The association between respiratory viruses and symptoms in 2-week-old infants at high risk for asthma and allergy

Objectives: The role of viral respiratory tract infections in the onset of childhood asthma and allergy is controversial, partly because of limited un derstanding about postnatal viral exposures. We investigated the prevalence of 3 common respiratory viruses and associated respiratory symptoms in 2-w eek-old infants at high risk for having asthma and allergy. Study design: Frozen nasal specimens from 2-week-old children at high risk (n = 495) underwent reverse transcription-polymerase chain reaction (RT-PCR ) for picornavirus-, parainfluenza-, and respiratory syncytial virus-specif ic nucleic acid. RT-PCR findings were related to respiratory symptoms (cold , cough, and wheeze) and to characteristics implicated with increased risk for asthma and allergy. Results: Viral RT-PCR was positive in 199 (40.2%) of 495 specimens examined , with picornavirus and parainfluenza significantly associated with respira tory symptoms. Viral prevalence was significantly higher in children born d uring the winter and summer months. Conclusions: A high percentage (40.2%) of infants at high risk for asthma a nd allergy had been exposed to common respiratory viruses at 2 weeks of age . RT-PCR is a powerful diagnostic method that can be used in epidemiologic studies examining the role of viral respiratory tract infections in the pat hogenesis of pediatric asthma and allergy.