SARS-CoV-2 in children

This section is aimed at assisting public health professionals and is based on an ongoing rapid review of the latest evidence.

Incidence in children

(Latest update 14 June 2022)

Throughout the pandemic, children have constituted the lowest proportion of notified COVID-19 cases  [1]. During the early part of the pandemic, case notification rates were lowest for children, although studies have since suggested this could have been a result of low case ascertainment due to higher rates of asymptomatic and mild cases in children, and lower testing rates, rather than a decreased susceptibility (see Susceptibility) [2]. With increasing adult vaccination coverage, children now constitute a relatively larger proportion of notified cases. The spread of more transmissible variants, with increased immune escape capability, has resulted in higher transmission in all age groups, including children, resulting in increases in 14-day case notification rates [1,3]. 

Throughout the various waves of the pandemic, differences in 14-day case notification rates have been observed between age groups of children, where the lowest rates among children have broadly been observed in the youngest age groups, with higher rates in older adolescent ages groups, which sometimes mirror or exceed those of young adults [1,4]. These differences may be a result of age-group-related differences in testing rates, clinical manifestations, vaccination coverage, social mixing, and biological susceptibility.

For more information on case notification rates: 

Susceptibility

(Latest update 14 June 2022)

The relatively low numbers of reported cases of SARS-CoV-2 infection in children throughout the pandemic led to the hypothesis that children may be less susceptible to infection than adults[5]. However, conclusions in published studies have been inconsistent: lower notifications in children could be the result of a combination of factors, including low case ascertainment (due to mild and asymptomatic cases), lower biological susceptibility, and less social mixing [2]. 

Severity

(Latest update 14 June 2022)

Children often experience mild or asymptomatic COVID-19 [6]. The risk of onset of severe disease resulting in hospitalisation or death is lower than in adults [7]. During the two-month period (3 August 2020 to 3 October 2021) of one study from 10 EU countries, there were approximately 117 hospitalisations (of which eight required ICU admission and respiratory support) for every 10 000 reported symptomatic paediatric cases [8]. 

The majority of children hospitalised due to COVID-19 do not have comorbidities, but comorbidities also increase the risk of severe disease, hospitalisation, and death in children [8]. Children made up an increasing proportion of hospitalisations as adult vaccination coverage increased (and thus rates of adult hospitalisation decreased), and child hospitalisations have also increased during periods of high transmission. However, rates of hospitalisation of notified SARS-CoV-2 cases among children remain low [9]. 

The low proportion of severe COVID-19 in children compared to adults contrasts with infections caused by many other respiratory viruses for which severe disease is more commonly observed in children.  It seems likely that a combination of different factors result in decreased protection in adults (including ACE2 receptor expression, declining immune function with age, higher prevalence of comorbidities associated with severe COVID-19) and increased protection for children (including less social mixing, differences in immunity) [10]. In addition, evidence also shows that vaccination effectively reduces severity of COVID-19 disease among adults and children [4,11].

The impact and prevalence of post-COVID-19 condition (‘long COVID’) in children in the EU is unclear due to the lack of high-quality pan-European studies and a clear case definition [12]. Several studies have reported post-COVID-19 condition in children [12,13]. Children who experience severe COVID-19 are more likely to experience long-term symptoms, and there may be an increased risk in children older than 10 years and those with certain underlying medical conditions [13,14]. In a large Danish nationwide cohort study of 37 522 children aged 0-17 years with RT-PCR-confirmed SARS-CoV-2 infection (and a control group of 78 037 children without history of SARS-CoV-2 infection), the most common prolonged symptoms among schoolchildren with a history of SARS-CoV-2 infection were loss of smell, loss of taste, fatigue, respiratory problems, dizziness, muscle weakness, and chest pain [15].

Inflammatory multisystem syndrome, known as paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) [16] or multisystem inflammatory syndrome in children (MIS-C) [17], is a rare severe outcome of COVID-19 in children [13]. PIMS-TS/MIS-C shares common clinical features with other paediatric inflammatory syndromes, such as Kawasaki disease, toxic shock syndrome, and macrophage activation syndrome. Children with PIMS-TS/MIS-C often present four to six weeks after infection, with a wide clinical spectrum, including Kawasaki disease-like symptoms, life-threatening shock, and milder forms of illness such as persistent fever, inflammation, and gastrointestinal manifestations [1]. The median age for cases of PIMS-TS/MIS-C is eight years [18,19]. The condition generally occurs in children who are often previously healthy and experience mild or asymptomatic initial SARS-CoV-2 infection [13,19]. Most children with critical illness due to PIMS-TS/MIS-C have a favourable outcome and recover with intensive care support and appropriate treatment [1].

Uncertainties remain regarding the impact of highly transmissible variants such as the Omicron variant of concern (VOC) on post-COVID-19 condition, MIS-C [3], and the severity of COVID-19 infections in children.

More information about post COVID-19 condition and PIMS-TS is available on ECDC’s Clinical Characteristics latest evidence page.

Considerations for schools

(Latest update 14 June 2022)

Children can contract and spread SARS-CoV-2, but it has generally been concluded that transmission in schools follows, rather than drives, community transmission [20-23]. Evidence on the effectiveness of school closures on reducing transmission is limited, as these were often implemented at the same time as wide societal restrictions [24]. There is some evidence that the closure of secondary schools has more impact on reducing community transmission than primary schools, which is in line with the observed rates of transmission in older versus younger age groups of children [1]. Disaggregated evidence on the impact of individual infection control measures is lacking, but the implementation of multi-layered mitigation strategies in schools, including contact reduction, non-pharmaceutical interventions, and surveillance can enable schools to remain open in situations of high community transmission [25,26], although further observational and experimental studies are needed.

ECDC’s technical reports on COVID-19 in children and the role of school settings in transmission.

Vaccination

(Latest update 14 June 2022)

Vaccination is recommended in 12–17-year-olds in all EU/EEA countries, with some now also recommending booster doses for this age group [4]. The European Medicines Agency (EMA) has approved vaccination for 6-11-year-olds (Spikevax, Cominarty). 

Available vaccine effectiveness data for adolescents from the period in which Delta was the dominant variant show a very high level of protection against infection, symptomatic disease, and severe disease [4]. Vaccine-induced protection of adults against severe disease caused by the Omicron VOC is also strong, but it has thus far been concluded that current vaccines are less effective at preventing transmission, suggesting that vaccinating children is unlikely to be effective in reducing transmission in the general population [27].  

With the circulation of variants such as Omicron and the lower risk of severe outcomes of COVID-19 in children without comorbidities, the direct benefits of vaccination for children are therefore likely to be lower than for adults [28]. However, vaccination remains beneficial for children at higher risk of severe disease, and can protect against post COVID-19 condition and PIMS-TS/MIS-C [4].

For up-to-date data on COVID-19 vaccination of children and adolescents in the EU/EEA:

ECDC technical reports on COVID-19 vaccination in children:

For information on COVID-19 vaccine safety:

Conclusion

(Latest update 14 June 2022)

For children, the risk of infection and severe disease from SARS-CoV-2 is low. There is, however, an increased risk of severe disease in children with comorbidities. Vaccination is of particular importance for children at higher risk of severe disease. The implementation of multi-layered mitigation measures in schools, particularly during periods of high community transmission, is important to ensure the safe operation of schools and limit transmission in children.

Most currently available data in peer-reviewed studies and systematic reviews are from before the widespread circulation of the Delta and Omicron VOCs, limiting the certainty of the conclusions that can be drawn.