mRNA Vaccine Associated With Lower Risk of Symptomatic COVID-19 in Children

Two doses of the COVID-19 messenger RNA (mRNA) vaccine is associated with a lower risk of SARS-CoV-2 infection in children aged 5 to 11 years compared to not being vaccinated, according to new data published in JAMA Network Open. Although the vaccine can prevent severe COVID-19-related illnesses and hospitalizations, it is associated with low-grade adverse events (AEs).

“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 multisystem inflammatory syndrome in children (MIS-C) was important since it will aid in addressing the misunderstandings that vaccination does not benefit children,” the study authors wrote in the article.

The primary outcome of the study was a symptomatic or asymptomatic response to COVID-19 infection. Secondary outcomes were infections, hospitalizations, and MIS-C, along with vaccine AEs.

mRNA vaccines have already been found to be safe and effective against SARS-CoV-2 infection, which has led to serious illness and the death in more than 6.5 million people around the world. The vaccine can prevent serious progression and post-COVID-19 conditions in adults, and mounting evidence supports its efficacy for adolescents and children, according to the study investigators.

Randomized clinical trials (RCTs) show the mRNA vaccine is 85% to 95% effective at preventing symptomatic infection in adolescents and children. Although the risk of serious conditions such as myocarditis and MIS-C are incredibly low, many parents remain wary about the vaccine’s safety.

Researchers performed a systematic review and meta- analysis of 17 studies, looking at 10,935,541 vaccinated children and 2,635,251 unvaccinated children aged 5 to 11 years. They examined the vaccine’s safety and efficacy for preventing acute infection and related hospitalizations.

The data show that a 2-dose mRNA vaccination decreased the risk of symptomatic infection, hospitalization, and MIS-C. Both vaccine doses caused at least 1 local AE in 86.3% of patients, but a small 0.001% experienced severe conditions, such as myocarditis. The vaccine was also found to be more effective against the Delta subvariant compared to Omicron, although it is associated with fewer symptoms for both compared to being unvaccinated.

The study includes limitations, with the primary limitation being the team did not evaluate all eligible mRNA vaccines. Additionally, the investigators used a 1-group meta-analysis design to estimate AEs, the study may include reporting bias, and there were no studies on post-COVID-19 conditions or long-term safety.

A separate survey found that 25% to 46% of US adults are hesitant about vaccinating their children. At least 80% of respondents reported feeling worried about severe AEs, but one of the primary causes for vaccine hesitancy is misunderstanding the vaccine’s efficacy, according to those researchers. At least 26% did not think the vaccine would offer their children protection.

“Our findings can help address the hesitancy related to mRNA COVID-19 vaccines [and] 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,” the study authors wrote in the article.

Reference

Watanabe, Atsuyuki, Kani, Ryoma, Iwagami, Masao, et al. Assessment of Efficacy and Safety of mRNA COVID-19 Vaccines in Children Aged 5 to 11 Years. JAMA Pediatr. Published online January 23, 2023. doi:10.1001/jamapediatrics.2022.6243