1478Extreme daily numbers of general practice encounters of asthma and allergic rhinitis in Australia

Background Asthma affects approximately 11% of Australia’s population and allergic rhinitis 19%. Grass pollen is associated with asthma and allergic rhinitis exacerbations. This study tested the hypothesis that days with extreme numbers of general practice (GP) encounters for asthma and allergic rhinitis aligned with grass pollen season. Methods The MedicineInsight GP database contains longitudinal data on persons attending a sample of Australian GPs. We created time series of daily counts of asthma and allergic rhinitis encounters by state and territory to identify extreme encounter days; days with counts above the 99th percentile. Results Of 3,036,678 attendances during the study period, 2.4% were for asthma. There were 83 extreme encounter days during April to December, across Australia. Victoria and South Australia had the highest increase in attendances on extreme days. Allergic rhinitis encounters represented 0.9% of attendances. Of the 69 extreme allergic rhinitis encounter days across Australia, Victoria and Australian Capital Territory had the highest increase in attendances. Allergic rhinitis extreme days were clustered between mid-October and early December (72%), compared to 22% of the asthma extreme days. Conclusions Extreme asthma GP encounters were not as strongly associated with grass pollen season compared to allergic rhinitis encounters. Victoria had a high number of encounters on asthma and allergic rhinitis extreme days, many associated with thunderstorm asthma. Key messages Extreme asthma encounter days can be associated with cooler months, grass pollen season and school holidays. Extremes allergic rhinitis presentation days were aligned with grass pollen season.

1250Grass pollen exposure and children’s asthma repeat admissions in Victoria, Australia

Background Paediatric asthma-related readmissions significantly challenge public health systems. As evidence suggests readmissions are possibly associated with ambient grass pollen levels, we sought to determine the relationship between grass pollen exposure and the risk of readmission for asthma among children in Victoria, Australia. Methods The Victorian Admitted Episodes Dataset 1st July 1997–30th June 2009 was used to identify primary admissions with a principal diagnosis of asthma for children aged 2-18 years. Total sample size was 48,068 admissions. Readmissions were defined as a subsequent admission within 28 days of index discharge. Multiple semi-parametric Poisson Generalized Additive Models were used to assess associations between the grass pollen season and daily grass pollen counts (lagged and cumulative) with repeat admissions, while controlling for meteorological factors and air pollutants. Results Readmissions totalled to 2,152 (4.47% of all admissions). Mean daily readmissions were 1.44 times higher during the grass pollen season (95%CI 1.03-2.02). Pollen season was associated with readmission only for the youngest age group (2-5), incident rate ratio 1.99 (95%CI 1.26-3.14). Daily readmission was non-linearly associated with same day pollen counts only for the 13-18-year age group. Lag 2 pollen counts were non-linearly associated with all daily readmissions for boys in gender-stratified and younger age groups (2-5, 6-12) in age-stratified analysis. Conclusions Grass pollen exposure was associated with higher readmission rates for paediatric asthma. Key messages Younger children and boys with severe or poorly controlled asthma need to be assessed for preventive therapies before the grass pollen season to reduce the repeat admissions.

Face masks suitable for preventing COVID-19 and pollen allergy. A study in the exposure chamber

Summary Background Since the outbreak of the coronavirus pandemic, the population in Germany has been asked to wear face masks in public areas. The masks are accepted by the public. People with a pollen allergy have an interest in knowing whether masks can also provide protection against pollen and thus prevent symptoms even without medication. Method In order to evaluate the potential ‘antipollen effect’ of face masks, 14 adults with confirmed grass pollen-induced allergic rhinoconjunctivitis were exposed to grass pollen for a period of two hours following a standardised protocol. The test was conducted outside of the grass pollen season. The subjects wore either no mask, a medical mask or a FFP2 mask. Results Subjects wearing either mask were clearly able to avoid both nasal and conjunctival symptoms. There were no significant differences between the two masks in terms of effect. Mask wearing to prevent pollen exposure clearly supports overall well-being. Conclusion Wearing a mask during pollen season can be recommended as an effective nondrug option for people with a pollen allergy.

The Patient's Hay-fever diary: users feedback can improve pollen information

<p><em>Background: </em>Pollen information is crucial for effective preventive behaviour of pollen allergy sufferers. In addition to the results of pollen monitoring and weather conditions, feedback from allergic people plays an important role in generating information for the public. A useful tool that gives us an insight into the burden of pollen allergy is the patient’s hay fever diary (PHD), developed by the Vienna Medical University. PHD is freely available online, users enter their location, general well-being, pollen symptoms and medication use.</p><p><em>Methods: </em>This study is based on two databases: 1- PHD data for symptom load index (SLI) calculations, only daily entries from Slovenia were used; 2- National pollen database for three measuring stations: Ljubljana, Maribor and Izola. A five-year period (2014-2018) was analysed. We reviewed the number of monthly entries as an indicator of the time span when most people need pollen information. The focus was on three high allergenic pollen types; birch (Betula), grass (Poaceae) and ragweed (Ambrosia). Annual pollen load (APL) allows us to compare results between years.</p><p><em>Results:</em> 60 % of yearly entries were recorded from March to May, when users reported the most problems with pollen-induced symptoms. In parallel the monthly pollen totals were high. Birch pollen season typically occurs from late March to end of April with May marked by grass pollen season. The highest SLI values were calculated for birch pollen (4,79 – 7,68), with the maximum in the year 2016 when the highest APL was also recorded. SLI for grass pollen season varied from 3,92 to 4,80 and is mostly lower than SLI for birch. SLI slowly decreased after May and rose again in August and September, when ragweed pollen occurs. Results for this non-native species show that SLI was increasing from 2,48 (2014) to 4,55 (2018).</p><p><em>Conclusion:</em> Pollen information is most sought after in the spring, when the highest daily concentrations are recorded. Birch pollen seems to have the highest impact on allergy sufferers, followed by grasses. In the case of ragweed we have noticed that the impact on health was increasing during the analyzed period. A comparison of the calculated SLI with the level of exposure to different pollen types may explain the fluctuations in the occurrence of allergic disease during the course of pollen seasons. Preventive behaviour of allergic persons is only possible with quick and accurate pollen information. Therefore, we started releasing preliminary results with a three-color scale to keep the public informed about the current state of allergens in the atmosphere.  </p>

Predicting the severity of the grass pollen season and the effect of climate change in Northwest Europe

Allergic rhinitis is an inflammation in the nose caused by overreaction of the immune system to allergens in the air. Managing allergic rhinitis symptoms is challenging and requires timely intervention. The following are major questions often posed by those with allergic rhinitis: How should I prepare for the forthcoming season? How will the season’s severity develop over the years? No country yet provides clear guidance addressing these questions. We propose two previously unexplored approaches for forecasting the severity of the grass pollen season on the basis of statistical and mechanistic models. The results suggest annual severity is largely governed by preseasonal meteorological conditions. The mechanistic model suggests climate change will increase the season severity by up to 60%, in line with experimental chamber studies. These models can be used as forecasting tools for advising individuals with hay fever and health care professionals how to prepare for the grass pollen season.