COVID-19, like any disease, is certainly not nice. But it does seem to come with a few small mercies – one of the biggest of which became apparent at the very beginning of the pandemic. As the virus swept across the world, it started to look like children, and in particular young children, could shake it off pretty handily compared to their grown-up peers.

While that is undoubtedly good news for the billions of parents across the globe worried about their kids going back to school as a fresh new variant sweeps the country, it does have some disadvantages. With so few children getting sick, research instead mostly focused on COVID-19 in adults: vaccines and life-saving treatments were rolled out for over-18s only, and studies on things like the disease’s typical presentation and risk profiles were often confined to adult cases only.

A new study, published in the journal JAMA Network Open, aims to fix that. Researchers followed more than 10,300 children at 41 emergency departments across 10 countries – all with the goal of figuring out what severe COVID looks like in children.

“There is a perception that COVID-19 is only a very mild infection in children,” explained Professor Stuart Dalziel, study co-author and Cure Kids Chair of Child Health Research, University of Auckland. “However, as the pandemic has progressed, we are seeing greater numbers of children being infected and presenting to hospital worldwide. Unfortunately, for some of these children, COVID-19 results in severe disease.”

At the beginning of the pandemic, children under 18 made up fewer than one in 20 cases of COVID-19 – and even that was probably an overestimate, the paper explains, “because of testing capacity and the generally mild, or even asymptomatic, nature of the disease in children.”

Now, however, COVID in children is surging – in the US, under 18s account for one in six cases, and record numbers of children are being admitted to hospitals with the virus.

That makes understanding the disease in children imperative, explained study co-lead Dr Stephen Freedman, a pediatrician and professor at the Cumming School of Medicine, University of Calgary, Canada.

“There are no specific evidence-based treatments and therapies for children at this time,” Freedman said, “and detailed research data describing outcomes in young people with COVID-19 has been lacking, so this study offers important insights that we believe will be helpful into front-line care providers treating children with COVID-19.”

Happily, the study mostly turned up good news. Out of more than 3,200 children across the world who visited hospital emergency departments and tested positive for COVID, only around one in 30 ended up experiencing severe outcomes – things like neurologic or respiratory problems, or heart complications – over the following two weeks.

“Fortunately, the risk of developing severe disease in children with COVID-19 discharged from the emergency department is very low,” said study co-lead Dr Todd Florin, director of research in emergency medicine at Ann & Robert H. Lurie Children’s Hospital of Chicago and associate professor of pediatrics at Northwestern University Feinberg School of Medicine. “Our findings can provide reassurance to parents and clinicians for children well enough to be managed in the community, while also providing important insights on which children may be at particular risk for severe outcomes.”

And another piece of good news: while the researchers did identify several important risk factors for severe outcomes in children – “older age (5 to 18 years), having a pre-existing chronic condition and symptom duration” were the main three, Freedman noted – there were some results that proved surprising: asthma, previously suggested as a risk factor for severe outcomes, could not be confirmed as a link, and very young infants proved no more likely than others to experience severe outcomes.

“With emergency departments across the world seeing an influx of patients due to the COVID-19 pandemic and stressing capacity, this study will help address the surge by providing an estimate of the risk among pediatric COVID-19 patients screened in emergency departments,” said Dr. Nathan Kuppermann, chair of Emergency Medicine at University of California Davis Medical Center and co-lead of the study. “It will help emergency physicians triage pediatric patients more efficiently by knowing who has risk factors for severe outcomes and focus advanced level care to those who do.”