Severe Respiratory Syncytial Virus Infection in Hospitalized Children Less Than 3 Years of Age in a Temperate and Tropical Climate

Abstract

Respiratory syncytial virus (RSV) infection is a frequent cause of hospitalization in infants younger than 3 years of age. We aimed to determine the factors associated with severe RSV disease. Retrospective medical review of children up to 3 years of age admitted for laboratory-proven RSV infection between January 1, 2013, and December 31, 2014, was conducted at the Women's and Children's Hospital, Adelaide, South Australia, and the Paediatric Department at Cairns Hospital, Cairns, North Queensland. Severity of infection was determined using the validated Brisbane RSV Infection Severity Score. Four-hundred ninety-six children (383 at Women's and Children's Hospital and 113 at Cairns Hospital) were included in the study, with 76, 323 and 97 patients identified as having mild, moderate or severe disease, respectively. Decreasing age [odds ratio (OR) = 0.95; 95% confidence interval (CI) = 0.90-0.99, P = 0.020), and being Indigenous, increased (OR = 2.6; 95% CI = 1.4-4.9, P = 0.002) the risk of severe RSV infection in hospitalized children. Underlying respiratory (P = 0.029, OR = 2.5; 95% CI = 1.1-5.8) or cardiac (OR = 2.7; 95% CI = 1.1-6.4, P = 0.024) conditions, as well as the presence of tachypnoea on admission (OR = 2.2; 95% CI = 1.2-4.1, P = 0.009), were also independent predictors of severe RSV infection. Seasonal variation in hospitalization was observed between temperate and tropical climates but was not associated with disease severity. Young infants, Indigenous patients and children with underlying respiratory and cardiac disease should be observed closely for signs of deterioration. Infants with tachypnoea on admission should be continuously monitored.