Pfizer reported Monday that three smaller-sized doses of its COVID-19 vaccine were safe and effective at preventing symptomatic illness in children under the age of 5. Pfizer’s announcement came as it prepared to submit a request for emergency use of its pediatric vaccine for U.S. children as young as 6 months old. Approval could come after the FDA convenes a panel of independent vaccine experts on June 15, when the agency will also consider Moderna’s application for emergency use of its vaccine in young children.