Centers for Disease Control and Prevention director Rochelle Walensky signed off on allowing Moderna and Pfizer COVID-19 shots for children as young as 6 months old on Saturday.

Why it matters: The shots could be in little arms as early as next week, as most states have already pre-ordered COVID vaccines for children under 5 in anticipation of federal authorization.

• Earlier Saturday, a key CDC advisory committee unanimously voted to support a recommendation for the shots for children.

What they're saying: "Together, with science leading the charge, we have taken another important step forward in our nation’s fight against COVID-19. We know millions of parents and caregivers are eager to get their young children vaccinated, and with today’s decision, they can,” Walensky said, according to the Wall Street Journal.

• In a statement, President Biden praised the "monumental step forward in our nation’s fight against the virus, with virtually every American now eligible for the protections that COVID-19 vaccines provide."
• "For parents all over the country, this is a day of relief and celebration, as the first country to protect our youngest children with COVID-19 vaccines," Biden's statement said.
• The statement also confirmed parents can schedule appointments for their children to be vaccinated beginning next week. "These vaccines are safe, highly effective, and will give parents the peace of mind of knowing their child is protected from the worst outcomes of COVID-19," Biden's statement said.

Zoom in: The shots received emergency use authorization by the FDA on Friday after being considered by an FDA advisory committee earlier in the week. The FDA says the pediatric dose of Moderna COVID-19 coronavirus vaccine may trigger an immune response "slightly more rapidly" than the Pfizer vaccine, while Pfizer might produce a "greater response" after the third dose.

• Pfizer's vaccine was approved as a three-dose series for children 6 months through 4 years old. Each dose is about a 10th of the size of an adult dose and FDA advisers warned this week that parents need to be aware that all three doses are needed to develop a sufficient immune response to fight infection.
• Children would receive the first two doses three weeks apart. The third dose would be delivered at least two months later.
• Moderna's vaccine was approved as a two-dose series for children 6 months through 5 years old. Each dose is about a quarter of the dose given to adults and each would be delivered about four weeks apart.

The big picture: While many parents of the youngest Americans have been anxiously awaiting the chance to get their child vaccinated, it remains unclear how strong uptake of the shot will be.

• The American Academy of Pediatrics estimates 8.2 million, or just more than a third of kids (36%) ages 5 to 11 have gotten at least one shot as of June 8. And 14.8 million U.S. kids ages 12 to 17 (59%) have gotten at least one COVID shot.