The current UK recommendation on COVID-19 vaccination for children aged 12-17 years should be expanded to include children in the five to 17 years age bracket who have been hospitalised with asthma or have been prescribed two or more courses of oral steroids for asthma within the past two years, according to the findings of a Scottish study published in The Lancet Respiratory Medicine.
The study, which was urgently requested by the Joint Commission on Vaccination and Immunisation (JCVI), analysed data from more than 750,000 school-aged children in Scotland who were included in the Early Pandemic Evaluation and Enhanced Surveillance of COVID-19 (EAVE II) dataset to identify which children with asthma are at increased risk of serious COVID-19 outcomes, and should be prioritised for vaccination.
Between March 1, 2020, and July 27, 2021, 752,867 children were included in the EAVE II dataset, 63,463 (8.4%) of whom had clinician-diagnosed and recorded asthma. Of these, 4,339 (6.8%) had RT-PCR confirmed SARS-CoV-2 infection.
In those with confirmed infection, 67 (1.5%) were admitted to hospital with COVID-19. Among the 689,404 children without asthma, 40,231 (5.8%) had confirmed SARS-CoV-2 infections, of whom 382 (0.9%) were admitted to hospital with COVID-19.
The rate of COVID-19 hospital admission was higher in children with poorly controlled asthma – defined as previous asthma hospital admission and at least two previous prescriptions for oral corticosteroids within two years of the study start date - than in those with well controlled asthma or without asthma.
When using previous hospital admission as the marker of uncontrolled asthma, the risk of COVID-19 hospitalisation was increased more than six-fold (adjusted HR 6.40; 95% CI 3.27-12.53) for those with poorly controlled asthma and by more than 30 per cent (adjusted HR 1.36; 95% CI 1.02-1.80) for those with well controlled asthma, compared with those with no asthma.
When using oral corticosteroid prescriptions as the marker of uncontrolled asthma, the adjusted HR for COVID-19-related hospital admission was 3.38 (95% CI 1.84-6.21) for those who had received at least three courses of corticosteroids in the previous two years, and 3.53 (95% CI 1.87-6.67) for those who had been prescribed two courses, compared with those with no asthma. Children who had received one course of corticosteroids had an adjusted HR of 1.52 (95% CI 0.90-2.57) and those with asthma who had not been prescribed a course of oral corticosteroids had an adjusted HR of 1.34 (95% CI 0.98-1.82), compared with children with no asthma.
The findings of the analysis – the first of its kind – suggest that school-aged children with asthma and a recent hospital admission or at least two courses of oral corticosteroids are at markedly increased risk of COVID-19 hospital admission, although it must be noted that the overall risk of admission was low, with one in 380 children with poorly controlled asthma being admitted.
Presenting the results, the authors recommend that children aged five to 17 years, with poorly controlled asthma, should be prioritised for vaccinations. It is estimated that this would translate to approximately 109,448 children across the UK.
Commenting on the research, lead author, Professor Aziz Sheikh from the University of Edinburgh, explained that “understanding which children with asthma are at increased risk of serious COVID-19 outcomes is critical to ongoing policy deliberations on vaccine prioritisation.
“The key takeaway from this study is that keeping children’s asthma under control is critical as this greatly reduces the risk of COVID-19 hospitalisation. Vaccinating those with poorly controlled asthma offers an additional important layer of protection from serious COVID-19 outcomes.”
The study findings are limited by a number of factors, however, including the use of surrogate markers of poor asthma control and the omission of some confounding factors, such as tobacco exposure, living conditions, and ethnicity.
Writing in a linked Comment, Rachel Harwood from Alder Hey in the Park, Liverpool, says: “Careful decision-making around the delivery of the vaccine to children younger than 12 years is essential. Although children with asthma have been identified as having an increased risk of being admitted to hospital compared with peers without asthma, the overall risk remains very low. A balance between the risk of hospitalisation from SARS-CoV-2 and the low risk of vaccination side-effects needs to be carefully considered before vaccination is contemplated.”
She adds, “Over the coming winter, many well recognised respiratory viruses are anticipated in children, and in combination with seasonal changes, these are expected to increase the frequency and severity of asthma exacerbations. A focus on excellent asthma control, including the delivery of the influenza vaccine, and improving air quality and hygiene in schools is essential for all children with asthma to reduce their susceptibility to exacerbations over the coming winter.”