CDC Approves COVID-19 Vaccines for Kids Under 5 Years of Age—What Parents Should Know

Nearly 20 million children in the U.S. under 5 years are newly eligible to receive the COVID-19 vaccine.

On June 18, 2022, the Centers for Disease Control and Prevention (CDC) approved COVID-19 vaccination for young children who are at least 6 months old. This means roughly 20 million children in the United States under 5 years are newly eligible for vaccination. With COVID cases rising, many parents are eager to vaccinate their youngest kids. Grace Lee, MD, associate chief medical officer for practice innovation and a pediatric infectious diseases physician, answers frequently asked questions about vaccines for young children.

Why should my baby or young child receive the COVID-19 vaccine?

Since the beginning of the COVID-19 pandemic, there have been over 2 million cases, 20,000 hospitalizations, and 200 deaths due to COVID-19 in children under 5 years of age. The CDC recommends a COVID-19 vaccine for children ages 6 months and older. Stanford Medicine Children’s Health encourages all families to have eligible children vaccinated with the COVID-19 vaccine.

Scientific evidence has shown that the children who received COVID-19 vaccines during testing developed high levels of virus-fighting antibodies expected to protect them against coronavirus. Vaccines continue to be effective at preventing severe illness and hospitalization, including in children with and without any underlying medical conditions.

COVID-19 vaccines can also prevent multisystem inflammatory syndrome in children (MIS-C) and may potentially prevent post-acute sequelae of COVID-19 (PASC)—i.e., long COVID—which can be very debilitating for young children. Vaccines can protect children, which in turn can reduce the risk of transmission to others.

What makes this vaccine different from the others administered to kids 5 years and older?

The only COVID-19 vaccine presently available for children older than 5 years in the U.S. is the Pfizer BioNTech mRNA vaccine. For children under 5, we now have two vaccines available. The three-dose Pfizer COVID-19 vaccine can be given to children 6 months to 4 years of age at a 3 microgram dosage. The two-dose Moderna COVID-19 vaccine is recommended for children ages 6 months to 5 years at a dose of 25 micrograms. These doses were carefully selected to ensure the vaccine was well tolerated for young children.

How many doses of vaccine are needed, and on what schedule?

If your child receives the Pfizer vaccine, it is a 3-dose vaccine series: Dose 1, then 3-8 weeks later Dose 2, then >8 weeks later Dose 3.

For the Moderna vaccine, it is a 2-dose vaccine series: Dose 1, then 4-8 weeks later Dose 2.

Children who are moderately or severely immunocompromised may need additional doses, similar to teens and adults.

How long does it take for the shots to take full effect?

A child can be considered fully immunized two weeks after the third dose of the Pfizer mRNA vaccine or two weeks after the second dose of the Moderna vaccine. Children who are moderately or severely immunocompromised are considered fully vaccinated two weeks after the final dose in the primary series.

What side effects can parents expect from the vaccines?

The most common side effects parents can expect for their child are a sore arm, headache, fever, and fatigue. Children 6–23 months may be fussy or more sleepy. Symptoms usually occur one to two days after vaccination and are mostly mild and resolve after a few days. Parents should contact their primary care provider if they have any specific concerns about side effects from a shot.

The most common side effects parents can expect for their child are a sore arm, headache, fever, and fatigue

My child is immunocompromised. Can they get the vaccine?

Yes, children who are immunocompromised should receive vaccines to reduce the risk of severe COVID-19 illness or death. Additional doses are given to children who are moderately or severely immunocompromised, since their immune response to vaccines may not be as strong as in healthy people. Please ask your doctor about when to receive COVID-19 vaccines.

Where should young children be vaccinated?

Going to your child’s primary care provider is recommended for this age group. We encourage you to use all available local and state resources to get the COVID-19 vaccine at a place and time that is convenient for your family. You can also review Stanford Medicine Children’s Health resources to help find a vaccination site for your child.

For children who have already gotten COVID-19, is it still worth their getting the vaccine, even if they were already exposed to the most recent variant?

Yes, it is still worthwhile for these children to be vaccinated. While there is protection from natural immunity, it is hard to tell just how durable and protective it is, over time—it varies by the individual. The primary vaccine series offers additional and reliable protection against severe illness and/or death.

Vaccines continue to be effective at preventing severe illness and hospitalization, including children without any underlying medical conditions.

How long after my child’s COVID-19 infection should I wait before getting them vaccinated?

The situation may vary depending on a child’s medical history and the severity of the COIVD-19 infection, but waiting until all symptoms have resolved is best.

In addition, people who recently had SARS-CoV-2 infection may consider delaying a primary series dose or their first or second COVID-19 vaccine booster dose by three months from symptom onset or positive test (if infection was asymptomatic). Studies have shown that increased time between infection and vaccination may result in an improved immune response to vaccination. Check with your child’s pediatrician for more information.

What can parents do to reduce their child’s risk of getting COVID-19?

About 59% of 12- to 17-year-olds and around 29% of children ages 5–11 are fully vaccinated, according to CDC data. A child is considered up-to-date if they have received all recommended doses for their age. I encourage everyone to keep doing their part to protect themselves and others by wearing a face mask, doing proper handwashing, and following other steps to keep people with a high risk of infection safe.

Grace Lee, MD, pediatric infectious diseases physician, answers frequently asked questions about vaccines for young children.