Pfizer’s coronavirus vaccine could become available for children ages 5 to 11 as soon as next week, and some New York pediatricians say they’re expecting appointment slots to fill up quickly.

The Food and Drug Administration authorized the shot for these youngsters on Friday after an advisory committee voted in favor of the move earlier in the week. But child-sized doses — about a third the size of what’s given to adults — cannot be distributed to doctors’ offices until after the Centers for Disease Control and Prevention holds a hearing next week to sign off.

Matteo Trisolini, the director of operations at South Slope Pediatrics in Brooklyn, said he started getting calls from parents asking about when the vaccine will be available ahead of its authorization. His practice is one of hundreds across New York that have pre-ordered more than 380,000 child-sized doses of the Pfizer vaccine so far.

“We're asking our patients to be patient with us and we'll get them all through the door,” Trisolini said. “We have about 1,400 children just in our practice that will become eligible [for the vaccine]. If you imagine a third of that population calling us Monday to schedule the appointment as soon as possible, then you understand what might happen.”

Pediatricians have been preparing for the vaccination rush, including some who were not previously offering a COVID-19 vaccine to adolescents, who have been eligible since May. Dealing with the logistics of storing the vaccine at ultra-cold temperatures and administering it without letting any go to waste can create a particular challenge for smaller practices, said Dr. Warren Seigel, chair of the New York State chapter of the American Academy of Pediatrics.

For starters, he said, if a practice is vaccinating adolescents or adults as well as young children, they will need two separate places to store the vaccines so as not to mix them up. Along with the pediatric shot carrying smaller amounts of the drug, the doses also come in their own special vials. Practices will also need space to observe children for 15 minutes once they get vaccinated to ensure they don’t have an allergic reaction.

South Slope Pediatrics might stay open extra hours, including weekends, to have the capacity to vaccinate children without interrupting regular medical appointments. “We can't just stop wellness visits or newborn appointments to accommodate the vaccines,” Trisolini said.

He said South Slope Pediatrics began offering the Moderna vaccine for adults months ago in an effort to get a better sense of what the process would look like. He noted that it was hard to know in advance how many doses health officials would deliver in each shipment or what the delivery schedule would be.

“As soon as we get the first shipment [of the Pfizer vaccine], and we get an idea of what they're going to do, then we can modify our ordering,” he said.

Complicating matters further, his doctor’s office doesn’t have the special freezer necessary to store the Pfizer vials and keep them ultra-cold until their expiration date. They can also be stored using regular refrigeration — but only for up to two weeks.

State officials have been working with the New York chapter of the American Academy of Pediatrics for weeks to help pediatricians prepare, Gov. Kathy Hochul said at a press conference Wednesday. While primary care doctors were not a major part of New York’s COVID-19 vaccination strategy early in the adult rollout, officials said they would be pivotal in inoculating young children. Dr. Emily Lutterloh, the state’s director of epidemiology, is leading the effort.

“We know parents want to be able to talk to their child’s pediatrician and get their kids vaccinated where they get their other medical care,” Lutterloh said at Wednesday’s press conference alongside Hochul. “That means we need pediatricians and other doctors who see children to talk to parents and encourage those who are eligible to get the vaccine and to give the vaccine in their office.”

While the shots will also be available at some pharmacies and schools, Hochul administration has no current plans to reopen large vaccination sites. The state is reaching out to individual school districts to find out what role they want to play, Hochul said. As of Wednesday, 350 districts had committed to host vaccination events, and nearly 390 said they would send information about the shots to parents.

Early demand could vary based on neighborhood vaccination rates. Surveys conducted in New York City and nationally show parents who are inoculated against COVID-19 themselves are far more willing to vaccinate their children under 12.

For now, some pediatricians are still telling eager parents to wait a little longer.

“People are saying, ‘I want to make an appointment and we’re saying, ‘Not yet,’” said Seigel, who chairs the Department of Pediatrics at Coney Island Hospital. “We’re not going to give you an appointment for something we don’t have.”