The Clinical Characteristics, Severity, and Seasonality of RSV Subtypes Among Hospitalized Children in Jordan.

Background Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infection (ARI) in young children worldwide. Multiple factors affect RSV disease severity, and data regarding differences between RSV subtypes severity are controversial. This study aimed to evaluate the clinical characteristics, seasonality and severity of RSV subtypes in children. Methods As part of a prospective ARI surveillance study conducted from March 2010 to March 2013 in Amman, Jordan, children less than 2 years with fever and/or respiratory symptoms were enrolled. Demographic and clinical characteristics were collected through parental interviews and medical chart review. The treating physician collected severity score data at admission. Nasal and throat swabs were collected and tested. Multivariable regression models were used to compare the odds of increased disease severity across a priori selected predictors of interest. Results Overall, 1397/3168 (44%) children were RSV positive, with a mean age of 5.3 months (±4.8 SD), 59.7% were male, 6.4% had an underlying medical condition (UMC), 63.6% were RSV-A positive, 25.2% were RSV-B positive, 0.6% were positive for both, and 10.6% could not be typed. Both RSV subtypes peaked in January-March of each year. RSV A-positive children were more likely to present with decreased appetite but less likely to have viral co-detection than RSV B-positive children. Independent factors associated with RSV disease severity included cycle threshold value, vitamin D level, age, UMC, prematurity and severity score, but not RSV subtypes. Conclusion RSV subtypes co-circulated and had similar severity profiles; future preventive and treatment measures should target both subtypes.