Meteorological drivers of respiratory syncytial virus infections in Singapore

Abstract

Background: Meteorological drivers are known to affect the transmissibility of respiratory viruses, including respiratory syncytial virus (RSV), but there are few studies quantifying the role of these drivers. Methods: We used daily RSV hospitalization data to estimate the daily effective reproduction number (R_t), a real-time measure of transmissibility, and examined its relationship with environmental drivers in Singapore during 2005-2015. We used multivariable regression models to quantify the proportion of the variance in R_t explained by each driver by comparing these improved models over basic model (including depletion of susceptible and inter-seasonal effects). Results: We estimated R_t for 11 epidemics with median value 1.03 (95% CI: 0.66, 1.52), and lies between the highest value 2.32 (95% CI: 1.03, 4.39) at the start of epidemic and lowest value 0.40 (95% CI: 0.21, 0.67). A considerable proportion of the variance explained by the intrinsic factors in the basic model, the meteorological drivers explained a further 15% of the variance in transmissibility for RSV circulation. While higher mean temperature and diurnal temperature range (DTR) were associated with increased RSV transmissibility, higher maximum wind speed and precipitation were correlated with decreased transmissibility. The time series of mean temperature, DTR, maximum wind speed and precipitation could explain a maximum of 3.40%, 2.29%, 4.85% and 4.13% of the variance in R_t respectively. Conclusions: We found that meteorological drivers were associated with RSV transmissibility. The negative association of maximum wind speed on transmissibility indicates the virus might circulate more in lower wind flow. Further lower DTR was associated with lower RSV transmissibility, indicates the shorter temperature range during short period may affect the virus on limiting the spread. These findings could help to predict surges in community RSV incidence as well as inform the design of ventilation features especially in hospital settings to mitigate nosocomial transmissions.