Children's Hospital Colorado

COVID-19 Vaccine Approvals: What Comes Next

Patient giving thumbs up after getting vaccine.

This page was updated Nov. 15, 2021. Due to the evolving nature of the pandemic, recommendations can change quickly. Please follow all health and safety guidelines set by your local public health authorities. Reference the Centers for Disease Control and Prevention (CDC) and Colorado Department of Public Health and Environment (CDPHE) for ongoing updates on COVID-19.

When will the COVID-19 vaccines be available for young children? How do we know the vaccines are safe? Our pediatric experts – infectious disease specialists Sean O’Leary, MD, MPHSamuel Dominguez, MD, PhD, and Eric Simões, MD, and Chief Medical Officer David Brumbaugh, MD – break down the latest on our nation’s rollout of several safe and effective vaccines against COVID-19.

The latest on the COVID vaccines 

So far in the U.S., the Food and Drug Administration (FDA) has granted emergency authorization to three vaccines for COVID-19. The Centers for Disease Control and Prevention (CDC) has recommended all three vaccines for certain age groups.  

And the news many families have been waiting for is here: As of November 2, children ages 5 to 11 have joined the ranks of those eligible to receive a COVID-19 vaccine. 

A crucial milestone for kids 

Most children and all teens are now eligible to receive the most effective prevention we have against the coronavirus. Children and teens can get very sick from the virus and its complications, so protecting them is key. 

Results of Pfizer’s clinical trial in kids 5 to 11 

The FDA and CDC signed off on the Pfizer vaccine for 5- to 11-year-olds after a historic clinical trial with more than 4,500 participants. This study demonstrated that a schedule of two 10-microgram doses of the Pfizer vaccine (equivalent to one-third of the dose for older children and adults) given 21 days apart was found to be safe, immunogenic, and efficacious in children 5 to 11 years of age. In other words, the two-thirds of trial participants who received the vaccine reported no serious adverse events and showed robust immune response, and the vaccine was found to be more than 90% effective at preventing COVID-19. The trial findings were presented to the FDA, CDC and published in the New England Journal of Medicine

This newly eligible age group represents 8.6% of the U.S. population and about 12% of Colorado’s population, so there’s real potential to make progress against the pandemic – but it depends on individuals and families to take part and get immunized. 

It’s perfectly natural to have questions, so here at Children’s Hospital Colorado, we’re urging parents and caregivers to learn more about the COVID vaccine for kids from trusted resources and to ask any remaining questions of their child’s pediatrician.

History in the making: How Colorado kids played a part 

Children’s Colorado was the largest study site in the country for Pfizer’s clinical trial investigating the safety and immune response of their COVID vaccine in kids ages 5 to 11. Before the trial began over the summer, families representing approximately 5,000 children expressed interest in joining the trial here. We then reviewed the eligibility of those who expressed interest, and ultimately enrolled 252 participants through our site. 

How the study worked

Each child was randomly assigned to receive either the study vaccine (two-thirds of participants) or a placebo (one-third of participants). They received two injections approximately three weeks apart. Neither the family nor the doctors knew whether the child received the study vaccine or placebo until their follow-up visit six months after the second injection. With the EUA for children 5 and older now in place, trial participants were “unblinded,” and participants who received the placebo were invited to receive the vaccine at Children’s Colorado.

And the study isn’t over. While experts have enough data to determine that the vaccine’s benefits outweigh the risks during this public health emergency, we’ll continue to learn more as this and other clinical trials progress. Over the course of two years, trial participants will have scheduled follow-up study visits and will track any changes in their child’s health in an electronic diary.

This exact process is taking place at study sites across the world.

Hope for the future

The initial clinical trial results were impressive, and they paved the way for the EUA for children ages 5 through 11 in November 2021.

“The COVID vaccine for children 5 to 11 is now available in large part thanks to the wonderful Colorado children who volunteered to be part of the trial,” says Dr. Simoes, the principal investigator of the trial at Children’s Colorado. “These 252 children understood the importance of the vaccine. I thank them for their contribution to science, history and humanity.” 

How effective are the vaccines? 

Clinical trials showed the mRNA-based Pfizer and Moderna vaccines to be more than 90% effective. The Johnson & Johnson vaccine was shown to be 66% effective worldwide, although that figure increased to 72% in the U.S. 

The term “effective” refers to the vaccines’ ability to prevent all symptomatic infections. But even in cases where someone got sick, in clinical trials all three vaccines were still overwhelmingly effective against severe infection, including hospitalization and death. That’s still the case in the real world, where millions of people are now fully immunized.  

With vaccines deployed widely, evidence of their effectiveness is mounting, including for the pediatric population. One recent study found that the Pfizer-BioNTech mRNA vaccine was 93% effective in preventing hospitalization for COVID-19 in adolescents and teens — even as the highly contagious delta variant became the dominant strain in the U.S. 

An impressive rollout 

State and federal agencies are working as quickly as possible to safely deliver vaccines to anyone who wants one, and the pace so far has been impressive: As of November 9, the CDC reported that 58.5% of people in the U.S.  were fully vaccinated. That’s zero to over half in 10 months. Now that the EUA for 5- to 11-year-olds has gone through, we expect to see another uptick. In Colorado, the governor’s goal is to vaccinate 50% of the state’s children in this newly eligible age group by the new year. 

