Kids vaccinated against COVID may have lower rates of asthma symptoms

Girl with asthma with mom

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COVID-19 vaccination may help protect children aged 5 and older against symptomatic asthma, according to a Nemours Children's Health–led research team.

The team calculated state-level changes in parent-reported asthma symptoms for 2020 and 2021 compared with 2018 to 2019, evaluated state-level time trends, and linked trend associations with state-level variables from the same time.

The observational study used state data on parent-reported asthma symptom rates in children from the National Survey of Children's Health 2018-2019 and 2020-2021; age-adjusted COVID-19 death rates from the US Centers for Disease Control and Prevention (CDC) from 2020 and 2021; percentage of the population aged 5 years and older who completed the COVID-19 primary vaccination series in 2020 or 2021; and indoor face-covering requirements through August 2021 from 20 states and Washington, DC.

"Social distancing measures in 2020 were associated with lower rates of emergency visits and hospitalizations for asthma among children," the researchers wrote. "Individual-level risk of COVID-19 infection was reduced with vaccination against SARS-CoV-2 for adults and children in 2020 and 2021, and several states sustained other infection prevention efforts (eg, face mask requirements) into 2021." 

The findings were published this week in JAMA Network Open.

Symptom rates waned during study

Average state-level rates of parent-reported asthma symptoms decreased from 7.77% in 2018 to 2019 to 6.93% in 2020 to 2021. The absolute average change score was −0.85 percentage points.

The average age-adjusted state COVID-19 death rate was 80.3 per 100,000 people in 2020, rising to 99.3 per 100,000 in 2021. The average state COVID-19 primary vaccination series completion rate was 72.3% through December 2021.

Anything we can do to help kids avoid flare-ups is beneficial.

Linear regression showed that, with each increase of 10 percentage points in COVID-19 vaccination coverage, the prevalence of childhood asthma symptoms fell by 0.36 percentage points. The asthma symptom rate was not tied to state COVID-19 death rates or face-covering mandates. State COVID-19 vaccination rates were inversely correlated with state COVID-19 death rates in 2021 but not 2020 and were positively correlated with face-covering requirements.

"Whether asthma is mild or severe, it affects children's quality of life," lead author Matthew Davis, MD, said in a Nemours news release. "So anything we can do to help kids avoid flare-ups is beneficial."

Inability to test differences in symptoms by vaccination status

"In this study, which is the first population-level parent-reported childhood asthma symptom prevalence and COVID-19 vaccination study we know of, we found that higher COVID-19 vaccination rates may confer protection against symptomatic asthma," the researchers wrote.

In addition to COVID-19, they said, vaccination may also protect against infection with other human coronaviruses through cross-reactive antibody responses. 

"Community-level immunity in states with higher vaccination rates may have helped reduce children's asthma risk," they wrote. "In contrast, neither concurrent exposure to high population-level burden of COVID-19–attributed disease nor sustained state-level face mask requirements were associated with concurrent trends in parent-reported symptomatic childhood asthma."

The authors cautioned that they couldn't assess differences in symptomatic asthma among vaccinated versus unvaccinated children because state data on COVID-19 vaccine uptake among children with a history of asthma were unavailable.

"Nonetheless, reduction in symptomatic asthma among children in 2020 and overall individual-level COVID-19 mortality reduction with vaccination against SARS-CoV-2 offer external support for our state-level findings," they concluded. "Moreover, the absence of association of COVID-19 vaccination (administered predominantly in 2021) with population-level COVID-19 mortality in 2020 serves as a negative control."

They added that the results should be further studied to determine whether asthma symptom rates in children could be driven down through continued efforts to improve COVID-19 vaccine coverage in this age-group.

Ongoing vaccination against COVID-19 may offer direct benefits for children with a history of asthma, but this must be confirmed with further research.

"Ongoing vaccination against COVID-19 may offer direct benefits for children with a history of asthma, but this must be confirmed with further research," coauthor Lakshmi Halasyamani, MD, of Endeavor Health in Evanston, Illinois, said in the release. "It also raises the question of whether broader population-level COVID-19 vaccination among children and adults can help protect children with asthma, too."

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