CDC approves coronavirus vaccine for kids 6 months to 5 years

Children as young as 6 months can now receive the Pfizer BioNTech and Moderna mRNA vaccines.

- By Elizabeth Valente

The mRNA vaccines by Pfizer BioNTech and Moderna have been approved by the Centers for Disease Control for children as young as 6 months.

On June 18, 2022, the Centers for Disease Control and Prevention 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-19 cases rising, many parents are eager to vaccinate their youngest kids. Grace Lee, 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 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 and may prevent long COVID, which can be 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 in young children. 

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

If your child receives the Pfizer vaccine, it is a three-dose vaccine series: the second three to eight weeks after the first dose, and the third dose more than eight weeks after the second.

For the Moderna vaccine, it is a two-dose vaccine series: the second four to eight weeks after the first. 

Children who are moderately or severely immunocompromised may need additional doses, as with immunocompromised 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.

Grace Lee

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 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 — it varies by the individual. The primary vaccine series offers additional and reliable protection against severe illness and death.

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 COVID-19 infection, but waiting until all symptoms have resolved is best.

In addition, people who had a recent 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 their 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 to 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 maskdoing proper handwashing and following other steps to keep people with a high risk of infection safe.

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 to 23 months may be fussy or 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.

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 because 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.

About Stanford Medicine

Stanford Medicine is an integrated academic health system comprising the Stanford School of Medicine and adult and pediatric health care delivery systems. Together, they harness the full potential of biomedicine through collaborative research, education and clinical care for patients. For more information, please visit

2023 ISSUE 3

Exploring ways AI is applied to health care