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US Centers for Disease Control and Prevention Director Dr. Rochelle Walensky said Tuesday evening she was endorsing a recommendation to vaccinate children ages 5-11 against Covid-19, clearing the way for immediate vaccination of the youngest age group yet in the United States.

“CDC now expands vaccine recommendations to about 28 million children in the United States in this age group and allows providers to begin vaccinating them as soon as possible,” the agency 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,” Walensky said. Shortly after she issued her recommendation, staff at Hartford HealthCare in Connecticut vaccinated a half-dozen boys and girls, streaming the event on Facebook.

“As a mom, I encourage parents with questions to talk to their pediatrician, school nurse or local pharmacist to learn more about the vaccine and the importance of getting their children vaccinated,” Walensky said.

Earlier Tuesday, CDC’s independent vaccine advisers voted 14-0 in favor of the child-sized doses of vaccine for the younger kids.

Members of CDC’s Advisory Committee on Immunization Practices spent an unusually long time speaking in support of the vaccine before they voted. “We have one more vaccine that saves lives of children. And that we should be very confident to deploy it to the maximum to do what it is meant to do without significant concerns of serious adverse effects,” said Dr. Sarah Long, a professor of pediatrics at Drexel University College of Medicine in Philadelphia.

“As you’ve heard, we all have a lot of enthusiasm for this vaccine in this age group,” Dr. Beth Bell, a clinical professor of global health at the University of Washington, said after the vote.

“But we also understand that parents have legitimate concerns and legitimate questions and that our vote is a way of telling the American public that based on our expertise and the information that we have, we’re all very enthusiastic,” Bell added.

“We were all talking about how we’re getting our kids and our grandkids vaccinated. But I think another point that we made to the American public is that we do understand that people have legitimate concerns and that they have lots of questions. We really encourage people to ask their providers, to visit the CDC website, to talk to their friends, their parents and do what they need to do to feel comfortable with their decision,” Bell added.

President Joe Biden weighed in, calling the decision a turning point in the battle against the pandemic.

“It will allow parents to end months of anxious worrying about their kids, and reduce the extent to which children spread the virus to others. It is a major step forward for our nation in our fight to defeat the virus,” Biden said in a statement.

“Over the last several weeks, my Administration has been working hard to be prepared for this moment: we are ready to act. We have already secured enough vaccine supply for every child in America, and over the past weekend, we began the process of packing and shipping out millions of pediatric vaccine doses. These doses — specially designed for these younger children — have started to arrive at thousands of locations across the country.”

The White House has said the vaccination program will hit full speed next week.

“A vaccine for children age 5 to 11 will allow us to build on the extraordinary progress we’ve made over the last nine months. Already, more than 78 percent of Americans age 12 and older have gotten at least one shot, including millions of teenagers — and the vaccines have proven to be incredibly safe and effective,” Biden said.

The CDC says 745 children and teenagers under 18 have died of Covid-19.

Walensky said it’s also important to continue vaccinating adults.

Children now make up a disproportionate number of new Covid-19 cases, according to a report published Monday by the American Academy of Pediatrics – accounting for a quarter of all the new cases last week.

The US Food and Drug Administration authorized Pfizer’s vaccine for this younger age group on Friday, giving the company the distinction of having the first emergency use authorization for a Covid-19 shot for younger kids in the United States. The FDA said the benefits of the vaccine outweigh the risk to children.

Pfizer says its clinical trial showed the vaccine provides 90.7% protection against symptomatic disease among this age group – at one-third the dose of what people 12 years and older get. The company hopes the smaller dose will reduce any potential side effects.

Data the company presented to the meeting indicated that the younger children who tried out the vaccine were far less likely to suffer systemic side effects such as fever than the older children, teens and young adults were.

Pfizer’s Dr. Alejandra Gurtman told ACIP that fever was far less common among these younger kids than among older people – with 6.5% of younger children experiencing fever in clinical trials of the vaccine, compared to 17.2% of 16-25-year-olds.

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Millions of doses of the vaccine are already being shipped from the company’s facilities to distribution centers across the country, ready to go out to pharmacies and pediatricians’ offices.

The American Academy of Pediatrics, which represents pediatricians, welcomed the decision.

“Vaccinating children will protect children’s health and allow them to fully engage in all of the activities that are so important to their health and development. Parents can enjoy greater peace of mind gathering with family members this winter and sending their children to school, sports and other events that were paused during the height of the pandemic,” it said in a statement after the ACIP vote.

CNN’s Jen Christensen contributed to this report.