COVID-19 Vaccines Safe and Effective in Children Aged 5-11 Years, According to New Research

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COVID-19 vaccination was associated with lower risks of SARS-CoV-2 infection, COVID-19-related illnesses, and hospitalizations due to COVID-19-related illnesses in children aged 5 to 11 years, according to a recent systematic review and meta-analysis.

The findings, published in JAMA Pediatrics, also show that COVID-19 vaccination was associated with a higher risk of any adverse events (AEs) compared with placebo, although most AEs resolved within several days.

“Our findings can help inform physicians and other clinicians, parents, and policy makers about the effectiveness and safety of COVID-19 vaccination for children aged 5 to 11 years,” wrote first author Atsuyuki Watanabe, MD, and colleagues.

COVID-19 mRNA vaccines have been available for adolescents and children since 2021, however, “the benefit of mRNA vaccines in children aged 5 to 11 years is not firmly established,” wrote researchers.

To evaluate the efficacy and safety of mRNA COVID-19 vaccines in this population, investigators searched PubMed and Embase databases for randomized clinical trials (RCTs) and observational studies that compared vaccinated and unvaccinated children and reported efficacy and safety outcomes.

The primary outcome was SARS-CoV-2 infections with or without symptoms, and the secondary outcomes included symptomatic SARS-CoV-2 infections, hospitalizations, and multisystem inflammatory syndrome in children (MIS-C). Also, the incidences of each AE following vaccination were evaluated.

Overall, 2 RCTs and 15 observational studies involving 10 935 541 vaccinated children (mean age range, 8.0-9.5 years) and 2 635 251 unvaccinated children (mean age range, 7.0-9.5 years) were included in the analysis.

Findings

According to the study results, 2-dose mRNA COVID-19 vaccination compared with no vaccination was associated with lower risks of SARS-CoV-2 infections with or without symptoms (odds ratio [OR] 0.47, 95% CI 0.35-0.64), symptomatic SARS-CoV-2 infections (OR 0.53 95% CI 0.41-0.70), hospitalizations (OR 0.32, 95% CI 0.15-0.68), and MIS-C (OR 0.05, 95% CI 0.02-0.10).

“Our finding that mRNA vaccination in children aged 5 to 11 years was not only associated with lower risks of acute infection but also associated with lower risks of hospitalization and MIS-C was important since it will aid in addressing the misunderstandings that vaccination does not benefit children,” wrote the research team.

Vaccination, compared with placebo, was significantly associated with a higher risk of any AE (OR, 1.92; 95% CI, 1.26-2.91), but vaccination was not statistically significant for AEs that prevented normal daily activities (OR 1.86, 95% CI 1.26-2.91).

Findings from 7 studies that assessed AEs among vaccinated children showed most vaccinated children experienced at least 1 local AE after the first dose (86.3%; 95% CI, 74.1%-93.3%) and second dose (86.3%; 95% CI 73.8-93.4). Following the second injection, the incidence of AEs that prevented normal daily activities was 8.8% (95% CI, 5.4%-14.2%) and that of myocarditis was estimated to be 1.8 per million (95% CI, .000%-.001%).

Most of the AEs lasted only 1 to 2 days, except for local pain and redness, which lasted for 3 days or more, according to investigators.

There were some limitations to the current study. While Watanabe and colleagues planned to evaluate all mRNA COVID-19 vaccines, most of the included studies only evaluated the effects of BNT162b2 by Pfizer-BioNTech, making the external validity of the findings unclear.

The detailed history and patient characteristics of serious AEs following vaccination were unavailable, which warrants future studies focusing on the risk factors and prognoses of serious AEs among children. The study only assessed vaccine effectiveness for acute infection, therefore vaccine efficacy against post COVID conditions and long-term safety is still unknown.

Lastly, just 1 study in the analysis investigated a third vaccine dose. “Since booster doses are expected to provide additional protection against infection and severe progression, further investigations on additional doses and omicron-bivalent vaccines are awaited,” wrote Watanabe et al.

Reference: Watanabe A, Kani R, Iwagami M, et al. Assessment of efficacy and safety of mRNA COVID-19 vaccines in children aged 5 to 11 years: A systematic review and meta-analysis. JAMA Pediatr. Published online January 23, 2023. doi:10.1001/jamapediatrics.2022.6243.