Seasonality and epidemiology of respiratory syncytial virus in Qatar

Respiratory syncytial virus (RSV) is the major cause of acute lower respiratory tract infections in early childhood. Annual epidemics occur which are well documented in developed countries during winter months, placing considerable pressure on the provision of health care. Little is known about the epidemiology of RSV infections in the Middle East and other desert climate regions of the world. The objective of this study was to determine the infection rate and seasonality of RSV among children 2 years old or younger and its correlation with meteorological data in Qatar. A retrospective descriptive hospital-based population study was conducted. Data of RSV infection detected from children at Pediatric Emergency Centre in the Hamad Medical Corporation, Doha, State of Qatar from January 2002 to September 2007, were collected. Meteorological data from Department of Civil Aviation were collected during the period of January 2002 - September 2007 and were used to determine the mean monthly temperature, relative humidity, evaporation, rainfall and wind speed. A total of 3121 children below 2 years of age were screened for a possible infection for RSV during the study period. 26.3% of the total children screened tested positive for RSV (infection rate) with the highest annual rate of 35.3% in 2003 and the lowest rate of 13.2% in 2007. RSV was found to be a major cause of hospital admission in children during the winter months of November - January every year. The peak of mean relative humidity significantly coincided with the peak of RSV infection rate (P = 0.0039 and r = 0.7682), and there was a significant inverse correlation between the monthly mean temperature and RSV infection (P = 0.0061 and r = -0.7384). The pattern of RSV infections showed a clear seasonality in that infections were mostly encountered during winter and after rainfall. Further studies should focus on the significance of RSV infections in other age groups or in other infections with other respiratory viruses.