Children and young people appear to be over 50% less likely to catch coronavirus than adults but evidence remains weak on how likely children are to transmit it to others, according to researchers.
They said the findings provided further evidence on child susceptibility to Covid-19 and would be important for ministers making decisions about school reopening and easing lockdown restrictions.
“Our findings show children and young people appear 56% less likely to contract Covid-19 from infected others”
In the largest study of its kind, researchers carried out a systematic review and meta-analysis of over 6,000 studies, to try and understand how likely it was for children to catch Covid-19 and pass it on.
They found 18 studies with useful data – nine were contact-tracing studies, eight were population-screening studies and one was a systematic review of small household cluster contact-screening.
Their analysis showed that children and young people – aged under 18-20 years – had 56% lower odds of catching coronavirus from an infected person, compared with adults – aged over 20.
However, the researchers – from the UK, Australia and the Netherlands – acknowledged they did not have sufficient data to examine whether children under 12 differed to teenagers in susceptibility.
In addition, while children appeared less likely to catch the virus from others, once they were infected, the researchers said they remained uncertain about how likely children were to pass it on.
They concluded that their findings implied that children were likely to play a lesser role in coronavirus transmission at a population level, because fewer children were likely to be infected in the first place.
“This new evidence will help us better understand the possible effect of school reopening on transmission”
The study involved researchers from University College London (UCL), the London School of Hygiene and Tropical Medicine, Cambridge University, Exeter University, Sydney University and the Dutch National Institute for Public Health and the Environment. It is currently awaiting peer-review and will be formally be published at a later date.
Lead author Professor Russell Viner, from UCL, said: “This is the first comprehensive study to carefully review and summarise what we do and do not know about [child] susceptibility and transmission.
“Our findings show children and young people appear 56% less likely to contract Covid-19 from infected others,” he noted.
“This supports the view that children are likely to play a smaller role in transmitting the virus and proliferating the pandemic, although considerable uncertainty remains.”
Professor Viner added: “It is well known that children and young people make up only a very small percent of confirmed clinical cases of Covid-19, in most countries, including the UK.”
Study co-author Dr Rosalind Eggo, from the London School of Hygiene and Tropical Medicine, said the findings suggested that children and young people were at lower risk of infection than adults.
“This new evidence will help us better understand the possible effect of school reopening on transmission in schools and in the community,” she said.
An alert was sent to clinicians in April to warn of a potential Covid-19-related inflammatory syndrome that could be emerging in children in the UK.
The warning said that “there has been an apparent rise in the number of children of all ages presenting with a multisystem inflammatory state requiring intensive care across London and also in other regions of the UK”.
It added there was “growing concern” that this was a Covid-19-related inflammatory syndrome emerging in children in the country, or that it could be another unidentified infectious pathogen.