A team of researchers led by experts in Britain, Austria and Spain looked at the outcomes of nearly 600 children under 18 infected with the novel coronavirus and found that only a quarter had pre-existing medical conditions. 

This is in sharp contrast to adults, among whom the vast majority of patients have underlying health problems. 

The team found that more than 60 percent of COVID-19 positive children required hospital treatment, and that 8 percent needed intensive care.

Of the 582 children studied, just four died.

On the other hand, more than 90 children, or 16 percent, showed no symptoms at all. 

Marc Tebruegge, from University College London's Great Ormond Street Institute of Child Health, said that while the results shouldn't be extrapolated for the general population, they were nevertheless reassuring.

"The case fatality cohort was very low and it is likely to be substantially lower still, given many children with mild disease would not have been brought to medical attention and therefore not included in this study," he said.

"Overall, the vast majority of children and young people experience only mild disease," added Tebruegge, lead author of the study published in The Lancet Child & Adolescent Health journal. 

"Nevertheless a notable number of children do develop severe disease and require intensive care support, and this should be accounted for when planning and prioritizing healthcare resources as the pandemic progresses."

The most common symptom among children in the study was fever (65 percent), followed by upper respiratory tract infection (54 percent) while 25 percent had pneumonia. 

Age is known to be a key risk factor for COVID-19 patients and children have been far less severely affected than adults since the pandemic's outset. 

But the study found a small number of children infected with additional respiratory viruses at the same time as COVID-19, and these were more than three times more likely to require intensive care than those with COVID-19 alone. 

"This could have important implications for the upcoming winter season, when cold and flu infections will be more common," said paper author Begona Santiago-Garcia from Spain's University Hospital Gregorio.