On 30 December 2021, the Centers for Disease Protection and Control (CDC) released two studies on COVID-19 vaccine safety for 5-11-year-olds that showed that there were few serious safety issues and showed that the vaccines prevented serious illness and hospitalization.
These two studies provide strong evidence for COVID-19 vaccine safety and effectiveness for children and should provide confidence for parents to make sure their children get the vaccine.
This post will examine these peer-reviewed articles and pull out the key data for the reader.

COVID-19 vaccine safety study
In the first study, CDC researchers found that serious adverse events were extremely rare among children who had received the Pfizer vaccine. According to the New York Times, nearly nine million doses of the Pfizer vaccine have been given to children, ages 5-11, in the US. By 19 December 2021, the last date on which data was accumulated for the study, the CDC found very reports of serious adverse events.
The CDC evaluated VAERS reports received from physicians and others for 4249 children between the ages of 5 and 11. Of those, 4,149 (97.6%) VAERS reports were for nonserious events reports including pain at the injection site, fatigue, or headache, especially after the second dose.
Of the adverse events reported to VAERS, 100 (about .001% of all children vaccinated) were for serious events with the most common being fever and vomiting. The CDC stated that “VAERS reports are classified as serious if any of the following are reported: hospitalization, prolongation of hospitalization, life-threatening illness, permanent disability, congenital anomaly or birth defect, or death.”
However, the CDC also received 11 verified reports of myocarditis, an inflammation of the heart muscle usually caused by infection. Among those individuals, seven had recovered and four were still recovering at the date of the report.
The CDC also received reports of two deaths, girls aged 5 and 6. However, they both had chronic medical conditions and were in “fragile health” before receiving the COVID-19 vaccines. The CDC found no data that indicated a “causal association between death and vaccination.”
The CDC also examined data from v-safe, which enrolled 42,504 children aged 5-11 years who received the Pfizer COVID-19 vaccine. This includes 29,899 who received the second dose.
About 1% of parents reported seeking medical care for their children in the week after vaccination. Of those, 14 (0.02%) of the children reported receiving care at a hospital. The CDC didn’t have any further information for nine of the children, but two were admitted for appendicitis, one for vomiting and dehydration, one for a respiratory infection, and one for retropharyngeal cellulitis.
Serious adverse events after the vaccine were extremely rare in these two different analyses. Moreover, most of those probably were not related to the COVID-19 vaccines, which should reassure parents of the safety of these vaccines.

Second CDC study
In the second study, CDC researchers examined 915 pediatric hospitalizations in six hospitals during July-August, 2021. They found that nearly all of the children who developed severe COVID-19 were not fully vaccinated.
- Only 0.4% of vaccine-eligible adolescents hospitalized for COVID-19 were fully vaccinated.
- Hospitalization rates have been shown to be 10 times higher among unvaccinated adolescents compared with fully vaccinated adolescents.
- About two-thirds of the hospitalized children between ages 12-17 had an underlying condition, with obesity being the most common.
- About one-third of children under age 5 had more than one viral infection.
The researchers concluded:
…this study demonstrates that unvaccinated children hospitalized for COVID-19 could experience severe disease and reinforces the importance of vaccination of all eligible children to provide individual protection and to protect those who are not yet eligible to be vaccinated.
Summary
These two studies confirm COVID-19 vaccine safety and effectiveness for children, who are an important next step in the battle to end this pandemic.
Citations
- Hause AM, Baggs J, Marquez P, Myers TR, Gee J, Su JR, Zhang B, Thompson D, Shimabukuro TT, Shay DK. COVID-19 Vaccine Safety in Children Aged 5-11 Years – United States, November 3-December 19, 2021. MMWR Morb Mortal Wkly Rep. 2021 Dec 31;70(5152):1755-1760. doi: 10.15585/mmwr.mm705152a1. PMID: 34968370.
- Wanga V, Gerdes ME, Shi DS, Choudhary R, Dulski TM, Hsu S, Idubor OI, Webber BJ, Wendel AM, Agathis NT, Anderson K, Boyles T, Chiu SK, Click ES, Da Silva J, Dupont H, Evans M, Gold JAW, Haston J, Logan P, Maloney SA, Martinez M, Natarajan P; BMBS1, Spicer KB, Swancutt M, Stevens VA, Brown J, Chandra G, Light M, Barr FE, Snowden J, Kociolek LK, McHugh M, Wessel D, Simpson JN, Gorman KC, Breslin KA, DeBiasi RL, Thompson A, Kline MW, Bloom JA, Singh IR, Dowlin M, Wietecha M, Schweitzer B, Morris SB, Koumans EH, Ko JY, Kimball AA, Siegel DA. Characteristics and Clinical Outcomes of Children and Adolescents Aged <18 Years Hospitalized with COVID-19 – Six Hospitals, United States, July-August 2021. MMWR Morb Mortal Wkly Rep. 2021 Dec 31;70(5152):1766-1772. doi: 10.15585/mmwr.mm705152a3. PMID: 34968374.