Child getting Vaccine

Updated June 14, 2021

On May 10, 2021, the Food and Drug Administration (FDA) granted emergency use authorization (EUA) to a COVID-19 vaccine developed by Pfizer-BioNTech for children ages 12 to 15.

It marked the first time the FDA authorized a COVID-19 vaccine for children younger than age 16. Previously, the Pfizer vaccine was available only for people age 16 and older. Vaccines developed by Moderna and Johnson & Johnson/Janssen are available only for adults age 18 and older.

Before the FDA authorized the Pfizer vaccine for children ages 12 to 15, it had to meet standards for safety and effectiveness. According to reported data, the vaccine is safe and effective for children ages 12 to 15.

Here’s what you need to know about the vaccine’s safety for children.

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Were the COVID-19 Vaccines Tested in Children?

Before receiving EUA, the Pfizer vaccine went through months of clinical trials in children ages 12 to 15. The trials measured the safety and effectiveness of the vaccine in more than 2,000 adolescents. Half received the vaccine and half received a placebo.

The authorization process worked the same way as it did for adults. For a vaccine to receive EUA, data must show that the vaccine’s benefits outweigh the risks.

Data from the clinical trials showed the Pfizer vaccine was safe for use in children ages 12 to 15, according to the FDA. It also showed the vaccine was 100% effective in preventing COVID-19.

“All of the evidence so far says that the vaccine is extremely safe in kids,” says John Williams, MD, chief, Pediatric Infectious Diseases, UPMC Children’s Hospital of Pittsburgh. “The vaccine has been given to over 100 million adults with essentially no serious side effects. There’s no reason to think that younger children will be any different.”

COVID-19 Vaccine Side Effects in Children

Teens and pre-teens who received the Pfizer vaccine reported common side effects. These side effects are generally minor and typically subside within 1 to 3 days after receiving the vaccine. The side effects are a result of the immune system’s response to the vaccine.

According to the FDA, the most commonly reported side effects in children ages 12 to15 included:

  • Pain at the injection
  • Fatigue
  • Headache
  • Fever/chills
  • Muscle/joint pain

These side effects are consistent with side effects reported in people age 16 and older.

With the exception of injection site pain, these side effects were more commonly reported after the second dose. Side effects are possible after both doses, and it’s also possible to experience no side effects.

The Centers for Disease Control and Prevention (CDC) is monitoring reports of the heart conditions myocarditis and pericarditis in people who received the Moderna and Pfizer vaccines, especially adolescents and young adults.

According to the CDC, the reported cases were rare and happened mostly in male adolescents and young adults 16 and older. Symptoms usually presented within days of vaccination, and patients typically responded well to rest and medications.

The CDC continues to recommend vaccination for Americans 12 and older.

Is the COVID-19 Vaccine Effective in Children?

According to the FDA, clinical trials of the Pfizer vaccine in children ages 12 to 15 showed it was 100% effective in preventing COVID-19.

While more data is needed to evaluate the vaccine’s effectiveness in preventing the spread of the virus from person to person, to date studies of vaccinated adults show that vaccinated people rarely transmit SARS-CoV-2 to others. It is not clear at this time how long the vaccine provides protection.

Why Do Kids Need the COVID-19 Vaccine?

Although fewer children than adults have gotten COVID-19, it is possible for children to become infected.

Between March 1 and April 30, 2021, the Centers for Disease Control and Prevention (CDC) reported about 1.5 million cases of COVID-19 in children ages 11 to 17 in the United States, according to the FDA.

“It’s terrific news, as a parent and pediatrician, that our kids can be vaccinated,” Dr. Williams says. “Although severe COVID-19 is rare in young kids, it does happen, and the vaccine will protect them. Young people can also spread COVID-19 to vulnerable family members, and we know that the vaccine is extremely effective at preventing this.”

Most children experience mild illness from COVID-19 or are asymptomatic. But severe illness, hospitalization, and death are possible. Dr. Williams says more than 15,000 children have been hospitalized from COVID-19 in the past year. More than 300 children have died. Those numbers are greater than the number of hospitalizations and deaths from seasonal flu.

Some children who have had COVID-19 have developed a condition known as Multisystem Inflammatory Syndrome in Children (MIS-C). MIS-C is a rare but serious condition that can affect different body parts and cause serious symptoms.

Other children who have had COVID-19 have experienced long-term symptoms.

“While most children who are infected with SARS-CoV-2 have mild disease, some kids have severe disease such as MIS-C, long-term symptoms consistent with long COVID, or require monitoring by a cardiologist for effects on the heart prior to returning to sports,” says Megan Freeman, MD, PhD, fellow, Pediatric Infectious Diseases, UPMC Children’s Hospital of Pittsburgh. “Vaccination can help protect the individual and the community as well.”

For more information about the COVID-19 vaccine, visit For information on how to schedule a vaccine for your child at UPMC, visit


Food and Drug Administration, Coronavirus (COVID-19) Update: FDA Authorizes Pfizer-BioNTech COVID-19 Vaccine for Emergency Use in Adolescents in Another Important Action in Fight Against Pandemic. Link

About UPMC

Headquartered in Pittsburgh, UPMC is a world-renowned health care provider and insurer. We operate 40 hospitals and 700 doctors’ offices and outpatient centers, with locations in central and western Pennsylvania, Maryland, New York, and internationally. We employ 4,900 physicians, and we are leaders in clinical care, groundbreaking research, and treatment breakthroughs. U.S. News & World Report consistently ranks UPMC Presbyterian Shadyside as one of the nation’s best hospitals in many specialties and ranks UPMC Children’s Hospital of Pittsburgh on its Honor Roll of America’s Best Children’s Hospitals.