Pfizer says it has begun a mid-to-late-stage study of its antiviral Covid-19 pill for non-hospitalised children aged 6-17 years who are at high risk of developing severe illness, reports Reuters.

The drugmaker plans to enroll 140 children in the study across two groups of 6- to 17-year-olds, with one group including those at least 40 kilogrammes in weight and the other weighing between 20 kgs and 40 kgs.