The World Health Organisation's top vaccines expert says that immunising children against the coronavirus is not a "high priority" given the extremely limited global supply of vaccines.

Dr Kate O'Brien says vaccinating children is not a priority from a WHO perspective, even as increasing numbers of rich countries authorise their COVID-19 shots for teenagers and children.

O'Brien says since children are not typically at risk of getting severely ill or dying from COVID-19, vaccinating them during the pandemic is mostly aimed at stopping transmission, rather than protecting them from disease. Canada, the US and the European Union have all recently approved some COVID-19 vaccines for children age 12 to 15 as they approach their vaccination targets for adults.

WHO director-general Tedros Adhanom Ghebreyesus has previously urged rich countries to donate their COVID-19 shots to poor countries rather than immunise their adolescents and children. Fewer than 1 per cent of COVID-19 vaccines administered globally have been used in poor countries.

O'Brien adds that it's not necessary to vaccinate children before sending them back to school if the adults in contact with them were immunised.