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Background Asthma epidemics associated with thunderstorms have had catastrophic impacts on individuals and emergency services. Seasonal allergic rhinitis (SAR) is present in the vast majority of people who develop thunderstorm asthma (TA), but there is little evidence regarding risk factors for TA among the SAR population. Objective We sought to identify risk factors for a history of TA and hospital presentation in a cohort of individuals with SAR. Methods This multi-centre study recruited adults from Melbourne (Australia) with a past diagnosis of TA and/or self-reported SAR. Clinical information, spirometry, white blood-cell count, ryegrass pollen specific IgE (RGP-spIgE) and fractional exhaled nitric oxide (FeNO) were measured to identify risk factors for a history of TA in individuals with SAR. Results From a total of 228 individuals with SAR, 35% (80/228) reported SAR only (I-SAR), 37% (84/228) reported TA symptoms but had not attended hospital for treatment (O-TA) and 28% (64/228) had presented to hospital for TA (H-TA). All H-TA patients reported a previous asthma diagnosis. Logistic regression analysis of factors associated with O-TA and H-TA indicated that lower forced expiratory volume in one second (FEV1) and asthma control questionnaire (ACQ) score >1.5 were associated with H-TA. Higher blood RGP-spIgE, eosinophil counts, and FeNO were significantly associated with both O-TA and H-TA. Receiver-operating curve (ROC) analysis showed RGP-spIgE >10·1 kU/L and pre-bronchodilator FEV1 ≤90% to be biomarkers of increased H-TA risk. Conclusion Clinical tests can identify risk for a history of TA in individuals with SAR and thereby inform patient-specific treatment recommendations.

BackgroundThe relationship between asthma and coronavirus disease 2019 (COVID-19) risk is not clear and may be influenced by level of airway obstruction, asthma medication and known COVID-19 risk factors. We aimed to investigate COVID-19 risk in people with asthma.MethodsWe used UK Biobank data from all participants tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (n=107 412; 17 979 test positive). Questions at baseline defined ever asthma and asthma medications. Baseline forced expiratory volume in 1 s (FEV1) was categorised into quartiles. Logistic regression modelled relationships between asthma, and asthma categories (age at onset, medications, FEV1 quartiles), and risk of SARS-CoV-2 positive test. We investigated modification by sex, ethnic group, smoking and body mass index.ResultsThere was a reduced risk of a positive test associated with early-onset asthma (ConclusionAmongst male, nonsmoking, overweight/obese and non-Black participants, having early-onset asthma was associated with lower risk of a SARS-CoV-2 positive test. We found no evidence of a protective effect from asthma medication. Individuals with early-onset asthma of normal weight and with better lung function may have lifestyle differences placing them at higher risk. Further research is needed to elucidate the contribution of asthma pathophysiology and different health-related behaviour, across population groups, to the observed risks.