See some of the first 5- to 11-year-old kids get their COVID-19 vaccines

After a unanimous vote in favor of the vaccine, an independent committee of experts advised the Centers for Disease Control and Prevention to recommend a lower dose of the vaccine for the youngest age group yet.

The child-sized dose was found to be 91% effective at reducing the risk of symptomatic illness in 5- to 11-year-olds in clinical trials.

Most kids will get vaccinated in a pediatrician's office or hospital, rather than at the mass vaccination sites used to get shots to adults as quickly as possible, Insider previously reported.

While many centers are still waiting for their child-tailored shots — with lower doses and smaller needles — Children's National Hospital in Washington, DC, had received a batch as soon as it was authorized this week.

They started vaccinating pediatric patients straight away, and shared photos of the occasion.

When it looked like the shot would be authorized for young kids soon, Children's National Hospital began reaching out to the families of high-risk pediatric patients to reserve appointments in advance, according to a press release.

Medical conditions like asthma, obesity, diabetes, congenital heart disease, and some neurologic disorders can make certain kids more likely to experience severe COVID-19 infections, so they'll be prioritized to get their shots.

The kids' vaccine will be administered in two shots just like the adult version, but with smaller doses. While adults and teenagers got two 30-microgram doses, 5- to 11-year-olds will receive just 10 micrograms of Pfizer's vaccine in each shot.

Doctors and nurses are using smaller needles on kids than on adults, too.

Fifteen million doses and syringes made for children were distributed nationwide ahead of the authorization, and Pfizer will continue to issue up to 50 million more in the coming weeks, the Wall Street Journal reported.

Pfizer's clinical trial for 5- to 11-year-olds included 2,268 kids split into groups that received two different doses of the vaccine.

The researchers decided a low-dose shot would be just as successful at preventing COVID-19 with fewer side effects, which could help alleviate some anxieties for parents and children, a principal investigator previously told Insider.

The most common side effects from the shot reported in clinical trials were pain at the injection site, fatigue, and headache.

However, those symptoms are pretty mild compared to the pain, tenderness, redness, fever, and chills reported by the trial group who got the 30-microgram dose. The two groups produced similar amounts of antibodies, but the side effects were far more severe for the high-dose cohort.

Pfizer reported a swallowed penny and a broken bone among a handful of adverse events that took place during the clinical trial, but none was related to the vaccine.

To help soothe any fears of needles, Children's National had a therapy dog on hand to sit with kids when they got their shots on Wednesday.

Demand for the kid-sized vaccines could outpace supply in the early stages of rollout, as roughly a third of parents of young kids want to get them vaccinated as soon as possible, according to the Kaiser Family Foundation.

The government has purchased enough supply for all eligible children, however; a massive shipment of 15 million shots will reach providers by next week, the White House said.

"Delta has made COVID a pediatric problem," Dr. Andrew Pavia, a pediatric infectious disease specialist, told Insider in October. "They've often heard that because kids don't die at the rates that adults do, that it's not a big deal. And that was sort of true in 2020. With Delta, it's not true."

Scientists have concluded that children are at least as likely as adults to be infected with the coronavirus, and they can also be a source of exposure for adults working in schools and caregivers at home.

The rollout of COVID-19 vaccines to school-aged children represents the light at the end of the tunnel for some families.

"This is me jumping for literal joy about my unprotected daughter getting vaccinated today," Beth Blauer wrote on Twitter Wednesday. "Thank you to all scientists, reviewers, and doctors that made this possible."

"It's amazing to think that a little more than a year ago, we were wiping down groceries with wipes, and now we have vaccines! For adults and kids!!" tweeted Josh Sternberg, another parent and executive editor of Morning Brew, a publication in which Insider has a majority stake.