Large study shows safety of COVID mRNA vaccines in young children

boy getting vaccinated

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Messenger RNA vaccines for COVID-19 pose little risk to young children, with no myocarditis (inflammation of heart muscle) or pericarditis (inflammation around the heart) observed in vaccine recipients age 0 to 4. The reassuring findings were published today in Pediatrics.

The safety data were collected via the Vaccine Safety Datalink (VSD), a collaboration with the Centers for Disease Control and Prevention that collects patient information from eight major health systems in the United States, including five Kaiser Permanente regions in Colorado, California, and Washington, as well as the Marshfield Clinic in Wisconsin, HealthPartners in Minneapolis, and Denver Health in Colorado.

Parents can be assured that this large study found no serious side effects from the mRNA vaccines.

The study included 135,005 doses of the Pfizer COVID-19 vaccine given to children age 6 months to 4 years and 112,006 doses of the Moderna COVID-19 vaccine given to children age 6 months to 5 years between June 2022 to March 2023.

23 serious outcomes considered

Medical records were searched for 23 serious potential vaccine side effects, including blood clots, seizures, stroke, the aforementioned myocarditis, and brain inflammation, in days 1 to 21 postvaccination.

Rate ratios (RRs) were not elevated for any prespecified outcomes following any dose of Pfizer-BioNTech and Moderna vaccine, and none of the outcomes met the signaling threshold, the authors wrote.

One case each of hemorrhagic stroke and pulmonary embolism were identified after vaccination, but later ruled to be unrelated to vaccination, as the patients had congenital abnormalities.

In addition, "One case of multisystem inflammatory syndrome in children (MIS-C) was identified postvaccination, but chart review found the child developed COVID-19 infection after vaccination and before MIS-C diagnosis," the authors wrote.

Data offer reassurance to parents

The data provide 9 months worth of reassurance to parents, the authors said. However, they caution the vaccine uptake in the studied age group was low, with only 24.7% of the eligible VSD population having received at least 1 vaccine dose during the study period.

"Parents can be assured that this large study found no serious side effects from the mRNA vaccines," said senior author Nicola Klein, MD, PhD, director of the Kaiser Permanente Vaccine Study Center in a press release.

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

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