Short-term Effects of Weather on Hand, Foot, and Mouth Disease

O-31B1-6 Background/Aims: Since late 1990s, there have been increasing hand, foot, and mouth disease (HFMD) outbreaks with complications leading to death, especially in Asia. The outbreaks of HFMD peak in the warmer season of the year, but the underlying factors for this upsurging trend have not yet been established. This study analyzes how weather variables influence the risk of HFMD incidence in Singapore. Methods: The relative risks between weekly HFMD and weekly temperature and rainfall were estimated for the period 2001–2008 using time series Poisson regression models. Smoothing was used to allow non-linear relationship between weather and weekly counts of HFMD. Models were adjusted for seasonality, long-term time trends, autocorrelation, and allowed for delays between exposures and the resulting effects. Results: Short-term changes in weekly temperature and rainfall influence HFMD incidence at time lag of 1–2 weeks. Inverse relationship is established between HFMD incidence and minimum temperature. Nevertheless, every 1° increase in maximum temperature above 32°C and temperature difference greater than 7°C elevates relative risk of HFMD incidence by 45% and 48%, respectively. Simultaneously, weekly cumulative rainfall ranging from 0 to 75 mm poses relative risk of HFMD. Conclusion: Weather parameters could possibly be used as risk indicators to alert local authority and community for potential HFMD outbreaks; thus, allows early response to strengthen infection control measures and promotes community preparedness to disrupt chain of disease transmission. Similar studies considering spatiotemporal risk heterogeneity are encouraged to further understand the effects of weather or climate variability on HFMD transmission patterns.