Children and teenagers are less likely than adults to develop severe COVID-19 or die from the disease.

This is according to the world’s largest study of hospital patients with COVID-19. Obesity, Black ethnicity and being under one month old are factors that increased the risk of a child being admitted into intensive care with the condition, the report reveals.

By using data from the majority of COVID-19 hospital cases we can reveal just how rarely the disease is serious or fatal for children. Professor Peter Openshaw

The findings also identify new symptoms of a severe inflammation syndrome that significantly increases the risk of children with COVID-19 needing intensive care. Researchers are calling for the WHO’s definition of this syndrome – Multisystem Inflammatory Syndrome in Children (MIS-C) – to be updated to help doctors identify more children with the condition and improve their treatment.

The team, led by researchers from the Universities of Edinburgh and Liverpool, Imperial College London and the Royal Hospital for Children, Glasgow, recruited 651 children and young people aged 19 years or younger who had been admitted to hospital with COVID-19.

Largest hospital study

The study is led by ISARIC4C – a global group of clinicians working to prevent death from respiratory disease – and involved 138 hospitals across England, Wales and Scotland. The ISARIC4C COVID-19 study includes two thirds of all people admitted to hospital with the disease.  

The findings suggest that it is rare for young people to end up in hospital with COVID-19. They make up less than one per cent of participants in the ISARIC study. The research is published today in the British Medical Journal.

Dr Olivia Swann, lead author and Clinical Lecturer in Paediatric Infectious Diseases at the University of Edinburgh, said: “Researchers often want to call attention to large numbers of patients in their studies, however, we want to highlight that children made up only a fraction of a percent of all COVID-19 admissions across the UK in our study and that severe disease was rare.”

Professor Peter Openshaw, from the National Heart & Lung Institute at Imperial, said: “By using data from the majority of COVID-19 hospital cases we can reveal just how rarely the disease is serious or fatal for children. This should be reassuring, but will also need to be closely monitored as children return to school.”

Risk factors

The typical age of hospitalised children was five years old. Some 42 per cent of patients had at least one other condition, the most common including neurological conditions and asthma.

The number of children and young people who died from Covid-19 was relatively low – six in total out of the 651 – when compared with adult deaths.  Three children who died were newborn babies born with other severe health problems. The other three children were aged 15 to 18 years old and also had profound health issues.

Some 18 per cent of hospitalised children and young people were admitted to intensive care. Experts say children most at risk of needing intensive care were those under one month old and those aged 10 to 14 years old. Like adults, obesity and Black ethnicity were also found to be risk factors.

Insights into inflammatory syndrome

The study also identified 52 patients who had MIS-C, an inflammatory syndrome linked to COVID-19. The researchers found that these children were five times more likely to be admitted to intensive care.

The symptoms usually seen in those with MIS-C include conjunctivitis, a rash, or gastrointestinal problems such as abdominal pain, vomiting and diarrhea. The study also found new COVID-19 symptoms in children with MIS-C. These include headaches, tiredness, muscle aches and a sore throat.

The study also found that the number of platelets – a component of the blood involved in clotting – was much lower in the blood of children with MIS-C than in those without the condition. The combination of symptoms and low platelets may be important in identifying children with MIS-C who may become more unwell, experts say.

Dr Louisa Pollock, Consultant in Paediatric Infectious Disease at the Royal Hospital for Children, Glasgow, said: “Parents should be reassured by this study which confirms very few children were seriously affected by COVID-19. As children return to school, and over the winter months, it is important we continue to monitor COVID-19 in children.”

This research was funded by UK Research and Innovation (UKRI) and by the Department of Health and Social Care through the National Institute for Health Research (NIHR) as part of the UK Government’s COVID-19 rapid research response.  

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‘Clinical characteristics of children and young people hospitalised with covid-19 in the United Kingdom: prospective observational cohort study’ by Olivia V Swann et al. is published in the British Medical Journal.

Based on a press release by the University of Edinburgh.