Pfizer-BioNTech COVID-19 vaccine for children ages 5-11 has been approved. The first shipment of the Pfizer-BioNTech COVID-19 vaccine for children ages 5-11 has arrived at Cook Children's. We've received enough doses to vaccinate more than 3,000 children. Cook Children's will begin vaccination clinics on Saturday, November 6 for Cook Children's patients with an existing MyCookChildren's account.