Ari Blank got a comforting hand-squeeze from his mom in May as he was vaccinated against COVID-19 in Bloomfield Hills, Mich. This week, the Food and Drug Administration authorized the use of Pfizer's vaccine in even younger kids — ages 5 to 11.

Ari Blank got a comforting hand-squeeze from his mom in May as he was vaccinated against COVID-19 in Bloomfield Hills, Mich. This week, the Food and Drug Administration authorized the use of Pfizer's vaccine in even younger kids — ages 5 to 11. / AFP via Getty Images

The Food and Drug Administration has authorized a Pfizer-BioNTech COVID-19 vaccine for children ages 5 to 11. This lower-dose formulation of the companies' adult vaccine was found to be safe and 90.7% effective in preventing COVID-19.

The agency acted Friday after a panel of independent scientists advising the FDA strongly supported the authorization on Tuesday. The FDA says the emergency use authorization is based on a study of approximately 4,700 children ages 5 to 11.

"As a mother and a physician, I know that parents, caregivers, school staff, and children have been waiting for today's authorization. Vaccinating younger children against COVID-19 will bring us closer to returning to a sense of normalcy," said the FDA's acting commissioner, Dr. Janet Woodcock, in a statement.

She went on to assure parents that the agency had rigorously evaluated the data and "this vaccine meets our high standards."

The next step in the process before the vaccine can be released to pediatricians, pharmacies and other distribution points will be a meeting of an advisory panel to the Centers for Disease Control and Prevention next Tuesday.

Depending on the outcome of that committee's deliberations, the CDC's director, Dr. Rochelle Walensky, would then have the final say on whether the vaccine can be used and in what circumstances.

Once Walensky weighs in, children in this age group could, conceivably, begin to receive their first shot in early November.

A dose of the Pfizer vaccine for young children contains one-third the amount of active ingredient used in the vaccine for those 12 years old and up. Children would receive a second dose 21 days or more after their first shot.

The vaccine also differs from the existing formulation that teens and adults have been getting in that it can be stored in a refrigerator for up to 10 weeks — making it easier for private medical offices, schools and other locations to keep and administer the vaccine.

Children ages 5 to 11 have accounted for approximately 9% of reported COVID-19 cases in the U.S. overall and currently account for approximately 40% of pediatric COVID-19 cases, according to Dr. Doran Fink, clinical deputy director of the FDA's Division of Vaccines and Related Products Applications. Currently, he says, the case rate of COVID-19 among children ages 5 to 11 is "near the highest" of any age group.

Unvaccinated children who get COVID-19 can develop a serious complication called multisystem inflammatory syndrome, or MIS-C. More than 5,000 children have gotten the condition so far, according to Dr. Fiona Havers, a medical officer at the CDC who presented data this week to the FDA committee.

In deliberations at Tuesday's advisory panel, scientists and clinicians discussed the risks of side effects from the vaccine. Myocarditis and pericarditis — which can occur after viral infections, including COVID-19 — have been seen as rare side effects after vaccination with the two mRNA vaccines, Pfizer and Moderna, especially among young men.

In the Pfizer-BioNTech study submitted to the FDA, there were no cases of myocarditis in the children studied. However, given that the highest risk for these rare side effects is among teen males, the agency assessed the risks and benefits of vaccinating younger children and concluded that the benefits of preventing hospitalization from COVID-19 outweigh the possible risks of the side effects.

During Tuesday's advisory panel discussion, Capt. Amanda Cohn, a physician and medical officer with the CDC and also a voting member of the FDA committee, said that vaccinating young children against COVID-19 can save lives and keep kids out of the hospital.

"We have incredible safety systems in place to monitor for the potential for myocarditis in this age group, and we can respond quickly," she said. "To me, the question is pretty clear. We don't want children to be dying of COVID, even if it is far fewer children than adults, and we don't want them in the ICU."

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Tags: children and vaccines  Moderna vaccine  Pfizer vaccine  multi inflammatory syndrome  coronavirus pandemic  Johnson & Johnson  Treatments  Series: The Coronavirus Crisis