D2.512 - Analysis of temporal and regional trends in Internet searches for pollen allergies (MELIUS)

Pollen allergies are among the most common allergic diseases in Germany and are becoming increasingly significant in the context of climate change. New methods are being used to better understand disease activity and health behavior at the population level. One promising approach is the use of crowdsourced data, such as internet search data. The aim of this study is to use this data to record and compare regional differences in allergic diseases between the 16 federal states and at the city level.

Internet searches on the topic of pollen allergies (e.g., “hay fever”) were identified and recorded for all 16 federal states and 21 selected cities in Germany (March 2020 - March 2024). The search terms were analyzed according to their search volume and normalized to 100,000 inhabitants for regional comparability.

This was followed by an analysis of the temporal trends in search volume. The presented data is part of a more comprehensive study.

Initial analyses reveal seasonal patterns and indicate that interest in terms such as “pollen allergy” increases primarily in spring and summer, when pollen counts from early bloomers and grasses are at their highest. The analyses also revealed significant regional differences in search behavior. The highest search volumes were found in the federal states of Hamburg, Bremen and Saarland, while Saxony-Anhalt, Saxony, and Thuringia had the lowest values. Overall, there was a statistically significant difference, with higher search activity in western German federal states compared to eastern German federal states (χ²(16) = 41.81; p < 0.001). Statistically significant differences were also found at the city level (χ²(23) = 106.94; p < 0.001): Kassel, Stuttgart, and Freiburg im Breisgau had the highest search volume values, while Berlin, Bremen, and Leipzig had the lowest.

Regional differences in search volumes for allergic diseases indicate different information-seeking behavior among the population. The analysis shows that digital search queries can be used to describe regional patterns in interest in health topics.