Children as Young as 6 Months Now Eligible for COVID-19 Vaccine

St. Louis Children’s Hospital physician discusses the vaccine for the youngest children

Many parents have been eagerly awaiting the opportunity to vaccinate their very young children — and, finally, that opportunity has arrived. The U.S. Centers for Disease Control and Prevention (CDC) has recommended both the three-dose Pfizer/BioNTech and two-dose Moderna COVID-19 vaccines for children as young as 6 months old.

On June 18, CDC director Rochelle Walensky, MD, approved the recommendations of the U.S. Food and Drug Administration (FDA) and the CDC’s Advisory Committee on Immunization Practices.

Parents can begin scheduling vaccinations through BJC at

Many parents still have questions, however, about the safety and effectiveness of the vaccine. Jason Newland, MD, Washington University pediatric infectious diseases specialist at St. Louis Children’s Hospital, answers some of the most frequently asked questions about children and the COVID-19 vaccine.

How do we know the COVID-19 vaccine is safe and effective for young children?

Both the Pfizer and Moderna vaccines underwent extensive randomized, controlled studies or trials. These trials included more than 4,000 children and looked at the safety and effectiveness of the vaccine. The vaccines were found to be extremely safe and very effective — even during the omicron surge — providing 95% to 100% effectiveness against suffering from a severe case of COVID-19.

We’ve been waiting for a vaccine for this age group for quite some time. Why did these trials take so much longer?

Trials follow the data, not a pre-determined timeline. We needed to make sure the vaccine was both safe and effective before approval was granted. The time that was taken was necessary to enroll these children and to follow them long enough to be confident.

What kind of dosage should we expect?

Children get a smaller dose of COVID-19 vaccine than teens and adults. Moderna uses one-fourth of the adult dose for children 6 months through 5 years in a two-dose series, given four to eight weeks apart. Pfizer uses one-tenth of its adult dose for children 6 months through 4 years in a three-dose series. The first and second doses are separated by three to eight weeks and the second and third doses are separated by at least eight weeks.

What side effects and long-term effects should we expect?

Most reported side effects are mild, temporary and like those experienced after routine vaccines. Younger children may experience fewer side effects after COVID-19 vaccination than teens or young adults. For children 4 years and older, side effects are more common after the second dose and can include:

  • Pain, swelling and redness in the arm where the shot was given

  • Fever

  • Tiredness

  • Headache

  • Chills

  • Muscle or joint pain

  • Swollen lymph nodes

For children 3 years and younger, common side effects can include:

  • Pain where the shot was given

  • Swollen lymph nodes

  • Irritability or crying

  • Sleepiness

  • Loss of appetite

Serious side effects are rare, and some children experience no side effects. Most children experience minor side effects lasting no longer than one to two days.

If my child is turning 5 soon, should I wait until then to get him vaccinated?

Get your child vaccinated now. The data continues to demonstrate that, if you are up to date on your vaccination, you are better protected against the different variants. We’ve never been able to predict when we’ll see an uptick in cases, but we know the vaccines prevent serious disease.

Who is eligible for boosters?

A booster dose is not yet authorized for children 6 months through 4 years. The CDC recommends that everyone 5 years and older get a booster dose at least five months after completing the COVID-19 vaccine primary series.

Why is it important to have my child vaccinated against COVID-19?

More than 400 children under age 4 have died from COVID-19. With the vaccine, we can now protect these younger children. While most children don’t experience serious illness from COVID-19, some children who contract it do end up in the hospital with complications, such as multisystem inflammatory syndrome (MIS-C). Also, by having your children vaccinated, you’re adding another layer of protection for your most vulnerable loved ones, such as grandparents, family members with cancer or others at high risk of serious illness.

Why have more children become sick with COVID-19 this year than last year?

First, young children were unvaccinated. Since they weren’t eligible for vaccination, they were the least protected. Second, the more recent variants, especially omicron, are more transmissible than earlier variants. And it appears that, while the young children seemed to be more protected in the early days of the pandemic, that has not been the case with these more transmissible variants.

Should I get my child vaccinated if she already had COVID? Does it matter whether she had delta, omicron or BA.2?

Children still need to be vaccinated, even if they’ve had COVID. All the data continue to show that those who’ve had infection and been vaccinated show a high level of immunity, even against other variants, and the variant she had does not matter. So, you should get your child vaccinated. If your child had COVID very recently, consult with your pediatrician on the best time to get her vaccinated.

