WATCH: Fauci testifies on COVID-19 response in Senate hearing

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, testified before the Senate Health, Education, Labor and Pensions committee on Thursday about ongoing efforts against COVID-19.

Watch Fauci’s remarks in the player above.

Fauci’s appearance follows U.S. health officials on Tuesday giving the final signoff to Pfizer’s kid-size COVID-19 shot, a milestone that opens a major expansion of the nation’s vaccination campaign to children as young as 5.

The Food and Drug Administration already authorized the shots for children ages 5 to 11 — doses just a third of the amount given to teens and adults. But the Centers for Disease Control and Prevention formally recommends who should receive FDA-cleared vaccines.

The announcement by CDC director Dr. Rochelle Walensky came only hours after an advisory panel unanimously decided Pfizer’s shots should be opened to the 28 million youngsters in that age group.

The decision marks the first opportunity for Americans under 12 to get the powerful protection of any COVID-19 vaccine.