The inportance of respiratory syncytial virus (RSV) as a pathogen for acute lower respiratory tract infections in young children has been evaluated in a series of studies undertaken in The Gambia, West Africa. During the years 1993 to 1996, RSV occurred in yearly outbreaks in the rainy season. Mainly young children were affected, but the age distribution varied between years (median ages 3, 7, 8, and 5 months in the 4 years respectively). The estimated annual incidence of RSV infection leading to admission to hospital was 2.3% for children under 1 year of age; the proportion of all ALRI admissions due to RSV 19%.
In a case control study of potential risk factors for severe RSV infection, it was found that cases came from larger or more crowded households than controls; risk was particularly associated with larger numbers of children in the age group 3-5 years living in the extended household. Cases more frequently had a sibling who had died than controls. Controls were more likely to have been exposed to smoke from cooking fires than cases. Other protective factors were father’s nationality and profession. Vegetables were included in the diet of controls more frequently than in the diet of cases. The number of asthmatic mothers was small in both groups.
In a prospective cohort study which compared RSV-ALRI cases with 2 control cohorts, it was found that the incidence of pneumonia was approximately 3% times higher in cases than in controls. For wheezing, the rate was 7 times higher, but wheezing was less common than pneumonia. At 3 years of age, pneumonia and wheezing were uncommon in all groups. Incidence rates of ALRI were approximately twofold higher in the wet season than in the dry season.
In conclusion, RSV is an important cause of ALRI leading to hospital admission in the Gambia. Acute and subsequent morbidity is considerable, so prevention by vaccination would be worthwhile
