This research looks at how breathing in pollen at different stages of life may influence the development and worsening of allergic diseases such as hay fever and asthma. It brings together two related studies to explore both long-term and short-term effects of pollen on the immune system.
The first part follows children from birth to see whether the amount of pollen they are exposed to during their first year of life is linked to developing allergies later on. This is a critical period when the immune system is still growing and may be more sensitive to the environment.
The second part looks at differences between those who have asthma and those who do not. It uses information from crowd-sourced smartphone symptom reports to understand how repeated days of high pollen levels may make symptoms worse. The focus is on how long and intense exposure affects the body’s response.
By combining these two studies, the research aims to give a clearer picture of how pollen contributes to allergic disease over time. The goal is to improve early prevention, help people manage symptoms, and support better public health advice during times of high pollen.
Research Outcomes
We examined how grass pollen exposure affects the risk and timing of hay fever symptoms across seven days following exposure. We also looked at whether risk and timing differ for more vulnerable groups such as people with asthma. The study analysed 114,834 symptom reports submitted by over 25,000 users of a smartphone app in Melbourne, Australia.
Symptom risk was mainly elevated on the day of exposure and, to a lesser extent, the following day. Even grass pollen concentrations traditionally classified as "low" were associated with a measurable increase in symptom risk. For most users, this increased risk was short lived and returned to baseline within two to three days.
Some groups were more affected. People with asthma and those reporting greater symptom burden exhibited more persistent risk, with patterns also differing by age and sex. These findings support improving pollen warnings and public health messages to better reflect symptom timing and individual susceptibility.
Research Impact
Invited to present findings from manuscript titled “Immediate and Lagged Hay Fever Symptom Burden from Grass Pollen: Implications for Public Health Warning Thresholds” at Metro South internal seminar series 5th August 2026.
