Pediatricians say some parents are eager to vaccinate their kids, with others asking questions

And parents are coming at them with a lot of questions: When can my child come in to get their vaccine? And what are the side effects?

But before administering vaccine, doctors' offices are waiting for the US Centers for Disease Control and Prevention to give the green light. And, of course, they're waiting for the vaccines themselves.

On Friday, the US Food and Drug Administration authorized two 10-microgram doses of the Pfizer/BioNTech coronavirus vaccine to be administered three weeks apart to children ages 5 to 11. Vaccine maker Pfizer and its partner BioNTech said they will begin shipping the pediatric doses of their vaccine immediately.

"Everybody is very excited -- even my kids," Dr. Ilan Shapiro, medical director of health education and wellness for a federally qualified health clinic at AltaMed in California, told CNN on Friday. His children are ages 6 and 9.

Some 28 million children ages 5 to 11 are eligible for the vaccine, and pediatricians and pharmacies are already preparing to administer their shots, once the CDC recommends doing so. On Tuesday, the CDC's Advisory Committee on Immunization Practices is meeting to discuss the vaccines.

As the nation approaches this historic moment in the Covid-19 pandemic, vaccinating the youngest age group yet against Covid-19, pediatricians' offices report the mood among parents is a mix of eagerness and hesitancy.

'This is what I expected'

For Dr. Christina Johns, senior medical adviser at PM Pediatrics and a pediatrician in Annapolis, Maryland, the mix of moods is what she expected.

"Two-thirds of families are excited for the vaccine -- these families want to be first in line and will be signing their children up once available," Johns wrote in an email to CNN about her patients' families.

"One-third of families, on the other hand, are still hesitant and have questions," she added. "This is what I expected and falls in line with data from other medical groups."

Dr. Ania Wajnberg, director of clinical antibody testing at The Mount Sinai Hospital, has seen a similar mix of moods around getting children vaccinated.

"I think probably about a third are dying to do this. I fall into that group," said Wajnberg, a mother of two children between the ages of 5 and 11. She added that the pandemic has been difficult for children since many have been social distancing from friends and loved ones, and some families view getting vaccinated as a way to bring children a new level of freedom as well as some protection against Covid-19.

"Then I think there's about a third that are nervous and want to wait a little," Wajnberg said. "So, they might feel more comfortable after some weeks or months when hundreds of thousands or millions of kids have gotten it. And then of course there may be a group that wants to wait a bit longer."

The questions some parents have

The majority of US parents in one nationwide survey reported that they will not get their younger children vaccinated right away.

The survey, published Thursday from the Kaiser Family Foundation, found that among parents of children ages 5 to 11, only 27% said they are eager to vaccinate their children against the virus as soon as a vaccine becomes available. A third say they will wait a while to see how the vaccine is working and 30% said they will definitely not get the vaccine for their 5-11-year-olds.

About 76% of those surveyed said that they were "very" or "somewhat" concerned about long-term side effects, while 71% worried about serious side effects. A growing number of people also seemed to believe the myth that vaccines could impact fertility. About 66% of people surveyed said they were "very" or "somewhat" concerned that the vaccine may negatively impact their child's future fertility.

Those are some of the same concerns that parents have shared with Shapiro, the pediatrician and father based in California.

Most of his patients' parents have asked: "'What are the side effects?' 'What do we know about fertility?' And the third one, 'If I want to have it, when can I get it?' Those are the main three questions," Shapiro said.

In its announcement about authorizing the vaccine for children, the FDA noted that the vaccine's safety was studied in about 3,100 children ages 5 through 11 who received the vaccine. No serious side effects have been detected in the ongoing study.

Commonly reported side effects in the clinical trial included a sore arm where the shot was administered, redness and swelling, fatigue, headache, muscle or joint pain, chills, fever, swollen lymph nodes, nausea and decreased appetite.

Side effects were generally mild to moderate and occurred within two days after vaccination, and most went away within one to two days, the FDA reported. More children reported side effects after the second dose than after the first dose.

"And of course you have the question, 'What's happening with fertility?' Right now we have a lot of good information that that's completely not happening. There's no reason why parents should be afraid of infertility in kids," Shapiro said.

"And a lot of parents actually do want to vaccinate," he added. "But the question is when? Do I need to use another day of school? Do we need to lose another day of work? There's a lot of other complicated questions."

Shapiro said that he hopes children get vaccinated quickly in order for the United States to avoid a serious surge in Covid-19 cases this upcoming winter.

"We're closing on the window that we can make a huge difference for December, January and February. That's my main concern right now," Shapiro said.

"Right now, if we do not strongly do something, I'm extremely worried of what's going to happen in December," he said. "We know it takes six weeks to make a difference. So then if I get vaccinated November 1, my body will be defending me completely by December 15. So the window is now -- for adults and for kids."

The Pfizer/BioNTech vaccine is administered as two doses three weeks apart, and in general, people are considered fully vaccinated two weeks after their second dose.

'The biggest challenge right now is the unknown'

Pfizer's vaccine for the younger children is not only reformulated at one-third the dose, but re-packaged -- with a new orange top, so it will be difficult to mix up with the adult vaccine.

The Biden administration has secured enough vaccine supply to vaccinate the 28 million children ages 5 to 11 who are eligible for vaccination and will help equip more than 25,000 pediatric and primary care offices, hundreds of community health centers and rural health clinics as well as tens of thousands of pharmacies to administer the shots, according to the White House.

The vaccine that Pfizer tested in children is the same as the one used in adults, but a smaller dose -- 10 micrograms, rather than 30 micrograms. The vaccine is expected to ship in packages of 100 doses, which is much smaller than the packages of 1,170 doses used for the adult vaccines.

Hypothetically, providers could start giving Covid-19 shots to 5-to-11-year-olds right now under the FDA's emergency use authorization and before the CDC's recommendation to do so -- something that occurred when vaccines were authorized for older kids -- but that still would depend on which providers' orders for vaccine are filled first and how quickly those providers receive shipments of the doses.

"The main difference for this rollout is that pediatrician offices are likely to be the places to administer vaccines," Johns wrote in her email to CNN, but she added that the vaccine doses allocated to pediatricians' offices still need to be shipped -- and the timeline for that remains somewhat unclear.

"The biggest challenge right now is the unknown. We do not have information on when we can expect to receive shipments and the supply amounts, which can make setting the dates and times more difficult," Johns said.

"We also want to be sensitive to the fact that these are children in school, so we need to make sure there is minimum loss of instruction time. Our goal is to make the whole process convenient, easy and accessible for families."

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