US health officials have given the final OK to Pfizer's COVID-19 vaccine for children as young as 5.

The director of the Centers for Disease Control and Prevention gave the go-ahead Tuesday night.

The announcement came only hours after a CDC advisory panel unanimously decided Pfizer’s shots should be given to children ages 5 to 11.

It's expected that the first doses to kids will be given on Wednesday.

Pfizer has already shipped millions of doses to states, doctors' offices, and pharmacies. And pediatricians are getting ready to put shots into little arms.

The special kid shots contain just a third of the dose given to teens and adults.

Answers to 25 common COVID-19 vaccine questions

Vaccinations for COVID-19 began being administered in the U.S. on Dec. 14, 2020. The quick rollout came a little more than a year after the virus was first identified in November 2019. The impressive speed with which vaccines were developed has also left a lot of people with a lot of questions. The questions range from the practical—how will I get vaccinated?—to the scientific—how do these vaccines even work?

Keep reading to discover answers to 25 common COVID-19 vaccine questions.