The relationship of meteorological conditions to the epidemic activity of respiratory syncytial virus

Abstract

Our aim was to obtain knowledge of how meteorological conditions affect community epidemics of respiratory syncytial virus (RSV) infection. To this end we recorded year-round RSV activity in nine cities that differ markedly in geographic location and climate. We correlated local weather conditions with weekly or monthly RSV cases. We reviewed similar reports from other areas varying in climate. Weekly RSV activity was related to temperature in a bimodal fashion, with peaks of activity at temperatures above 24-30 degrees C and at 2-6 degrees C. RSV activity was also greatest at 45-65% relative humidity. RSV activity was inversely related to UVB radiance at three sites where this could be tested. At sites with persistently warm temperatures and high humidity, RSV activity was continuous throughout the year, peaking in summer and early autumn. In temperate climates, RSV activity was maximal during winter, correlating with lower temperatures. In areas where temperatures remained colder throughout the year, RSV activity again became nearly continuous. Community activity of RSV is substantial when both ambient temperatures and absolute humidity are very high, perhaps reflecting greater stability of RSV in aerosols. Transmission of RSV in cooler climates is inversely related to temperature possibly as a result of increased stability of the virus in secretions in the colder environment. UVB radiation may inactivate virus in the environment, or influence susceptibility to RSV by altering host resistance.

Sunshine, rainfall, humidity and child pneumonia in the tropics: time-series analyses

“…In tropical settings lower respiratory infections in children are generally found to be more common during periods of higher rainfall and humidity, consistent with our results [7][8][9][10][11] . Rainfall is not convincingly associated with pneumonia incidence in time series studies from temperate settings 10,12,13 .…”

“…Less evidence examining the association of respiratory infection and sunlight exists from tropical settings. In the subtropical setting of Florida, weekly RSV incidence was inversely correlated with weekly UVB radiance, consistent with our results 10 . In contrast time series analyses from Hong Kong and Singapore found no significant association between solar radiation and the incidence of RSV 6, 9, 11 .…”

“…Increased relative humidity was associated with increased IPD incidence in New Zealand, but not in Australia 12, 13 . Low sunlight and temperature are consistently associated with high pneumonia incidence in time series studies in temperate settings, where annual peaks of lower respiratory infections occur during the short days of winter 10,[12][13][14][15][16] . The association between temperature and respiratory infections in children is inconsistent in time series studies from tropical settings, suggesting temperature is unlikely to be an important driver of pneumonia incidence in the tropics [6][7][8][9][10][11] .…”

“…Respiratory syncytial virus (RSV) infections were positively correlated with the number of rainy days and relative humidity in Indonesia and Malaysia, positively correlated with relative humidity and dew point in Mexico, and positively correlated with relative humidity in Hong Kong, although in Singapore a negative correlation with relative humidity was found [6][7][8][9][10][11] . In temperate settings where pneumonia peaks in winter, time series analyses have consistently found peaks of RSV and invasive pneumococcal disease (IPD) to be inversely correlated with temperature and daylight hours 10,[12][13][14][15][16] . Although daylight hours vary less in tropical latitudes, sunshine hours can vary seasonally according to cloud cover (and hence are generally lowest in the rainy season).…”

Predicción de la epidemia del virus respiratorio sincitial en Bogotá D.C. utilizando variables climatológicas

“…Para seleccionar las variables climatológicas se revisaron varios trabajos de otros autores, en los cuales se tomaron en cuenta diversas variables climatológicas (15)(16)(17). Se seleccionaron las investigaciones que reportaban un efecto positivo o negativo en la relación entre la actividad del RSV y las condiciones meteorológicas.…”