Parents of 11-year-olds: Here's what experts say you should do about the COVID-19 vaccine

Tammy Kolbe has been eager to get her daughter vaccinated against COVID-19 since the start of the pandemic. But when a vaccine was authorized for children 5 to 11, she paused to weigh her options.

The Food and Drug Administration allowed a 10-microgram dose of the Pfizer-BioNTech vaccine for this age group, one-third the 30-microgram dose being administered to Americans 12 and older.

Kolbe’s 11-year-old daughter, Leisl, is turning 12 in February. They discussed waiting until her 12th birthday to get vaccinated but rising COVID-19 cases in their community of Warren, Vermont, makes Kolbe wonder if it’s worth the risk.

“We’ve been anxiously awaiting the vaccine for kids but it’s unclear to me, even after talking to my pediatrician, whether or not the small dose she might receive is appropriate because she’s almost 12,” said Kolbe, 51. “(It’s) a hard decision where you have imperfect information, and I’ve been weighing the risks versus the imperfect information.”

Ultimately, she decided to make an appointment to get her daughter vaccinated as soon as possible with the lower dose for younger children.

Many parents and guardians like Kolbe are weighing the risks and benefits of getting their 11-year-old vaccinated now, or waiting until their child’s 12th birthday when they can get the 30-microgram dose authorized for adolescents.

But health experts say the lower dose is likely to give the children – whether they’re 11 or 12 –  the same protection against COVID-19 as the higher one. They urge parents and guardians to get their children vaccinated as soon as possible, especially as the winter holidays bring family gatherings that increase the risk of coronavirus transmission.

“Delaying vaccination for a birthday to roll around doesn’t seem smart,” Dr. Susan Coffin, a physician at the Children’s Hospital of Philadelphia’s division of infectious diseases, said during a media briefing Wednesday. “Any week that we delay vaccination, we’re increasing the risk that our child might get an infection, might bring infection home or might contribute to the spread of infection amongst their friends.”

Like adolescents and adults, the lower-dose vaccine is given to children ages 5 to 11 in two shots, administered three weeks apart.

The only difference in the children's Pfizer-BioNTech vaccine – besides the dosage –  is the addition of one chemical called tri-sucrose. Tri-sucrose already is used in several other vaccines and makes it easier to dilute and remain stable in a refrigerator for up to 10 weeks, a Pfizer executive said.

The Centers for Disease Control and Prevention said vaccination should be based on a child’s age the day of vaccination – not size or weight. If a child turns 12 in between the two-dose regimen, the agency recommends they get the 30-microgram dose as a 12-year-old even if they received 10 micrograms for their first dose.  

However, the FDA's emergency use authorization allows children who will turn from 11 to 12 between their first and second dose to receive two jabs of the 10-microgram dose if the 30-microgram dose isn’t available during their second visit.

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“They do not need to repeat the dose and this is not considered an error per the EUA,” the CDC said. “As opposed to many medications, vaccine dosages are based on age and not size or weight.”

Vaccine dosages are based on age because the immune system works differently at different ages, said Dr. Nathan Rabinovitch, pediatric allergist and immunologist at National Jewish Health. The immune system of a child is not as mature as the immune system of an adult.

“It’s not like a medication that is going to have to go into the bloodstream and be distributed throughout the body,” he said. “It’s more about how robust the immune system is and that’s a function of age and not of how big you are.”

Dr. Alejandra Gurtman, vice president of Vaccine Clinical Research and Development at Pfizer, said at a CDC committee meeting Tuesday seven children turned 12 during the clinical trial. They all received the 10 microgram dose for both shots and mounted a strong immune response against COVID-19.

“The study was designed knowing that this could happen,” she said about the birthdays.

Health experts say the lower dose is just as effective in children as the higher dose in adults and adolescents. Pfizer’s clinical trials show the two-dose, 10-microgram regimen was found to be nearly 91% effective in preventing COVID-19 among children 5 to 11.

More vaccine or a higher dose doesn't necessarily translate to more protection, Rabinovitch said. Once a child reaches a certain threshold of intended immunity, they've reached their full potential of protection and won't be more protected with more vaccine. 

"If you look at the neutralizing antibodies, it's not a linear response," he said. "What happens is that it goes up and then it plateaus at a certain number." 

Phase 3 clinical data presented last year showed the vaccine was 95% effective in adults. But new research that has not yet been peer-reviewed suggests efficacy may be closer to 84% after six months.

Seeking a higher dose for your tween has no clear clinical benefit and may even produce more severe side effects than necessary, said Dr. Sean O’Leary, a pediatric infectious disease doctor at Children’s Hospital Colorado and professor of pediatrics at the University of Colorado School of Medicine.

The trials showed children experienced the same types of mostly minor side effects seen in adolescents and young adults. They included sore arms, fatigue, headaches, muscle pain, chills and low-grade fevers that lasted a day or two.

“They compared those side effects to 16- to 25-year-olds and it appeared that the rate of things like fever and chills was less in the 5- to 11-year olds than what we saw in the older adolescents and young adults,” he said. “If I were a parent, I would not go looking for a higher dose because it’s ‘better protection.’”

Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT. 

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