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Background: Allergic rhinitis affects half a billion people globally, including a fifth of the Australian population. As the foremost outdoor allergen source, ambient grass pollen exposure is likely to be altered by climate change. The AusPollen Partnership aimed to standardize pollen monitoring and examine broad-scale biogeographical and meteorological factors influencing interannual variation in seasonality of grass pollen aerobiology in Australia. Methods: Daily airborne grass and other pollen concentrations in four eastern Australian cities separated by over 1700 km, were simultaneously monitored using Hirst-style samplers following the Australian Interim Pollen and Spore Monitoring Standard and Protocols over four seasons from 2016 to 2020. The grass seasonal pollen integral was determined. Gridded rainfall, temperature, and satellite-derived grassland sources up to 100 km from the monitoring site were analysed. Results: The complexity of grass pollen seasons was related to latitude with multiple major summer-autumn peaks in Brisbane, major spring and minor summer peaks in Sydney and Canberra, and single major spring peaks occurring in Melbourne. The subtropical site of Brisbane showed a higher proportion of grass out of total pollen than more temperate sites. The magnitude of the grass seasonal pollen integral was correlated with pasture greenness, rainfall and number of days over 30 °C, preceding and within the season, up to 100 km radii from monitoring sites. Conclusions: Interannual fluctuations in Australian grass pollen season magnitude are strongly influenced by regional biogeography and both pre- and in-season weather. This first continental scale, Southern Hemisphere standardized aerobiology dataset forms the basis to track shifts in pollen seasonality, biodiversity and impacts on allergic respiratory diseases.

Background: Asthma epidemics associated with thunderstorms have had catastrophic effects 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 multicenter study recruited adults from Melbourne, Australia, with a past diagnosis of TA and/or self-reported SAR. Clinical information, spirometry results, white blood cell count, ryegrass pollen–specific (RGP-sp) IgE concentration, and fractional exhaled nitric oxide 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 of 228) reported SAR only (the I-SAR group), 37% (84 of 228) reported TA symptoms but had not attended hospital for treatment (the O-TA group), and 28% (64 of 228) had presented to the hospital for TA (the H-TA group). All patients in the H-TA group reported a previous asthma diagnosis. Logistic regression analysis of factors associated with O-TA and H-TA indicated that lower FEV1 value and an Asthma Control Questionnaire score higher than 1.5 were associated with H-TA. Higher blood RGP-sp IgE concentration, eosinophil counts, and fractional exhaled nitric oxide level were significantly associated with both O-TA and H-TA. Receiver operating curve analysis showed an RGP-sp IgE concentration higher than 10.1 kU/L and a prebronchodilator FEV1 value of 90% or lower to be biomarkers of increased H-TA risk. Conclusion: Clinical tests can identify risk of a history of TA in individuals with SAR and thereby inform patient-specific treatment recommendations.

Background: The most severe thunderstorm asthma (TA) event occurred in Melbourne on the 21st November 2016 and during this period, daily pollen information was available and accessible on smart devices via an App. An integrated survey within the App allows users to self-report symptoms. Objective: To explore patterns of symptom survey results during the period when the TA event occurred. Methods: Symptom data from the Melbourne Pollen Count and Forecast App related to asthma history, hay fever symptoms, and medication use was explored. A one-week control period before and after the event was considered. Chi-square tests and logistic regression were used to assess associations between sex, age, symptoms, and medication use. Results: Of the 28,655 responses, during the 2016 pollen season, younger (18 to 40 years) males, with no hay fever and no asthma were the most single and regular responders. During the TA event for new users, sex was only significantly associated with hay fever (p = 0.008) of which 60.2% of females’ responses reported having hay fever, while 43% of males’ responses did not. Those with mild symptoms peaked during the TA event. Conclusions: Many individuals completed the survey on the app for the first time during the TA event indicating the potential of digital technologies to be used as indicators of health risk among populations at risk of TA events.

Objective: The aim of this study was to quantify the direct and indirect costs of asthma and allergic rhinitis (AR) for 2018 in Tasmania. Methods: We used publicly available data, and Tasmanian-specific values where available, to estimate direct and indirect costs of both diseases. Direct costs included outcomes such as emergency department (ED) presentations, hospitalisations, general practice visits and medication use. Indirect costs included premature mortality and lost productivity. Results: Direct health impacts for both conditions combined included 1454 ED presentations, 682 hospitalisations, 72 446 general practice visits and 7122 specialist visits. Indirect health impacts included 13 deaths and between 483 000 and 2.8 million days of lost productivity. Total costs ranged between A126.5 million and A436.7 million for asthma and between A65.3 million and A259.7 million for AR. Per-person annual costs ranged between A1918 and A6617 for asthma and between A597 and A2374 for AR. Conclusions: The main financial burden due to asthma and AR was related to productivity losses from presenteeism and absenteeism. The magnitude of the economic impacts of AR and asthma warrants further analysis to produce a national-level assessment. Such analyses could identify cost-effective interventions that produce highest benefits for the management of these conditions in our community. What is known about the topic?: Allergic respiratory diseases, and particularly asthma and AR, pose a significant health burden, with effects including asthma-related hospital admissions, significant pharmaceutical expenditure and lost workforce and school education productivity. Australia, and particularly Tasmania, has a high prevalence of these conditions, but no recent studies have appraised or estimated their health impacts and costs. What does this paper add?: This paper proposes a unique and transparent costing model that allows the costs of these conditions to be estimated while accounting

