Seasonality and regional variation of respiratory syncytial virus-associated hospital admissions in northern Western Australia, 2012-2023.

OBJECTIVE

The aim of this study was to compare the seasonality of respiratory syncytial virus-associated hospital admissions in northern tropical Western Australia (Kimberley and Pilbara regions) to southern temperate Western Australia.

METHODS

We conducted an ecological study with linear modelling, utilising International Classification of Diseases, 10th version, Australian modification diagnostic coding to identify respiratory syncytial virus-associated hospital admissions from 2012 to 2023 across Western Australia.

RESULTS

We showed that respiratory syncytial virus-associated hospital admissions in southern temperate Western Australia followed a winter seasonality with the peak of the season typically in July to August. The Pilbara also generally followed a winter seasonality of respiratory syncytial virus-associated hospital admission rates. However, the Pilbara showed greater yearly variability and a longer duration of activity than southern temperate Western Australia. The Kimberley showed both higher rates of respiratory syncytial virus-associated hospital admissions and no clear seasonal patterns, with monthly and yearly variation compared to southern temperate Western Australia.

CONCLUSIONS

Seasonal variation of respiratory syncytial virus-associated hospital admissions is seen in both the Kimberley and Pilbara regions compared to southern temperate Western Australia.

IMPLICATIONS FOR PUBLIC HEALTH: The distinct seasonal variation in the northern regions of Western Australia should be considered when planning and implementing respiratory syncytial virus immunisation programs.