No Concerning Side Effects Found in Young Children Who Received the COVID-19 Vaccine

No serious side effects were found in children aged 5 years or younger who were given mRNA COVID-19 vaccines, according to a recent study published in Pediatrics.

Researchers of the study examined the patient records of approximately 550,000 children under 5 from June 2022 to March 2023 for both the Pfizer-BioNTech and Moderna vaccines. Information regarding COVID-19 vaccine safety is limited among children in that age group.

Patient records were collected from the Vaccine Safety Datalink, which consists of data provided by 8 health systems: 5 Kaiser Permanente regions, Marshfield Clinic in Wisconsin, HealthPartners in Minneapolis, and Denver Health in Colorado.

Weekly surveillance monitoring, also known as rapid cycle analysis (RCA), of more than 245,000 COVID-19 mRNA vaccine doses did not detect a safety signal for any outcome in the 21 days after vaccination.

Within the study’s timeframe, 135,005 doses of the Pfizer vaccine were given to children aged 6 months to 4-years-old. Children 6 months to 5-years-old were given 112,006 doses of the Moderna vaccine.

Researchers also examined patient records for 23 serious and potential side effects, including blood clots, seizures, stroke, and brain inflammation. No safety concern for any of the serious side effects were found. In particular, the study found no concern for seizures after vaccination, something occasionally seen following other routine childhood immunizations in children under 2 years old.

It’s important to note no cases of myocarditis or pericarditis occurred after vaccination, as well.

Myocarditis has emerged as a rare side effect of COVID-19 vaccination, mostly among teenage or young adult men.

Some mild side effects of sore arms and brief fevers after immunization, however, have been previously reported by the CDC.

Nicola Klein, MD, Ph.D., director of the Kaiser Permanente Vaccine Study Center and research scientist with the Division of Research, claimed in a release by Kaiser that parents can be assured the analysis found no serious side effects from the mRNA vaccines.

"Parents can protect their young children from COVID-19 in the same way they vaccinate their children to protect from other serious childhood diseases," Klein said.

"Vaccinating children against COVID-19 benefits them by reducing the burden of illness, avoiding spreading the virus to family and others, and mitigating the small but real risk of serious illness."