Objective: Sudden acute episodes of asthma exacerbation are often treated by hospital EDs. It is hypothesised that determinants of acute asthma would differ across geographic regions. The objective of the present study was to detail seasonality, trends and spatiotemporal patterns of asthma ED presentations across Queensland (QLD), Australia, a state covering 1.8 million square kilometres, spanning multiple climates. Methods: Six years of routinely collected data (2012 to 2017) from 28 major QLD public hospitals were extracted from Queensland Health's Emergency Data Collection. The dataset contained individual, episode-level asthma-like diagnoses of ED presentations. Seasonality and trends of acute asthma were assessed through multiplicative time-series analysis. Results: The study consisted of 2192 days with a total of 65 012 asthma ED presentations in QLD. The 6-year average daily incidence rate was 270 asthma ED presentations per 100 000 population. The highest morbidity of asthma ED presentations occurred during the southern hemisphere winter months. Children showed a higher incidence rate compared to adults with males experiencing a higher incidence compared to females up until the age of 13, after which an inversion was observed persisting through adulthood. Seasonality of asthma ED presentations differed with latitude across QLD. Conclusion: Asthma-related ED presentations exhibit spatiotemporal variation across QLD, which appears to be related to climate. Furthermore, aeroallergens and respiratory viruses may be responsible for asthma ED peaks outside the winter period. Socioeconomic status may influence asthma ED presentation rates between regions. This knowledge can guide ongoing management and assist public health policy response.

Pollen exposure weakens the immunity against certain seasonal respiratory viruses by diminishing the antiviral interferon response. Here we investigate whether the same applies to the pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is sensitive to antiviral interferons, if infection waves coincide with high airborne pollen concentrations. Our original hypothesis was that more airborne pollen would lead to increases in infection rates. To examine this, we performed a cross-sectional and longitudinal data analysis on SARS-CoV-2 infection, airborne pollen, and meteorological factors. Our dataset is the most comprehensive, largest possible worldwide from 130 stations, across 31 countries and five continents. To explicitly investigate the effects of social contact, we additionally considered population density of each study area, as well as lockdown effects, in all possible combinations: without any lockdown, with mixed lockdown−no lockdown regime, and under complete lockdown. We found that airborne pollen, sometimes in synergy with humidity and temperature, explained, on average, 44% of the infection rate variability. Infection rates increased after higher pollen concentrations most frequently during the four previous days. Without lockdown, an increase of pollen abundance by 100 pollen/m3 resulted in a 4% average increase of infection rates. Lockdown halved infection rates under similar pollen concentrations. As there can be no preventive measures against airborne pollen exposure, we suggest wide dissemination of pollen−virus coexposure dire effect information to encourage high-risk individuals to wear particle filter masks during high springtime pollen concentrations.

Objective: Patient characteristics with exacerbation of asthma accessing care in the ED who are at risk of hospital admission have not been determined in subtropical climates. The objective of the study was to investigate the spatiotemporal burden of asthma hospital admissions across Queensland (QLD) and model risk factors for asthma hospital admission following an ED visit. Methods: Six years of routinely collected data (2012–2017) from 28 QLD public hospitals were extracted from Queensland Health's Emergency Data Collection. The dataset contained individual, episode-level ED presentations having asthma-like diagnoses, and an indicator of hospital admission, including to short-stay unit (SSU). A generalised additive model was used to examine the risk of asthma hospital admission. Results: Asthma hospital admissions increased from a weekly median of 79 (interquartile range [IQR] 66–99) in 2012 to 104 (IQR 81–135) in 2017. A higher incidence of asthma hospital admission was observed among males (median age 9, IQR 5–32) in childhood and females in adulthood (median age 32, IQR 11–51). Compared to the state capital Brisbane, the odds of asthma hospital admission ranged from 0.48 (95% CI 0.42–0.54) to 1.34 (95%CI 1.21–1.48) in other regions of QLD. Conclusion: Asthma hospital admissions appear to be increasing in QLD, largely driven by utilisation of the SSU admissions for asthma. With large variation in both incidence and proportion admitted across different regions, routinely collected data can in part be used to understand risk factors for asthma-related hospital admission following an ED presentation and further inform public health policy development.