Dr. Francis Collins, director of the National Institutes of Health, said he expects children ages 5 to 11 in the United States to become eligible for COVID-19 vaccination toward the end of the year.
"Keep in mind, kids are not just scaled down adults -- they have different immune systems and metabolisms. You really have to do the careful trials to make sure you got the dose right and there aren't any surprises," Collins told ABC News' George Stephanopoulos in an interview Tuesday on "Good Morning America."
"Realistically," he added, "I don't think we're going to see approval for kids under 12 until late in 2021."
NIH director talks about full FDA approval for Pfizer vaccine
Dr. Francis Collins discusses how news of the Pfizer COVID-19 vaccine receiving full approval from the U.S. Food and Drug Administration might affect vaccination rates across the country.
Collins also said there is “no reason to be too confident” that the country has hit its peak and that case numbers will start to come down.
"When I look at the data, it's still going up awfully steeply. More than 150,000 cases a day and that number keeps growing; hospitalizations [at] 95,000; deaths now averaging a 1,000 a day," he noted. "Florida, Louisiana, Mississippi, Alabama -- there's just a world of hurt going on there with so many unvaccinated people and hospitals really struggling to try to manage all the really sick people who are coming to their emergency rooms."