Lung function in prematurely born infants after viral lower respiratory tract infections

Background: Chronic respiratory morbidity has been reported in prematurely born infants after respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) lower respiratory tract infections (LRTIs). The aim of this study was to determine the impact of viral LRTI on lung function at follow-up of prematurely born infants. Methods: Fifty-nine infants born before 32 weeks of gestational age were prospectively followed after neonatal unit discharge. Nasopharyngeal aspirates were obtained when the infants developed LRTIs in hospital or the community. RSV was identified by immunofluorescence and/or culture. In addition, RSV and other viral infections were identified by real time reverse transcription polymerase chain reaction. At a corrected age of 1 year, measurements of lung volume [functional residual capacity (FRC)(pleth)] and airway resistance (R-aw) were made by plethysmography, and lung volume was also assessed by helium gas dilution (FRCHe). Before the measurements, parents completed diary cards for I month documenting on a daily basis whether their infant wheezed, coughed, or required bronchodilator therapy. Results: Twenty-five infants had at least 1 proven RSV LRTI (RSV-positive group). The RSV-positive group compared with the rest of the cohort had similar lung volumes, but significantly higher R-aw (P = 0.002), more days of wheeze (P < 0.001). and bronchodilator requirement (P = 0.027). Regression analysis also identified that hMPV LRTI was associated with elevated airways resistance at follow-up. Conclusion: RSV and hMPV LRTIs in prematurely born infants are associated with abnormal lung function at follow-up.