Abstract :
Purpose
Respiratory syncytial virus (RSV) is a major cause of morbidity in infants. Data from a Canadian prospective cohort study on risk factors for RSV hospitalization were used to assess the impact of RSV hospitalizations on subsequent morbidity and mortality in infants born at 33 to 35 weeks gestation.
Methods
This was a case–control analysis conducted within a cohort of 1857 infants born at 33 to 35 weeks gestation in Canada during two consecutive RSV seasons (2001–2002). There were 96 cases with confirmed (n = 66) or probable RSV (n = 30) hospitalization. Controls (n = 96) were infants in the cohort that did not have RSV and were matched to cases for gestation, small for gestational age, gender, and presence of chronic conditions at discharge after birth, as well as for daycare attendance, maximum number of people in the house, maximum number of smokers, breast feeding, and siblings under 5 years old attending daycare. Follow-up was from the date of discharge after birth to 1 month after the end of the local RSV season (mean: 4.4, range: 1–9 months). Measures of health care utilization and morbidity for the RSV cases were ascertained subsequent to the index RSV hospitalization and for the controls subsequent to discharge after birth.
Results
Compared with matched controls, infants with a confirmed RSV-positive hospitalization (n = 66) had significantly higher rates of emergency room visits (RR = 3.7; P = 0.033) and respiratory tract episodes (RR = 2.15; P < 0.001), and increased risk for rehospitalization after the RSV episode (RR = 12.35; P = 0.093). Infants hospitalized for positive or probable RSV (n = 96) had significantly higher rates of emergency room visits (RR = 3.52; P = 0.004) and respiratory tract episodes (RR = 2.41; P < 0.001), and increased risk for rehospitalization (RR = 3.51; P = 0.045).
Conclusion
RSV hospitalizations in 33- to 35-week-gestation infants are associated with a significant increase in morbidity and health care resource utilization subsequent to and not including those for the RSV infection. Consideration of these outcomes is essential in evaluating benefit of prophylaxis against RSV.
