Climatic, temporal, and geographic characteristics of respiratory syncytial virus disease in a tropical island population

Abstract

Respiratory syncytial virus (RSV) is an important cause of morbidity in children worldwide, although data from equatorial regions are limited. We analysed climatic, spatial, and temporal data for children presenting to hospitals in Lombok island, Indonesia with clinical pneumonia. During the study period, 2878 children presented and 741 RSV cases were identified. In multivariate analysis with an 8-day lag, occurrence of rain was associated with 64% higher incidence of RSV disease [incidence rate ratio (IRR) 1.64, 95% confidence interval (CI) 1.13-2.38]. A 1% rise in mean relative humidity and 1 degree C increase in mean air temperature was associated with a 6% (IRR 1.06, 95% CI 1.03-1.10) and 44% (IRR 1.44, 95% CI 1.24-1.66) increase in RSV cases, respectively. Four statistically significant local clusters of RSV pneumonia were identified within the annual island-wide epidemics. This study demonstrates statistical association of monsoon-associated weather in equatorial Indonesia with RSV. Moreover, within the island-wide epidemics, localized RSV outbreaks suggest local factors influence RSV disease.

Fig. 1

Number of respiratory syncytial virus (RSV) cases per day, rain days in the corresponding week, daily amount of rain (mm), mean daily relative humidity (RH) (%), and mean daily air temperature (°C). Smoothing for RSV cases, daily amount of rain, mean daily RH, and mean daily air temperature performed by computing a moving average including 6 days before and 6 days after each day in the time series.

Fig. 2

Village (pustu) health centres included in statistically significant space–time clusters. Lombok, Indonesia, 1 January 2000 to 31 December 2002.