WASHINGTON (CBS News) — The CDC issued formal recommendations Tuesday for children as young as 5 years old to get vaccinated against COVID-19, clearing the final regulatory hurdle for younger kids to start receiving Pfizer’s vaccine this week.

“Together, with science leading the charge, we have taken another important step forward in our nation’s fight against the virus that causes COVID-19,” CDC Director Dr. Rochelle Walensky said in a statement.  “We know millions of parents are eager to get their children vaccinated and with this decision, we now have recommended that about 28 million children receive a COVID-19 vaccine.”

The White House says millions of vials of Pfizer’s lower-dose vaccine formulated for younger children have already begun shipping to health care providers following the Food and Drug Administration’s authorization last week.