COVID-19 vaccines for children: timing, side effects and more

Over the last year, a heroic effort has brought about multiple safe and effective vaccines that offer excellent protection against COVID-19. States and the federal government have made considerable progress rolling out these vaccines to help finally end the coronavirus pandemic.

Initially, the vaccines were only available to people age 16 and older. But on May 10, 2021, the Food and Drug Administration issued an emergency use authorization for the Pfizer-BioNTech COVID-19 vaccine for the prevention of coronavirus disease in adolescents 12 to 15 years of age. This was an amendment to the initial EUA that had been issued for the Pfizer vaccines on December 11, 2020, that permitted administration of the vaccine in people age 16 years and older.

Citing data curated by the New York Times, Dr. Lisa Doggett, senior medical director for HGS AxisPoint Health, a care management services company based in Westminster, Colorado, and a newly appointed fellow with American Academy of Family Physicians’ Vaccine Science Fellowship, says that more than “4.5 million people in the U.S between the ages of 12 and 18 years have received at least one dose of the vaccine.”

When kids younger than 12 will be eligible to receive the vaccine is still an open question, she adds. “Clinical trials are underway to assess vaccine effectiveness and safety in kids from age 6 months to 11 years old right now, and results are expected sometime later this year. I’m optimistic that kids in the 5- to 11-year-old age range will gain access to the vaccine this fall, but probably not in time for everyone to be fully vaccinated by the time schools reopen.”

[Read: Abdominal Pain in Kids.]

Why kids came second

Dr. Alex Li, a board-certified pediatrician and internist and deputy chief medical officer of L.A. Care Health Plan, the largest publicly operated health plan in the country, says that many people associate vaccines with childhood. “Most vaccines, such as for chickenpox, measles and so on, are infections that are more deadly and mostly affect children. Additionally, many vaccines are administered during childhood so that kids can develop lifelong immunity. Thus, there’s a perception that vaccines are only for kids,” Li says. One exception is the shingles vaccine.

COVID-19 is different from diseases like the mumps and rubella because the virus has predominately impacted older people.

The Centers for Disease Control and Prevention reports that 8 out of 10 COVID-19 deaths have been in adults age 65 and older in the U.S. That burden of disease is a major reason why adults were prioritized over kids for the COVID-19 vaccine, Li says.

“Although anyone can get infected by the COVID-19 virus, we saw early on in the pandemic that COVID-19 was particularly devastating for older adults, those 65 and older, and for people with chronic health conditions. Most of those who were hospitalized or died were older adults and/or those with chronic health conditions.”

Still, some children have gotten very sick and were hospitalized or died of the disease. Data curated by the American Academy of Pediatrics indicate children represent about 2% of hospitalizations related to COVID-19. As of May 27, a total of 322 children had died of COVID-19, a figure based on data reported by 43 states, New York City, Puerto Rico and Guam.

While the chances that children will get very sick or die of COVID-19 are far less than in older adults and it made sense to initially focus on vaccinating adults, children still need to be protected, says Dr. Octavio Ramilo, chief of infectious diseases at Nationwide Children’s Hospital in Columbus, Ohio. “They deserve to be vaccinated.”

Testing a new technology

Clinical trials “usually start in healthy, immunocompetent adults,” and upon successful completion of those initial trials, additional trials are expanded to “special populations such as children, pregnant people and the immunocompromised,” says Dr. Vidya Mony, a pediatric infectious disease specialist with Santa Clara Valley Medical Center in San Jose, California.

This is the standard approach within the pharmaceutical industry, says Dr. Pamela Zeitlin, a pediatric pulmonologist with National Jewish Health in Denver. “New molecules are tested first in adults and then marched down through adolescence to lower and lower ages. In this case, drug companies could have included some of the older teenagers in their clinical trials, but they started with adults, I think, because the mRNA vaccines are so new.”

Lynne Georgopoulos, a registered nurse and vice president of regulatory strategy at Certara, a drug discovery accelerator headquartered in Princeton, New Jersey, says the first two vaccines that were authorized for use in the U.S. — one made by Pfizer-BioNTech and the other by Moderna — both used this ” novel RNA vaccine platform. Prior to the COVID-19 vaccine, there were no licensed RNA vaccines on the market,” and the limited clinical data made it “difficult to speculate” how children’s responses to the vaccine would compare to that of adults.

Though these mRNA vaccines may seem new, that doesn’t mean they haven’t been rigorously tested, Ramilo notes. “For years, people have been preparing all the tools to apply for this particular virus. A lot of the technology and ideas have been worked on for years. So, it’s not like everything happened out of the blue. There was a lot of background work for many, many years that allowed this to happen.”

Plus, some of the steps along the path to vaccine authorization have been taken in parallel to save time, Ramilo says. “At the same time that they were doing ‘A,’ they were doing a little bit of ‘B’ and ‘C.’ They were not waiting until ‘A’ was completely done to start ‘B.'” This helped condense the timeline while retaining the same safety measures.

“Before vaccinating children, vaccine developers must complete the necessary clinical trials, to demonstrate that the vaccine is safe and effective in children, and the data must then be reviewed by the Food and Drug Administration,” Georgopoulos says. “The dose and design of these trials are based on information learned from studies in adults.”

That evidence has grown, and the FDA has acted accordingly in greenlighting the EUA for the Pfizer vaccine. On May 25, Moderna announced that its trials had proven that the vaccine was safe and effective in children aged 12 to 17, and the FDA is currently reviewing the data. It’s likely that the Moderna vaccine will be authorized for use in children aged 12 and older in the very near future.

