Kids can develop other rare problems after an initial coronavirus infection, including heart inflammation or a condition known as a multisystem inflammatory syndrome.
That involves fever and inflammation affecting different body parts, among other possible symptoms. Affected kids generally need to be hospitalised, but most recover.
The surge in Covid-19 delta variant cases has some doctors worrying about the potential for higher numbers of children being at risk for long Covid-19 infection.
Because of the persistent symptoms, the American Academy of Pediatrics has recommended follow-up doctor visits after children recover from an initial coronavirus infection.