Viral Inception of Asthma: Prospective Study From Infancy to School-age

The purpose of this study is to study prospectively the early clinical and immunological events in children susceptible to rhinovirus induced early wheezing (i.e., recently found highest risk factor for recurrent wheezing/asthma) and the efficacy of systemic corticosteroid to modify these events. Up to 50% of children suffer from acute wheezing before school-age. The prevalence of childhood asthma is 5-7%. Although pediatric asthma is mainly allergic, the exacerbations are associated with respiratory viral infections in 95% of cases. The means to predict asthma from environmental factors have been limited mainly to sensitization to aeroallergens (3-fold risk), which start to develop usually at 2-3 years of age. VINKU 1-study (orig. VINKU-study) discovered simultaneously with two other groups, that early wheezing associated with rhinovirus, the "common cold" virus, is the strongest predictor of recurrent wheezing/asthma (up to 10-fold risky). Noteworthily, viral infections work as risk markers already during infancy, a lot earlier than the sensitization to aeroallergens. The investigators also found retrospectively that early wheezers affected by rhinovirus responded to 3 day course of oral prednisolone (inexpensive and widely available treatment): recurrent wheezing decreased by 50% during following 12 months and the difference appeared to continue. VINKU 5V-study is currently investigating the clinical history, prevalence of asthma and airway hyperreactivity of these same children at school-age. The mechanism of rhinovirus associated risk or why they respond to prednisolone are largely unknown. However, the susceptibility to rhinovirus infections is associated with atopy and therefore it is possible these children may have impaired anti-inflammatory (Treg) responses and more likely to wheeze with any pro-inflammatory response (Th1 or Th2). Moreover, they may not effectively clear viruses, because they can not limit rhinovirus to nose and it spreads to lower airway