Incidence and burden of respiratory syncytial virus infection in a community-based cohort o under-five years children in Nigeria.

Abstract

"Respiratory syncytial virus (RSV) is one of the most common causes of lower respiratory tract infection (LRI) in children under 5 years. Most of the available epidemiological information on RSV infection are from developed countries where denominator based studies have been done. We hereby describe our findings in a WHO sponsored study that estimated the incidence of the RSV infection in children in urban and rural communities in Nigeria. The study was designed as a prospective, population-based cohort of under-five children in an urban (Eleta) and a rural (Ijaiye) community in Oyo State, Nigeria. Nasopharyngeal wash was collected from each child with LRI into sterile plain 5mls tubes and transported daily to the laboratory on ice. An aliquot of each specimen was tested for presence of RSV antigen using an EIA and another aliquot inoculated into Hep2 cell line for virus isolation. Data analyses were performed using the EPIINFO version 6.0. Frequencies were compared using chi-square test at 95% confidential level and incidence reported as per 1000 child years.

A total of 2,015 children were enrolled for the study among which 413 episode of LRI occurred. The overall incidence of RSV associated LRI during the 2 years of follow-up was 125/1000 child years. The incidence of RSV in Ijaye was 1.6 times (CI, 0.31 – 1.2) and 1.9 times (CI, 0.9 – 3.6) higher than that of Eleta in the first year and second year respectively. The highest incidence of RSV infection occurred among the age group 3-5 months in Eleta and the age group 9-11 months in Ijaiye. No gender preponderance in the incidence of RSV was observed.

This study provided for the first time, a denominator based prevalence and incidence of RSV at the community level in Nigeria. The rates of RSV among under-five children in rural and urban communities in Nigeria are high."