Pfizer: COVID-19 Vaccine Is Safe and Effective in Children Ages 5 to 11

elementary school children return to in-person classes

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Pfizer on September 28 announced that it had submitted vaccine efficacy data on children ages 5-11 to the FDA for emergency use authorization.

Key Takeaways

  • Pfizer released new data on the safety and efficacy of its COVID-19 vaccine in young children and said it will apply for FDA authorization.
  • The latest data for children ages 5 to 11 is based on one-third of the dosage given to adults.
  • Experts say pediatric vaccinations will be essential in fighting increased hospitalizations among children.

Pfizer on Monday released new data showing that its COVID-19 vaccines are safe and effective in children between the ages of 5 to 11.

The company said it will be submitting results to the Food and Drug administration (FDA) “with urgency,” and health experts expect an authorization for this age group in late October.

Currently, Pfizer’s vaccine is authorized for emergency use for children aged 12 to 15, and fully approved for people aged 16 and older under the brand name Comirnaty. 

Judith Flores, MD, a pediatrician and a fellow at the American Academy of Pediatrics (AAP) and the New York Academy of Medicine, says that the potential for vaccine rollouts in children aged 5 and above is hugely important for parents, doctors, and teachers, who have so far been worried about how to take care of unvaccinated little ones.

“It's going to mean a great deal to all of us, those of us who take care of the children as physicians and caregivers,” Flores tells Verywell. “It's going to be a big game changer.”

Pfizer Proposed a Lower Dose for Children

Pfizer’s latest data come from a Phase 2/3 trial with 2,268 children ranging from 6 months old to 11 years old. In the study, Pfizer used a two-dose regimen of 10 micrograms per dose, a third of the dosage given to adults.

Ensuring that the vaccine dosage is tailored to the immune system of a child is essential in establishing a safe and effective vaccine, Flores says.

“[Children] have a more robust immunological system. They can mount antibody responses that older people cannot,” Flores says. “So you want to make sure that you get the right response without having a reaction that's more than what you might expect.”

Too high of a dose could result in adverse reactions like high fevers, she adds.

Balancing the vaccine’s ability to fight off the virus with its potential to overwork the immune system is sometimes referred to as the Goldilocks effect, in which scientists find out how to make the product “not too hot, not too cold,” she adds.

Jonathan Baktari, MD, CEO of, says that the reason for giving a smaller vaccine dose to children is comparable to why pharmacies carry children’s Tylenol in addition to the full-strength formula. 

“These are smaller human beings, and technically, their immune systems may be unusually robust compared to an older adult,” Baktari tells Verywell.

He also stresses the importance of balancing efficacy with side effects.

“You don't want a dose that's effective; you want the smallest dose,” Baktari says. “Because the smallest dose, we know in vaccine medicine, generally has the lowest side effect profile.”

Adolescents and COVID Vaccination

More than 10 million 12- to 17-year-olds have been fully vaccinated against COVID-19, according to the Centers for Disease Control and Prevention (CDC). The agency notes that vaccination coverage among teenagers is lower than in older groups. As of September 20, 42% of people aged 12 to 15 are fully vaccinated, while 50.3% of those aged 16 to 17 are fully vaccinated. 

What About Children Younger Than 5?

Data on the vaccine’s effect on the 6-months-and-older age groups should be released in the last quarter of the year, according to Pfizer. These results will be further split into two cohorts: 6 months to 2 years, and 2 years to 5 years.

Baktari expects Pfizer will apply for authorization for the younger groups in late October with a potential greenlight in late December. Whether or not the company will decide to ask for the same or a smaller dose for these groups is unknown, he adds.

Some countries, like Cuba, have started vaccinating as young as 2 years old against COVID-19.

Will Parents Be Willing to Vaccinate Their Kids?

In her work as a pediatrician, Flores says she hears a mix of opinions of whether or not parents want to vaccinate their children against COVID-19. Some people are eager for the vaccines, while others are hesitant about potential side effects.

Some rare side effects of the mRNA vaccines, like heart inflammation called myocarditis, may be more common in younger age groups. Studies have shown that these risks remain rare from vaccination but more likely from coronavirus infection. Knowledge of potential risks helps pediatricians diagnose and treat patients if they develop risky conditions, Flores says.

Rising pediatric COVID-19 cases, the push to get kids back to school, and vaccine mandates may all play a role in encouraging parents to vaccinate their children, she adds.

As of September 16, children represented more than 15% of all COVID-19 cases, according to the American Academy of Pediatrics. Pediatric cases also accounted for between 1.6% to 4.2% of hospitalizations among states reporting data.

“People need to be able to ask all their questions, to [voice] their concerns, but ultimately, the only way out of this pandemic is going to be to have people vaccinated,” Flores says. 

What This Means For You

Pfizer is applying to have its vaccine authorized for children between the ages of 5 to 11. Health experts expect an FDA authorization in late October.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. COVID Data Tracker: Demographic Characteristics of People Receiving COVID-19 Vaccinations in the United States. September 20, 2021.

  2. American Academy of Pediatrics. Children and COVID-19: state-level data report. September 16, 2021.

By Claire Wolters
Claire Wolters is a staff reporter covering health news for Verywell. She is most passionate about stories that cover real issues and spark change.