So far, the safety of the Pfizer vaccine in kids aged 12 to 15 has been found to be excellent, Doggett says. “There have been very rare reports of possible complications, such as a case of myocarditis (inflammation of the heart muscle) that the CDC is investigating. But the risk of getting infected with COVID-19 is far more than any potential risk from the vaccine.”

When kids younger than 12 will become eligible is not yet clear, but clinical trials in kids aged 6 months to 11 years of age are ongoing. These trials are studying the appropriate dose for younger kids, Zeitlin says. “The size of a six-month old versus a 17-year-old is quite different,” so understanding how to most effectively adjust the dose size for kids of different ages is important.

Ramilo adds that the trials are also looking to test which dose is effective in which age group, but also whether the frequency or severity of vaccine side effects changes with the dose size. “If you give a bigger dose, do you have more fevers or more sore arms or adverse events? And how is the antibody response? It’s about finding the right balance” between developing as many antibodies as possible without triggering an adverse event. You test different doses on small groups of people and look at the data.”

Zeitlin predicts that “6- to 12-year-olds will be eligible by the end of the calendar year. It’s probably too soon to say when six months and older would be available, but it may be a bit longer than that.” The hope is that eventually, a vaccine will be available for everyone from six months of age and up.

[Read: How to Help Kids With Anxiety.]

Staying safe until younger kids are eligible

If your child is younger than 12 and not currently eligible to receive a COVID-19 vaccine, it’s important to keep taking precautions to prevent infection. “We know that fortunately kids, especially younger kids, are at much lower risk of getting sick with COVID-19 than adults. That said, the risk is not zero,” Doggett says.

“The risk in the coming months, and especially with a return to in-person school for most kids this fall, depends greatly on how much we can lower rates of COVID-19 that continue to spread in our communities.” This will be easier in communities where infection rates are low, as kids will have less opportunity to come into contact with the virus and potentially contract it. In communities where rates are higher, the risk to kids is higher too.

“In making decisions about school and activities for my kids, I’ve been following the COVID-19 infection rates in our community, and I consider the risks involved in each situation,” Doggett says.

This means thinking about things like:

— Group size.

— Whether the activity will be held outdoors or indoors.

— Whether others will be wearing masks.

— Whether social distancing can be maintained.

These decisions aren’t always easy to make, she notes, “but as case rates drop, we can feel more comfortable letting our kids, especially once they are fully vaccinated, resume their usual activities.”

[See: Common Childhood Respiratory Diseases.]

Measuring immune response and dosage in children

Kids are different from adults, and their bodies may react differently to medications and vaccines. “It’s important to keep in mind that children are not small adults, and even among children, there can be significant differences in how various age groups — from infants to teenagers — react to vaccines and medications,” Georgopoulos says.

Ramilo adds that because children are growing, the way the body reacts to any medication or vaccine may vary substantially from adults. They metabolize things differently and may need a very different dose.

This is why the vaccine makers are carefully testing the efficacy and safety of their products in progressively younger cohorts of children. “With teenagers, the immune system is closer to that of an adult,” Ramilo says. “But the minute you go down in age groups, we need to be more observant to see if the younger children also react in a similar way.”

Pregnant women and newborns

Another point of note: The Pfizer-BioNTech and Moderna vaccines have been found to be safe and effective in pregnant and breastfeeding women. Research has also indicated that breastfeeding “mothers can pass antibodies to their newborns, which will protect them until they can get the vaccine at six months,” Georgopoulos says.

Vaccinate your children to stop the spread

Doggett says that her two teenage daughters “got vaccinated as soon as they became eligible. They’ve done well with no problems or even side effects, besides a sore arm.”

There are plenty of good reasons to get your child vaccinated now if they’re age 12 or older or as soon as they become eligible. First, some schools may require that students be vaccinated to take part in any in-person lessons. Some colleges are already doing this, and it’s likely that come fall, there will still be a good bit of variation from county to county and even school to school regarding whether classes are conducted in person, remotely or using a hybrid model.

Also, vaccinating kids will help stop the spread throughout the entire community and help us get back to a more normal life. “The best way to stop this pandemic is to achieve herd immunity, and that won’t happen without broad vaccination among all age groups,” Georgopoulos says.

Even as the number of people vaccinated here in the U.S. continues to climb steadily, the race is on against variants that may be more contagious and deadlier even though studies have indicated that the vaccines are effective against the variants that have emerged so far.

There’s also an outstanding question about how long immunity conferred by the vaccines will last. Current data suggests that immunity is durable for at least six months to a year, and time will tell whether it’s longer than that. In any event, many experts believe that people who’ve been vaccinated will require a booster dose at some point in the future, perhaps annually like with the flu shot, to maintain the antibodies needed to fight the coronavirus indefinitely.

For now, Doggett says that “having everyone in our immediate family vaccinated has allowed us to breathe a collective sigh of relief. As parents, the best things we can do to protect our kids are to get vaccinated ourselves, get our kids vaccinated as they become eligible and encourage everyone else to do the same.”

And Doggett encourages parents who might be hesitant “to look at the data from reliable sources and weigh the pros and cons. When you do that, it’s not a hard decision to get your kids vaccinated.”

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COVID-19 Vaccines for Children: Timing, Side Effects and More originally appeared on

Update 06/04/21: The story was previously published at an earlier date and has been updated with new information.

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