Maya W. Keuning (Netherlands)
Amsterdam University Medical Centre, University of Amsterdam Pediatric infectious diseasesPresenter of 1 Presentation
SALIVA SARS-COV-2 ANTIBODY PREVALENCE IN CHILDREN - COVID KIDS STUDY (ID 522)
Abstract
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