Washington – The US Food and Drug Administration has authorised two Covid-19 vaccines for children aged 5 and under. It authorised Pfizer-BioNTech’s, vaccine for children aged 6 months to 4 years, and Moderna’s shot for those 6 months to 17 years. Pfizer’s is already authorised for those over the age of 5. While many parents in the United States are eager to vaccinate their children, it is unclear how strong the demand will be for the shots. The Pfizer-BioNTech vaccine was authorised for children aged 5 to 11 in October, but only about 29% of that group is so far fully vaccinated federal data shows.