Five-year cohort study of hospitalization for respiratory syncytial virus associated lower respiratory tract infection in African children.

OBJECTIVES: To describe the epidemiology of respiratory syncytial virus (RSV) associated lower respiratory tract infection (RSV-LRTI) hospitalizations in South African children over a 5-year period, and determine the impact of gestational age (GA) on the incidence of RSV-LRTI hospitalization.

STUDY DESIGN: A cohort of 39,836 children, 6.47% of whom were HIV infected, enrolled into a phase 3 trial were prospectively studied for respiratory viruses when hospitalized for LRTI.

RESULTS: The incidence of hospitalization for RSV-LRTI was 19.4 per 1000 in HIV uninfected children and 2.5-fold (95% CI 2.04-3.03) greater in HIV infected children (45.0 per 1000). The incidence of RSV-LRTI was 4.9-fold greater (95% CI 3.9-6.8) in children born at <36 weeks of gestational age (GA) and repeat hospitalizations for RSV-LRTI was 3.7-fold (95% CI 1.4-9.4) more likely in these children (7.3%) than children born at > or =36 weeks of GA (1.9%). The burden of RSV-LRTI was greater in children born at <32 weeks of GA than those born at 32-35 weeks of GA between 6-12 months (P=0.008) and 12-24 months of age (P=0.001). The RSV epidemic occurred at the end of the rainy season and peaked when the monthly temperatures were at its lowest each year.