Dec. 31, 2021 -- The CDC released two studies on Thursday that showed vaccine safety for ages 5-11 and emphasized the importance of vaccinating children against the coronavirus to prevent serious illness and hospitalization.

In one study, researchers found that serious problems were rare among children who had received the Pfizer vaccine.

In another study, researchers looked at hundreds of pediatric hospitalizations from the summer and found that nearly all of children who developed severe COVID-19 weren’t fully vaccinated.

“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,” the authors of the second study wrote.

Nearly 9 million doses of the Pfizer vaccine have been given to ages 5-11 in the U.S. so far, according to The New York Times. By mid-December, or about six weeks after the age group became eligible for vaccination in October, the CDC said it had received very few reports of serious problems.

CDC researchers evaluated reports received from doctors and the public, including survey responses from parents and guardians of about 43,000 children between ages 5-11. Many children reported non-serious events such as pain at the injection site, fatigue, or a headache, especially after the second dose.

Among more than 4,100 adverse event reports received in November and December, 100 were for serious events, with the most common being fever or vomiting.

The CDC had received 11 verified reports of myocarditis, or inflammation of the heart muscle, which has been noted as a rare side effect of the vaccine among boys and men between ages 12-29. Among those, seven children had already recovered and four were still recovering at the time of the report.

The CDC received reports of two deaths — girls who were ages 5 and 6 — who had chronic medical conditions and were in “fragile health” before their shots. The agency said that no data suggested a “causal association between death and vaccination.”

The CDC also received some reports that children between ages 5-11 received the larger vaccine dose meant for older children and adults. Most reports said that the children didn’t experience any problems after an incorrect dose.

In a separate study about pediatric hospitalizations, CDC researchers looked at more than 700 children under age 18 who were hospitalized for COVID-19 in July and August at six children’s hospitals in Arkansas, Florida, Illinois, Louisiana, Texas, and Washington, D.C.

Researchers found that only one of the 272 vaccine-eligible patients between ages 12-17 had been fully vaccinated, and 12 were partially vaccinated.

In addition, 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.

Overall, about 30% of the children had to be treated in intensive care units, and 15% needed invasive medical ventilation, CDC researchers found. Nearly 3% had multisystem inflammatory syndrome in children, or MIS-C, which is a rare but serious inflammatory condition associated with COVID-19.

Among all the children hospitalized with COVID-19, about 1.5% died.

“Few vaccine-eligible patients hospitalized for COVID-19 were vaccinated, highlighting the importance of vaccination for those aged ≥5 years and other prevention strategies to protect children and adolescents from COVID-19, particularly those with underlying medical conditions,” study authors wrote.

Show Sources

CDC: “COVID-19 Vaccine Safety in Children Aged 5-11 Years – United States, November 3-December 19, 2021.” “Characteristics and Clinical Outcomes of Children and Adolescents Aged <18 Years Hospitalized with COVID-19 – Six Hospitals, United States, July-August 2021.”

The New York Times: “Covid vaccines rarely lead to problems in younger children, according to two CDC reports.”

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