The World Health Organization (WHO) has issued guidance saying children over the age of 12 should wear masks, in line with recommended practice for adults in their country or area.
It admits little is known about how children transmit the virus but cites evidence that teenagers can infect others in the same way as adults.
Children aged five and under should not normally wear masks, the WHO said.
More than 800,000 people have now died with coronavirus worldwide.
At least 23 million cases of infection have been registered, according to Johns Hopkins University, with most of them recorded in the US, Brazil and India.
(Source: BBC News)