital, presence of pneumonia, and viral nucleic acid test results. Results The study included 19 797 children with both IgM and IgG antibody results. Twenty‐four children had anti‐SARS‐CoV‐2 IgM‐positive results (positive rate of 1.2‰), twelve children had anti‐SARS‐CoV‐2 IgG‐positive results (positive rate of 0.6‰). Viral nucleic acid test results were negative for the above‐mentioned children with positive antibody findings; during the study, two children exhibited positive viral nucleic acid test results, but their anti‐SARS‐CoV‐2 IgM/IgG antibody results were negative. Anti‐SARS‐CoV‐2 IgM antibody seropositivity was higher in the <1‐year‐old group than in the ≥6‐year‐old group. The rates of anti‐SARS‐CoV‐2 IgM seropositivity was highest in August from March to August; IgG results did not significantly differ over time. The rates of anti‐SARS‐CoV‐2 IgM or IgG seropositivity among children with and without suspected pneumonia did not significantly differ between groups. Interpretation During the study period, the rates of anti‐SARS‐CoV‐2 IgM/IgG antibody seropositivity were low among children who presented to Beijing Children’s Hospital, Capital Medical University. The findings suggest that children in Beijing are generally susceptible to SARS‐CoV‐2 infection; COVID‐19 prevention and control measures should be strengthened to prevent disease in children.

Assessment of SARS-CoV-2 Anti-Spike IgG Antibody in Women and Children in Madinah, Saudi Arabia: A Single-Center Study

“…Our results revealed that the seropositivity rate in children is similar according to sex, with 61.8% seropositivity observed in males and 55.2% in females. This result is inconsistent with finding of previous study that reported higher seropositivity rate in boys than girls [ 23 ]. However, our previous study found a higher SARS-CoV-2 viral load (based on lower Ct values) among females compared with males [ 24 ].…”

Evolution of SARS-CoV-2 IgG Seroprevalence in Children and Factors Associated with Seroconversion: Results from a Multiple Time-Points Study in Friuli-Venezia Giulia Region, Italy

“…To our knowledge, no recent studies have evaluated anti-SARS-CoV-2 antibodies prevalence in Italy in the same period, so we lack data for a comparison. Of note, no significant differences in anti-SARS-CoV-2 IgG positivity were found in a large pediatric cohort evaluated in China over a 6-month period between March and August 2020 [ 19 ]. Data from sero-surveillance programmes implemented in England similarly showed a plateau in seropositivity in children between January and August 2021, followed by a large increase starting from September 2021, probably due to the deployment of the vaccination campaign [ 20 ].…”

Immune response to SARS‐CoV‐2 in children: A review of the current knowledge

“…Additionally, there is an increase in IgG specific B‐cell rates in children with SARS‐CoV‐2, indicating a rapid and effective humoral immune response. 65 , 66 In a seroprevalence pediatric study ( n = 208), children aged 10–16 years have 2–3 times higher positive antibody titers than children under 10 years old. 67 Possible etiologies that enhance the innate immune response and humoral activity constitute a) the decreased expression of the ACE2 receptor in the upper respiratory epithelium of younger children and b) the antibody cross‐reactivity with other common cold CoVs, in which older children are more frequently exposed to.…”

“…Children often experience robust antibody production within the first 3 weeks post infection and an estimated seroconversion time to IgG antibodies in the first week. Additionally, there is an increase in IgG specific B‐cell rates in children with SARS‐CoV‐2, indicating a rapid and effective humoral immune response 65,66 . In a seroprevalence pediatric study ( n = 208), children aged 10–16 years have 2–3 times higher positive antibody titers than children under 10 years old 67 .…”