Less than 10 per cent of globally reported COVID-19 cases and less than 0.2 per cent of deaths have been people under the age of 20, but more research is still needed on the risk of severe disease and death among children and adolescents, the chief of the World Health Organisation (WHO) said.

"We know that this virus can kill children, but that children tend to have a milder infection and there are very few severe cases and deaths from COVID-19 among children and adolescents," said WHO Director-General Tedros Adhanom Ghebreyesus at a press briefing on Tuesday, Xinhua news agency reported.