Risk of COVID-19 hospital admission among children with asthma
Authors: Rachel Harwood, Ian P Sinha
Journal: The Lancet Respiratory Medicine (2021)

Throughout the COVID-19 pandemic it has been clear that children are at substantially lower risk of severe disease than adults.1Zimmermann P Curtis N Why is COVID-19 less severe in children? A review of the proposed mechanisms underlying the age-related difference in severity of SARS-CoV-2 infections.Arch Dis Child. 2020; (published online Dec 1.)https://doi.org/10.1136/archdischild-2020-320338Crossref Scopus (298) Google Scholar Nevertheless, large groups of children with comorbidities have been asked to shield for long durations, forgoing their access to face-to-face education and reducing their social contact, with substantial potential detriment to their mental health and emotional wellbeing. Identification of subgroups of children with comorbidities at increased risk of severe disease compared with their counterparts has been much slower to become evident than in adults because of the low rates of severe disease. Asthma was recognised as a comorbidity that increases the risk of death and admission to hospital with COVID-19 in adults early in the pandemic.2Clift AK Coupland CAC Keogh RH et al.Living risk prediction algorithm (QCOVID) for risk of hospital admission and mortality from coronavirus 19 in adults: national derivation and validation cohort study.BMJ. 2020; 371m3731Crossref PubMed Scopus (383) Google Scholar Subsequently, asthma was identified as a comorbidity that increases the risk of severe disease (admission to critical care, receiving invasive ventilation, or death) in hospitalised children.3Kompaniyets L Agathis NT Nelson JM et al.Underlying medical conditions associated with severe COVID-19 illness among children.JAMA Netw Open. 2021; 4e2111182Crossref PubMed Scopus (248) Google Scholar, 4Ward JL Harwood R Smith C et al.Risk factors for intensive care admission and death amongst children and young people admitted to hospital with COVID-19 and PIMS-TS in England during the first pandemic year.medRxiv. 2021; (published online July 5.) (preprint).https://doi.org/10.1101/2021.07.01.21259785Google Scholar However, although deaths of children with asthma and SARS-CoV-2 infection have been reported, the deaths have been attributed to complex comorbidity rather than asthma as a sole diagnosis.5Smith C Odd D Harwood R et al.Deaths in children and young people in England after SARS-CoV-2 infection during the first pandemic year.Nat Med. 2021; (published online Nov 11.)https://doi.org/10.1038/s41591-021-01578-1Crossref Scopus (78) Google Scholar The study by Ting Shi and colleagues6Shi T Pan J Katikireddi SV et al.Risk of COVID-19 hospital admission among children aged 5–17 years with asthma in Scotland: a national incident cohort study.Lancet Respir Med. 2021; (published online Nov 30.)https://doi.org/10.1016/S2213-2600(21)00491-4Summary Full Text Full Text PDF Scopus (41) Google Scholar in The Lancet Respiratory Medicine is, to our knowledge, the first to use nationally representative linked data spanning primary care, community prescribing, hospital admissions, and deaths to provide a much more detailed insight into the risk of severe SARS-CoV-2 in children aged 5–17 years with asthma in Scotland. The findings from Shi and colleagues' study suggest that compared with children without asthma, the risk of admission to hospital with COVID-19 is increased in children with a diagnosis of asthma in their primary care records, particularly when they have previously been admitted to hospital with asthma (HR 6·40 [95% CI 3·27–12·53]) or have required two or more courses of oral corticosteroids (3·53 [1·87–6·67]) in the 24 months before the study start date (March 1, 2020).6Shi T Pan J Katikireddi SV et al.Risk of COVID-19 hospital admission among children aged 5–17 years with asthma in Scotland: a national incident cohort study.Lancet Respir Med. 2021; (published online Nov 30.)https://doi.org/10.1016/S2213-2600(21)00491-4Summary Full Text Full Text PDF Scopus (41) Google Scholar Shi and colleagues use a Cox regression model to study these associations. Although this method of analysis has been used in other studies, such as QCOVID,2Clift AK Coupland CAC Keogh RH et al.Living risk prediction algorithm (QCOVID) for risk of hospital admission and mortality from coronavirus 19 in adults: national derivation and validation cohort study.BMJ. 2020; 371m3731Crossref PubMed Scopus (383) Google Scholar the data in this study were collected over a substantially longer duration. This means that the severity of asthma described in the study relates