How many kids have been vaccinated? 

According to the CDC and American Academy of Pediatrics, more than 12.4 million 12- to 17-year-olds are fully vaccinated as of November 10, or about 50% of this age group. When you include adolescents who have received at least one dose of the vaccine, that number grows to 14.7 million, or about 59% of 12- to 17-year-olds. 

Vaccinations for younger groups are off to a strong start, according to early reports. Here in Colorado, more than 11,300 children between 5 and 12 received their first dose by November 8, including more than 5,000 who visited CDPHE clinics hosted by Children’s Colorado. A few days later, by the end of the day on November 10, more than 900,000 children between 5 and 12 years old nationwide had received their first dose of the COVID-19 vaccine, according to numbers released by the White House. 

Will other COVID-19 vaccines be authorized for kids? 

Early data from Moderna’s clinical trials in kids ages 12 to 17 have shown promising results, which means Moderna’s mRNA vaccine may also be authorized for use in everyone ages 12 and older soon.

When will kids younger than 5 be vaccinated?

The emergency use authorization for Pfizer’s vaccine in kids 5 and older is a huge step forward. But younger kids still need to wait.

Children under 5 are not likely to get the vaccine for several more months. Medical experts are projecting that the earliest younger kids will become eligible is early- to mid-2022, though it’s difficult to predict.  

Why it’s taking longer for kids 

It’s important that COVID vaccines are studied in kids before using them widely.  But things are moving. Clinical trials for children 6 months and older are still in progress. Drs. Brumbaugh and O’Leary encourage families to be patient while waiting for a safe and effective vaccine for even younger kids. While we wait, parents should make sure that the whole family is taking precautions to prevent COVID-19, including masks and social distancing, and receives a flu shot sooner than later.

What about reports of adverse events? 

With any vaccination effort, especially one on this scale, experts expect reports of adverse events. In fact, public health agencies proactively track reports of vaccine side effects using their internal data and surveillance systems and by soliciting reports from members of the public. When they detect a trend or similarities in the types of health events being reported, they investigate and run statistical calculations to determine whether there’s a true association between an adverse event and a vaccine, or if the number of events is expected relative to the size of the population.

Heart issues and the mRNA vaccines 

There have been rare instances of myocarditis and pericarditis, swelling of the heart muscle and the sac around the heart, in people under 30 who received mRNA vaccines, including pediatric patients. The CDC is evaluating reports of myocarditis closely to understand any association between the vaccine and heart issues. From what we know so far, these side effects remain extremely rare, and research shows that risks of heart inflammation after contracting COVID-19 are much higher than after receiving the vaccine.  

“It’s understandable to have concerns about these reports, but keep in mind that myocarditis can be caused by a number of viral infections, including COVID itself,” says Dr. Brumbaugh. The CDC continues to recommend the mRNA vaccines given the risk of long-term complications from the coronavirus itself.

“The good news is that our systems worked – we found this side effect,” says Dr. Dominguez. “We've been able to quantify it and understand the risks around it. But overall, these vaccines have proven to be remarkably safe in the general public.”

Learn how vaccine safety systems work.

Are these COVID-19 vaccines safe?

Vaccines have historically been remarkably safe and effective, and our experts believe all three currently available vaccines — along with any other vaccines that might be authorized — are no different.

That’s because, although the process has been accelerated, no corners are being cut. All three vaccines went through every single step of the vast, rigorous and complex process required to understand the safety and effectiveness of any new vaccine.

"This didn’t just happen in a year. This work is built on decades of remarkable progress in the development of vaccines,” says Dr. O’Leary. “I think we have many reasons to trust the process."

That goes not just for COVID-19 vaccines, but for the many other vaccines available. Dr. O’Leary notes that general vaccination rates for kids have recently declined, potentially because families are avoiding healthcare providers’ offices due to the pandemic.

That would be a mistake, Dr. O’Leary says. Vaccines are the single best way to prevent disease: Kids need them to stay safe. That’s especially true this year, when COVID-19 has the potential to complicate other diseases in ways that are difficult to anticipate — including influenza. Dr. O’Leary urges families to make sure kids get their flu shot as soon as they become available.

As for the COVID-19 vaccines, it may be a while longer before they’re available for all ages. And the pandemic isn’t over. The highly contagious delta variant is spreading fast and causing increased case counts and hospitalizations, particularly among the unvaccinated. Until you are fully vaccinated (2 weeks after your last dose) and even once you are fully vaccinated, there’s still every reason to take precautions like social distancing and wearing masks—especially indoors.

There’s a light at the end of the tunnel, but reaching it depends on all Americans who can get vaccinated following through with the lifesaving immunizations.

“I’m still optimistic,” Dr. O’Leary says.  “Early on, it was pretty clear to those of us in infectious disease that the only way out of this pandemic would be with vaccines. What I've observed in the last 18 months is nothing short of miraculous. We were hoping for vaccines that were 50% effective, and we got vaccines that were more than 90% effective at preventing infection and even better at preventing hospitalization and death.  

“These vaccines are a gift.” 

Trustworthy sources on the COVID-19 vaccines


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