Merijn W. Bijlsma (Netherlands)

Emma Children’s Hospital, Amsterdam University Medical Centre Paediatrics

Merijn Bijlsma is a paediatrician and researcher. His training in paediatrics and epidemiology was at Amsterdam UMC in the Netherlands. After completing a PhD focused on the epidemiology of bacterial meningitis at the University of Amsterdam, he continued his research with a focus of long-term outcome after meningitis and neonatal Group B streptococcal disease. He combines national surveillance data, with large clinical cohorts and bacterial genetic sequencing, with the aim of improving diagnostics and prevention.

Author Of 1 Presentation

Conference Calendar

SYSTEMIC AND MUCOSAL HUMORAL IMMUNITY AGAINST SARS-COV-2 IN CHILDREN

Date

Thu, 12.05.2022

Session Time

10:00 - 11:30

Session Type

Oral Presentations Session

Session Name

0640 - ORAL PRESENTATION SESSION 05: COVID-19 Session II (ID 88)

Room

BANQUETING HALL

Presenter

Maya W. Keuning (Netherlands)

Lecture Time

10:32 - 10:42

Abstract

Abstract

Backgrounds:

Patients produce systemic and mucosal antibodies after SARS-CoV-2 infection. In the context of ongoing public health measures and vaccination programs, it is crucial to explore practical methods to monitor this humoral immunity. Following our earlier findings of heterogeneity in serum and saliva SARS-CoV-2 antibodies in 2020, we now describe antibody prevalence in serum and saliva of children one year after the beginning of the pandemic and explore associations.

Methods

We assessed SARS-CoV-2 antibody prevalence in serum and saliva of 223 children attending medical services in the Netherlands (irrespective of COVID-19 exposure) from May - October 2021. The cohort included vaccinated and unvaccinated children (< 18 years old) and was compared to 517 unvaccinated children from the April - October 2020 cohort. We measured SARS-CoV-2 spike- and nucleocapsid-specific IgG prevalence in serum and saliva.

Results:

Our cohort contained 75% unvaccinated children, 18% with a PCR-proven history of COVID-19, and a 1:1 male-female ratio. Antibody prevalence increased from 3-4% in both serum and saliva in 2020 to 38% (95% CI 31 - 45) in serum and 31% (95% CI 25 - 38) in saliva in 2021. Paired analysis (figure 1) showed positive titers in both serum and saliva in 53/196 (27%). Prevalence of spike and nucleocapsid-specific IgG was significantly lower in saliva compared to serum (P<0.05). Girls showed a higher prevalence of saliva antibodies as compared to boys (OR 2.26 corrected for age, vaccination status, comorbidity, positive PCR).

espid 2022 mw keuning - sarscov2 systemic and mucosal antibodies figure 1.jpg

Conclusions/Learning Points:

SARS-CoV-2 antibody prevalence in children increased in serum and saliva between 2020 and 2021 in the Netherlands. We observed lower SARS-CoV-2 antibody prevalence in saliva compared to serum, which should be taken into account when evaluating humoral immunity.

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