to the 2 years before the pandemic and does not necessarily reflect changes in asthma control that occurred throughout the 16-month study period. The sensitivity analyses suggest that the strong associations observed between previous hospital admission and two or more courses of oral corticosteroids and admission to hospital with COVID-19 are robust, but temporal changes in the rate of admission to hospital are noted within the data. These changes are described according to the predominant SARS-CoV-2 variants (alpha [B.1.1.7] and delta [B.1.617.2]) where the difference in the rate of admission to hospital with COVID-19 between those with well controlled and poorly controlled asthma increased through the pandemic. However, additional variables such as changes in asthma control and rate of presentation to hospital during the study period have not been overtly considered and might influence the rate of admission to hospital as the pandemic progressed. The US Food and Drug Administration have recently approved licensing of the Pfizer-BioNTech COVID-19 vaccine for children aged 5–11 years and the US Advisory Committee on Immunization Practice now recommend the use of the vaccine in this age group.7Food and Drug AdministrationFDA authorizes Pfizer-BioNTech COVID-19 vaccine for emergency use in children 5 through 11 years of age.https://www.fda.gov/news-events/press-announcements/fda-authorizes-pfizer-biontech-covid-19-vaccine-emergency-use-children-5-through-11-years-ageDate accessed: November 3, 2021Google Scholar, 8Woodworth KR Moulia D Collins JP et al.The Advisory Committee on Immunization Practices' interim recommendation for use of Pfizer-BioNTech COVID-19 vaccine in children aged 5–11 years—United States, November 2021.MMWR Morb Mortal Wkly Rep. 2021; 70: 1579-1583Crossref PubMed Google Scholar The findings of Shi and colleagues' study might be used to identify children in this age range who would benefit most from early receipt of the vaccine. It is particularly interesting to note that this study finds that children with asthma aged 5–11 years without previous hospital admission for asthma and without previous courses of oral corticosteroids have an increased risk of admission to hospital with COVID-19, compared with children without asthma.6Shi T Pan J Katikireddi SV et al.Risk of COVID-19 hospital admission among children aged 5–17 years with asthma in Scotland: a national incident cohort study.Lancet Respir Med. 2021; (published online Nov 30.)https://doi.org/10.1016/S2213-2600(21)00491-4Summary Full Text Full Text PDF Scopus (41) Google Scholar The study design results in the youngest of children not receiving corticosteroids or being admitted to hospital with asthma before entering the study due to the diagnostic criteria for asthma.9Global Initiative for AsthmaGlobal strategy for asthma management and prevention.https://ginasthma.org/wp-content/uploads/2021/05/GINA-Main-Report-2021-V2-WMS.pdfDate accessed: November 3, 2021Google Scholar However, this might not reflect their subsequent asthma control during the study period and the data for this youngest group of children should be treated with caution. Within this country-wide study, only 67 (1·5%) of 4339 children with asthma and confirmed SARS-CoV-2 infection were admitted to hospital and nine were admitted to the intensive care unit or died with COVID-19, a remarkably small number.6Shi T Pan J Katikireddi SV et al.Risk of COVID-19 hospital admission among children aged 5–17 years with asthma in Scotland: a national incident cohort study.Lancet Respir Med. 2021; (published online Nov 30.)https://doi.org/10.1016/S2213-2600(21)00491-4Summary Full Text Full Text PDF Scopus (41) Google Scholar 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. 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.9Global Initiative for AsthmaGlobal strategy for asthma management and prevention.https://ginasthma.org/wp-content/uploads/2021/05/GINA-Main-Report-2021-V2-WMS.pdfDate accessed: November 3, 2021Google Scholar 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. RH is in receipt of a KRUK Fellowship (TF _010_20171124). IS declares no competing interests. Risk of COVID-19 hospital admission among children aged 5–17 years with asthma in Scotland: a national incident cohort studySchool-aged children with asthma with previous recent hospital admission or two or more courses of oral corticosteroids are at markedly increased risk of COVID-19 hospital admission and should be considered a priority for vaccinations. This would translate into 9124 children across Scotland and an estimated 109 448 children across the UK. Full-Text PDF Open Access