Long-term airway morbidity following viral LRTI in early infancy: recurrent wheezing or asthma?
Episodes of lower respiratory illnesses (LRIs) in the first years of life have been associated with recurrent wheeze in studies of high-risk and community-based cohorts. Respiratory syncytial virus (RSV) is an agent especially associated with severe cases of bronchiolitis affecting young infants in winter months and has a typical seasonal pattern. Data from the Children's Respiratory Study from Arizona and a hospital-based Swedish study have been interpreted as evidence that severe RSV bronchiolitis is associated with a 30-40% likelihood of subsequent asthma. Other respiratory viruses, especially Rhinovirus, have been identified to be importantly associated with recurrent wheeze in children at risk for asthma. A case-control study of palivizumab given in the first year of life to preterm infants has shown a 50% reduction in the occurrence of recurrent wheeze even after controlling for potential confounding variables. Prospective trials with anti-viral strategies, including potential new vaccines, should give us better understanding of the role of viral infections in early life in the causation of childhood asthma.
Stein
Renato T
RT
Departamento de Pediatria, Faculdade de Medicina, Pontificia Universidade Catolica, Porto Alegre, Brazil. rstein@pucrs.br
D001249:Asthma / Q000453:epidemiology* / Q000209:etiology; D001988:Bronchiolitis / Q000150:complications* / Q000821:virology; D006801:Humans; D007223:Infant; D009017:Morbidity / Q000639:trends; D011379:Prognosis; D012008:Recurrence; D012135:Respiratory Sounds / Q000209:etiology*; D018357:Respiratory Syncytial Virus Infections / Q000150:complications* / Q000821:virology; D013997:Time Factors