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Background

Understanding community SARS-CoV-2 seroprevalence in children is vital in helping understand the epidemiology of the virus and informing COVID-19 public health policy.

Methods

An ongoing community-based repeat cross-sectional seroprevalence study recruited participants aged 0-24 year between October 2019 and August 2020 across 8 regions in England. Participants were predominantly recruited by mail-out to postcodes with Index of Material Deprivation (IMD) distribution representative of the region. Serum samples, demographics and symptom data were obtained, and samples processed analysed by Abbott nucleocapsid and a Public Health England in-house Receptor Binding Domain (RBD) assays to determine the presence of antibodies against SARS-CoV-2. Combined adjusted seroprevalence estimates were calculated incorporating both RBD or Abbott (sensitivity 96.9%, specificity 96.9%).

Results

Of the 1145 participants recruited, 54 (4.7%) were seropositive by Abbott and 56 (4.9%) by RBD. Between June and August 2020 adjusted seroprevalence in 0-4 year olds was 1% (N= 54, CI 0-8) compared with 12.6% (N=114, CI 6.3-20.4) in 20-24 year olds. A logistic regression analysis demonstrated Black and Minority Ethnic (BAME) participants had higher risk of SARS-CoV-2 infection than white participants (multivariate analysis OR 2.9, CI 1.28-6.57, p = 0.011). Risk was inversely related to deprivation (p = 0.003 across IMD quintiles, OR 0.16 for lowest compared to the highest IMD quintile). 16/34 antibody positive participants reported no flu-like symptoms.

Conclusions

A small but significant minority of children had evidence of infection, and this was higher in BAME participants, although co-morbid risk factors such as obesity and type 2 diabetes are less likely in this paediatric population compared with adult cohorts. Ongoing sampling through the second wave of COVID-19 in England, with enhanced BAME recruitment, will further interrogate this association.

Funded by National Institute for Health Research (NIHR)

Clinical Trial Registration

ClinicalTrials.gov Identifier: NCT04061382

Background

Patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) produce both mucosal and systemic antibodies. Recent cohort studies have shown that in some mild or asymptomatic SARS-CoV-2 cases, serum antibodies may be transient whereas mucosal antibodies were still measurable. Nonetheless, humoral immunity is often only measured in serum while little attention has been paid to saliva. We aimed to assess the serum and saliva SARS-CoV-2 antibody prevalence in children in the Netherlands.

Methods

This prospective cross-sectional multicenter study included children attending medical services and requiring venipuncture at one of the seven participating secondary and tertiary care hospitals located in the North-West of the Netherlands during 24 consecutive weeks (April to October 2020). Prevalence of specific IgG and IgA antibodies against SARS-CoV-2 spike, receptor binding domain of spike (RBD) and nucleocapsid proteins were evaluated in serum with the WANTAI RBD total antibody assay and in serum and saliva with a Luminex assay.

Results

In our sample of 517 children, we found a prevalence of SARS-CoV-2 RBD IgG of 3.7% (CI 2.1 – 5.9) in saliva and 3.3% (CI 1.9 – 5.3) in serum. 56% (9/16) of children with RBD IgG antibodies in saliva were negative in serum. While prevalence of RBD IgG in serum was 3.3% in the WANTAI assay, the antibody prevalence in either serum or saliva was between 6.1% and 19.6% in the combined multi-isotype (IgG/IgA) multi-antigen assays (spike, RBD or nucleocapsid protein).

Conclusions

Prevalence of humoral immunity to SARS-CoV-2 increases if measured in multi-antigen, multi-isotype assays in both serum and saliva. When antibody prevalence is measured only in serum, more than 50% of patients with measurable SARS-CoV-2 antibodies in saliva will not be detected.

Clinical Trial Registration

Netherlands Trial Register, Trial NL8531, URL: https://www.trialregister.nl/trial/8531

Background

The role of children in household transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains uncertain. The COPEDI-CAT project, with more than 120 pediatricians from 71 primary health centers and public and private hospitals, was launched at the end of the first COVID-19 pandemic wave aiming to describe the epidemiological and clinical characteristics of children with COVID-19 in Catalonia (Spain) and investigate the dynamics of household transmission.

Methods

Prospective, observational, multicenter study performed during summer and school periods (1 July-31 October, 2020), in which epidemiological and clinical features, and viral transmission dynamics were analyzed in COVID-19 patients <16 years. A pediatric index case was established when a child was the first individual infected within a household. Secondary cases were defined when another household member tested positive for SARS-CoV-2 before the child. The secondary attack rate (SAR) was calculated, and logistic regression was used to assess associations between transmission risk factors and SARS-CoV-2 infections.

Results

The study included 1040 COVID-19 patients <16 years. Almost half (47.2%) were asymptomatic, 10.8% had comorbidities, and 2.6% required hospitalization. No deaths were reported. Viral transmission was common among household members (62.3%). More than 70% (756/1040) of pediatric cases were secondary to an adult, whereas 7.7% (80/1040) were index cases. The SAR was significantly lower in households with COVID-19 pediatric index cases during the school period relative to summer (p=0.02), and when compared to adults (p=0.006) (figure). No individual or environmental risk factors associated with the SAR were identified.

Conclusions

Children are unlikely to cause household COVID-19 clusters or be major drivers of the pandemic even if attending school. Interventions aimed at children are expected to have a small impact on reducing SARS-CoV-2 transmission.

Clinical Trial Registration

no clinical trial registration