Incidence, risk factors and hospital burden in children under five years of age hospitalised with respiratory syncytial virus infections.

Aim: Respiratory syncytial virus (RSV) infections are among the most common lower respiratory tract infections in infants, but few studies have determined the age-specific incidence of hospitalisation in defined populations. This study gathered Swedish data on RSV in Gothenburg and its 10 surrounding municipalities from 2004 to 2011.

Methods: Information was obtained from hospital databases of all patients up to five years of age who had a discharge diagnosis of an RSV infection and had a positive antigen detection or polymerase chain reaction test.

Results: A total of 1764 children fulfilled the inclusion criteria and 238 of these were preterm. The incidence under one year of age was 17.4/1000/year, and in children aged one to four years it was 0.6/1000/year. RSV patients occupied a mean of 1141 hospital beds per year: 65 were treated in the intensive care unit, 27 needed ventilator support, 19 needed continuous positive airway pressure, 408 (23%) received antibiotics, 399 (23%) received steroids, and all but four patients received a bronchodilator. All children survived.

Conclusion: The incidence of RSV infections was high, medication use was high, and complications were low. Preterm infants had a higher risk, but most infants needing hospitalisation for RSV are full term and have no known risk factors.