The epidemiology of respiratory syncytial virus: A retrospective review from Steve Biko Academic Hospital 2013 - 2016

BACKGROUND: Respiratory syncytial virus (RSV) bronchiolitis is a seasonal disease that has an enormous burden on health systems across the world. RSV disease manifestations in children range from mild upper respiratory tract infections to severe lower respiratory tract infections, including pneumonia and bronchiolitis. In South Africa, the seasonality of RSV disease causing both upper and lower respiratory tract illness is well documented. OBJECTIVES: To describe the incidence of RSV bronchiolitis among patients ≤24 months of age who presented to a tertiary institution with a diagnosed viral bronchiolitis over a 4-year period. Secondary aims included determining: (i) the risk factors for the development of RSV bronchiolitis; (ii) the fatality rates and risk factors associated with mortality; (iii) the correlation with c-reactive protein values and risk of comorbid bacterial infection; and (iv) the impact of seasonality on RSV incidence. METHODS: A retrospective chart-based analysis of laboratory-confirmed RSV cases in children ≤24 months, presenting to Steve Biko Academic Hospital from January 2013 to December 2016, was undertaken. Epidemiology, risk factors and local weather data were collected as part of the analysis. RESULTS: During the 4-year period, a total of 1 127 nasopharyngeal aspirates (NPAs) was collected. RSV was isolated from 162 NPAs by either immunofluorescence (84%) or polymerase chain reaction (16%). Of the 162 patients with RSV bronchiolitis, 131 (80.9%) had a known HIV status. Only 2 (1.5%) of the patients whose status was known were HIV-infected; 26 (19.8%) were HIV-exposed and confirmed negative; and 103 (78.6%) HIV-unexposed. Forty-nine patients (30.2%) with RSV required intensive care unit (ICU, either paediatric or neonatal) admission. Thirty-four (69.4%) of these were <6 months old. Prematurity (27.8%) and cardiac lesions (13%) were the most common risk factors for acquiring the disease identified in patients with RSV bronchiolitis. CONCLUSION: RSV is still a commonly detected virus among infants who are admitted for bronchiolitis. Significant risk factors associated with admission due to RSV bronchiolitis were prematurity, being <6 months of age and congenital cardiac disease. Male gender and HIV status did not appear to increase the risk of RSV bronchiolitis. In fact, HIV seems to have a protective effect against specifically RSV bronchiolitis in children <2 years of age. Young babies, especially premature infants with RSV bronchiolitis, are at considerable risk of requiring ICU admission, which leads to a significant increase in admission costs.