The Food and Drug Administration on Monday authorized a third dose of Pfizer-BioNTech’s COVID-19 vaccine for children ages 12 to 15, as well as a third dose for children as young as 5 with immune deficiencies. The latest booster authorization comes as health care systems report record hospitalizations among children amid a coronavirus surge driven by the highly transmissible omicron variant. During the week of Dec. 22 to Dec. 28, an average of 378 children age 17 and under were admitted per day to hospitals with the coronavirus, a 66% increase from the week before, the Centers for Disease Control and Prevention reported last Thursday. The booster dose is the same strength as the dose approved in the primary series. A booster dose was previously authorized by the FDA for emergency use for those 16 years of age and older.