European data: Understanding the burden of COVID-19 in children

In order to make evidence-based decisions on the need to vaccinate children against coronavirus disease (COVID-19) as well as deciding on ways to mitigate transmission risks e.g. in school settings, it is essential to understand the actual burden of COVID-19 among children [1].

In their rapid communication ‘COVID-19 trends and severity among symptomatic children aged 0–17 years in 10 European Union countries, 3 August 2020 to 3 October 2021’, Bundle et al. report on the burden and severity of notified symptomatic COVID-19 cases among children in the European Union (EU). They estimate the risks of severe outcomes among the 820,404 symptomatic paediatric COVID-19 cases that were reported by 10 EU countries during that period.

The authors observed that since the start of 2021, hospital admission and notifications of COVID-19 among children have been increasing. Pooled weekly case notification and hospitalisation rates increased sharply in all age groups (children as well as adults) from July 2021 onwards.

Among the more than 820,000 notified COVID-19 cases among children from the 10 reporting countries, 9,611 (1.2%) were hospitalised, 640 (0.08% of all cases, 6.7% of hospitalised cases) were admitted to an intensive care unit (ICU) and 84 (0.01%) children died.

Hospitalisation risk highest for youngest
Based on the available data, the youngest age groups (0 to 2 months) carried the highest risk of being hospitalised - with point estimates that decreased with increasing age up to 9 years of age and then increased again with each year from 12 to 17 years. Results for periods coinciding with dominance of the Delta variant were consistent with the full study period, although hospitalisation was more common among children younger than 1 year (14.7% Delta vs 13.1% full period; p < 0.01).

The risk of a severe COVID-19 outcome was higher among children with existing underlying health conditions such as cancer or diabetes. After controlling for age group, reporting country, four time periods [2] and sex, adjusted odds of hospitalisation, ICU admission and death were seven, nine and 27 times higher, respectively, among cases with at least one comorbidity compared with children that had none. However, the vast majority of hospitalised children with COVID-19 (83.7%) had no reported comorbidity. According to the authors, this could demonstrate ‘a potential population-level impact of high levels of community transmission leading to large numbers of hospital admissions among healthy children’.

Very low risk of death or hospitalisation for most children with symptomatic COVID-19
The authors conclude that ‘case notification and hospital admission rates among children rise as overall transmission increases, but [that] most children with symptomatic COVID-19 have a very low risk of death or hospitalisation’. Based on the presented data from the study, for every 10,000 symptomatic paediatric cases, around 117 were hospitalised and eight required ICU admission or respiratory support.

As only 15.2% (range: 1.0–29.0%) of children younger than 18 years in the EU and European Economic Area (EEA) had been fully vaccinated against COVID-19 by the end of November 2021 (week 47), Bundle et al. note that large numbers of unvaccinated children will likely be exposed to the virus during current high COVID-19 incidence in many parts of the EU/EEA which could lead to increases in the absolute numbers of children, both with and without underlying health conditions, that experience severe COVID-19 outcomes.

According to the authors ‘preventive measures to reduce transmission and severe outcomes in children remain critical, as does the submission of timely, complete surveillance data to facilitate assessment of severity following the emergence of new variants’.

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References/notes to editors:
[1] Nick Bundle, Nishi Dave, Anastasia Pharris, Gianfranco Spiteri, Charlotte Deogan, Jonathan E Suk. COVID-19 trends and severity among symptomatic children aged 0–17 years in 10 European Union countries, 3 August 2020 to 3 October 2021
Available from: https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2021.26.50.2101098

This study was undertaken before the detection of the respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant of concern.

Limitations of the study
Data on vaccination status of the children in this study was not available, however, during the study period, vaccines were only approved in the EU for use in children 12–17 years-old. As children are less likely to be symptomatic for COVID-19 than adults, reporting of cases may be biased towards those with severe disease.

[2] Namely weeks 32/2020 to 53/2020 as ‘pre-vaccine period’, weeks 1/2021 to 21/2021  when the Alpha (B.1.1.7) variant was dominant, weeks 22/2021 to 27/2021 when both Alpha and Delta variants were co-circulating and weeks 28/2021 to 39/2021 when the Delta variant was dominant.

[3) More articles on COVID-19 and children in our collection: https://www.eurosurveillance.org/content/children--schools-and-covid-19