How much protection against COVID-19 does the vaccine offer to children?

It’s likely 95% to 100% effective against serious disease.

But I thought children get very mild symptoms or no symptoms at all if they are infected with COVID-19?

There’s a misconception that children don’t get seriously ill or die from COVID-19. While most children who get COVID-19 do recover without needing hospitalization or developing complications, some do end up seriously ill and some don’t recover.

We’ve seen that one of the most serious complications of COVID-19 in children is multisystem inflammatory syndrome (MIS-C), which can affect many parts of the body, including the heart, lung, brain, kidneys, eyes and intestines.

Is the vaccine dose and schedule for children the same as for adults, 12-17, and 5-11?

The CDC website provides detailed information about the various dosing schedules for different age groups.

What’s the recommendation for spacing between the COVID-19 vaccine and the flu shot, MMR (measles, mumps, rubella) or other vaccines required for school-age children?

You can get the COVID-19 vaccine at the same time as any other vaccine. If multiple vaccines are given at a single visit, each injection will be given in a different injection site, according to recommendations by age.

Does the vaccine cause infertility or other developmental problems that parents need to worry about?

The vaccine has been studied for at least 18 months. All of the major professional obstetrics and gynecology organizations have indicated that the vaccine has not impacted fertility or the development of children born to women who received the vaccine.

Is there potential for breakthrough cases of COVID among this group?

Yes. The reality is that none of these vaccines is 100% effective against symptomatic disease, but most importantly they are 95% to 100% effective against severe disease, meaning ending up in the hospital or having serious complications such as death. So, yes, there is a chance there will be breakthrough infections — but they’ll be shorter and milder, and the vaccine will protect against complications such as long COVID and multi-system inflammatory disease.

Will my young children need to get boosted?

We’ll await the FDA and CDC input, but it’s a possibility that boosters will be recommended for this youngest population.

What is the most important thing parents should know about the COVID-19 vaccine?

It’s safe, and continues to be safe, after millions and millions and millions of doses that have been given. It’s effective — and it’s most effective against serious disease that lands children in the hospital. Finally, it will protect your loved ones from getting COVID-19, especially the most vulnerable, like grandparents and great-grandparents, family members with cancer, those who have had a transplant, and other loved ones who are at risk of serious disease. It also will give you peace of mind in situations such as travel or indoors, especially for 1-year-olds who cannot wear a mask. And you don’t have to stay home with your kids when you get exposed to the virus because they’ve been vaccinated.

Special considerations for infants

Is the vaccine safe for babies?

The Moderna and Pfizer vaccine studies have looked at babies and children 6 months and older. And the vaccines have been shown to be safe. Infants may experience a slight fever or be irritable, but they’ve done very well after vaccination.

What’s the recommendation for spacing between the COVID-19 vaccine and the flu shot, MMR (measles, mumps, rubella) or other vaccine series required or recommended for infants?

It is safe to get the COVID-19 vaccine when the infant is 6 months or older, and the vaccine does not need to be spaced out. Infants can get the COVID-19 vaccine along with any other vaccine.

If I was vaccinated before or during pregnancy, is my baby protected? And, if I’m vaccinated and breastfeeding, am I passing on any COVID-19 protection to my baby?

Pregnant women who are vaccinated pass antibodies on to their newborns at the time of birth. So, not only does vaccination in pregnant women prevent serious disease for the moms, it also provides protection for their babies. There is also data that suggests breastfeeding moms who have been vaccinated are passing that protection on to their kids, so breastfeeding can provide additional protection until the baby can be vaccinated.

Do babies even get COVID-19?

Yes. We’ve seen respiratory symptoms like those with RSV or influenza in very young children who contract COVID-19 — along with runny noses, coughs, aches, mild fevers and generally not feeling well. It most resembles influenza; however, recent data suggests that COVID is worse for kids than the flu.

What are the risks when an infant gets COVID?

Because COVID can cause a fever, very young infants — especially those younger than 2 months — are likely to end up in the hospital. So it’s important that we do everything we can to prevent them from getting COVID, such as making sure all of your loved ones are vaccinated and getting your baby vaccinated when he or she becomes of age at 6 months.

Can a newborn, we’re talking 5 weeks old, receive the vaccine? If not, are they protected at all?

The best way to protect newborns, especially during the first five months of life, is for the baby’s mother and other family members to be vaccinated. Pregnant women who are vaccinated pass antibodies on to their newborns, as do breastfeeding mothers who are vaccinated.

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