Risk of Hospitalization, severe disease, and mortality due to COVID-19 and PIMS-TS in children with SARS-CoV-2 infection in Germany (preprint)

Background: Although children and adolescents have a lower burden of SARS-CoV-2-associated disease as compared to adults, assessing absolute risk among children remains difficult due to a high rate of undetected cases. However, without more accurate case numbers, reliable risk analyses are impossible. Methods: We combine data from three sources - a national seroprevalence study (the SARS-CoV-2 KIDS study), the German statutory notification system and a nationwide registry on children and adolescents hospitalized with either SARS-CoV-2 or Pediatric Inflammatory Multisystem Syndrome (PIMS-TS) - in order to provide reliable estimates on childrens hospitalization, intensive care admission and death due to COVID-19 and PIMS-TS. Results: While the overall hospitalization rate associated with SARS-CoV-2 infection was 35.9 per 10,000 children, ICU admission rate was 1.7 per 10,000 and case fatality was 0.09 per 10,000. Children without comorbidities were found to be significantly less likely to suffer from a severe or fatal disease course. The lowest risk was observed in children aged 5-11 without comorbidities. In this group, the ICU admission rate was 0.2 per 10,000 and case fatality could not be calculated, due to an absence of cases. The overall PIMS-TS rate was 1 per 4,000 SARS-CoV-2 infections, the majority being children without comorbidities. Conclusion: Overall, the SARS-CoV-2-associated burden of a severe disease course or death in children and adolescents is low. This seems particularly the case for 5-11-year-old children without comorbidities. By contrast, PIMS-TS plays a major role in overall disease burden among all pediatric age groups.

SARS-CoV-2 Antibodies in Children: A One-Year Seroprevalence Study From June 2020 to May 2021 in Germany (preprint)

Background: Investigating the role of children in the COVID-19 pandemic is pivotal to prevent the virus spreading. In most cases, children infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) develop non-specific symptoms or are asymptomatic. Therefore, the infection rate among this age group remains unclear. Seroprevalence studies, including clinical questionnaires, may contribute to our understanding of the time course and clinical manifestations of SARS-CoV-2 infections.Methods: SARS-CoV-2-KIDS is a longitudinal, hospital-based, multicentre study in Germany on the seroprevalence of anti-SARS-CoV-2 immunoglobulin G, as determined by an Enzyme-Linked Immunosorbent Assay in children (aged ≤17 years). A study-specific questionnaire provided additional information on clinical aspects.Findings: This analysis included 10,358 participants recruited from June 2020 to May 2021. The estimated anti-SARS-CoV-2 seroprevalence increased from 2·0% (95% confidence interval (95% CI) 1·6, 2·5) to 10·8% (95% CI 8·7, 12·9) in March 2021, without major change afterwards and was higher in children with migrant background (on average 6·6% vs. 2·8%). In the pandemic early stages, children under three years were 3·5 (95% CI 2·2, 5·6) times more likely to be seropositive than older children, with the levels equalising in later observations. History of self-reported respiratory tract infections or pneumonia was associated with seropositivity (OR 1·8 (95% CI 1·4, 2·3); 2·7 (95% CI 1·7, 4·1)).Interpretation: The majority of children in Germany do not have detectable SARS-CoV-2 IgG. To some extent, this may reflect the effect of differing containment measures implemented in the federal states. Detection levels might have been greater in certain age groups or migrant background. Lifting containment measurements is likely to cause a general increase in respiratory tract infections, which already pose a challenge to paediatric medical care during regular winter seasons. This challenge might become critical with additional infections caused by SARS-CoV-2.Funding: Funding Information: German Federal Ministry of Education and Research.Declaration of Interests: Authors have no conflicts of interest to declare.Ethics Approval Statement: Ethics committees of each study centre independently approved the study protocol. All parents/guardians gave written informed consent and children assented to the participation when appropriate for their age.