Canada has authorised Moderna COVID-19 vaccine for use in children from the age of 12 to 17. The country had earlier approved Pfizer-BioNTech COVID-19 vaccine for the same age group. More than 76% of adolescents aged 12-17 years have received at least one COVID-19 vaccine dose and 63.57% have been fully vaccinated as of August 21, regulator Health Canada said.