Children and adolescents with poorly controlled asthma were three to six times more likely to be hospitalized with COVID-19 infections, based on data from a national study of more than 750,000 children in Scotland.
Although the majority of COVID-19 cases in children have been mild, some children require hospitalization, wrote Ting Shi, PhD, of the University of Edinburgh (Scotland) and colleagues.
Vaccination policies to potentially reduce infection and hospitalization of children remain inconsistent, the researchers said. Identifying which school-age children would derive the greatest benefit from vaccination “could help to reduce the risk of infection and consequently the need for children to have time off school; and might also reduce the risk of spread of SARS-CoV-2 within schools and households,” but the potential benefits of vaccination for children with asthma in particular have not been well studied, they wrote.
The United Kingdom’s Joint Commission on Vaccination and Immunisation commissioned research on the rates of hospitalization among children with poorly controlled asthma. In a national incidence cohort study published in The Lancet Respiratory Medicine, the researchers reviewed data from all children aged 5-17 years in Scotland who were enrolled in the linked dataset of Early Pandemic Evaluation and Enhanced Surveillance of COVID-19 (EAVE II). The total number of children in the dataset was 752,867, and 63,463 (8.4%) of these had diagnosed asthma. Among the children with asthma, 4,339 (6.8%) had confirmed COVID-19 infections between March 1, 2020, and July 27, 2021. A total of 67 infected children were hospitalized. Of the 689,404 children without asthma, 40,231 (5.8%) had confirmed COVID-19 infections, and 382 (0.9%) of these children were hospitalized.
Overall, hospital admission rates for COVID-19 were significantly higher among children with asthma, compared to those without asthma (adjusted hazard ratio, 1.49), and the rates increased among children with poorly controlled asthma.
The researchers used previous hospital admission for asthma as a measure of uncontrolled asthma, and found that hospitalization was at least six times as likely for children with poorly controlled asthma, compared with those with no asthma (aHR, 6.40), although children with well-controlled asthma also had an increased risk of hospitalization, compared with those with no asthma (aHR, 1.36).
When the researchers used oral corticosteroid prescriptions as an indicator of uncontrolled asthma, the adjusted hazard ratios were 3.38, 3.53, 1.52, and 1.34 for children with prescribed corticosteroid courses of three or more, two, one, and none, respectively, compared with children with no asthma.
These hazard ratios remained significant after controlling for factors including age, sex, socioeconomic status, comorbidity, and previous hospital admission, the researchers wrote.
In an age-based analysis, results were similar for children aged 12-17 years, but in children aged 5-11 years, the hospitalization risk decreased for those with one course of corticosteroids and reached the highest rate for those with three or more courses, rather than two courses.
The study findings were limited by several factors including the relatively small numbers of COVID-19 hospitalizations, ICU admissions, and deaths in children with asthma, the researchers noted. Other limitations include potential changes in asthma control over the study period, and lack of data on certain confounders such as tobacco use, unsuitable housing, and ethnicity, they noted. However, the results were strengthened by the use of a large, national dataset, and access to electronic health records, they said.
The findings reflect data from previous studies suggesting increased risk of hospitalization for patients with respiratory illness who develop COVID-19 infections, the researchers wrote.
The results emphasize the importance of good asthma control to protect children from severe COVID-19, and careful monitoring of children with poorly controlled asthma who do become infected, they added.
“The findings from this linkage of multiple data sources have helped inform the prioritisation of school-aged children with poorly controlled asthma for vaccines,” they concluded.