WASHINGTON (Xinhua) -- When children have mild symptoms of COVID-19, they are likely to have the disease for a long time. But experts say it is not clear how many children develop the disease for a long time, as there is not enough research on this in this age group, according to a report by CNN on Friday.

Currently, there are no specific tests for long-term infection with Covid-19. Since the beginning of the pandemic, tests have confirmed that nearly 13 million children have been infected with Covid-19, according to the American Academy of Pediatrics.

Studies indicate that between 2 percent and 10 percent of these children will be infected with Covid-19 for a long time, but the number may be higher.