When infants who are infected with rhinovirus develop wheezing, they are more likely to develop asthma by the age of 6 years, according to investigators who presented their findings here at the 2007 American Academy of Allergy, Asthma, and Immunology (AAAAI) annual meeting.
The findings presented were the most recent results of the Children Origins of ASThma (COAST) study, which is funded by National Institutes of Health.Infants who have lower respiratory involvement and particularly wheezing when infected with the common cold should be considered at risk for asthma, said principal investigator Kathleen A. Roberg, RN, MS, senior clinical nurse specialist, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States.The senior investigator was Robert F. Lemanske, professor of allergy and immunology, University of Wisconsin.”An infant who wheezes with a cold is 3 times more likely to develop asthma by the time he or she is 6 years old,” Roberg said in a press briefing on February 25th. However, she stressed that it is unknown whether the affected children had more severe strains of rhinovirus, or whether these children were already more vulnerable to wheezing when they were infected.Interestingly, no connection was found with respiratory viruses in infancy that are more severe than rhinovirus and more likely to cause wheezing, but less common, such as respiratory syncytial virus.The investigators assessed the nasal lavage specimens that had been collected during infancy from 287 COAST participants at study visits and when the children had symptomatic illnesses. Each participant had at least 1 parent with asthma.The investigators analysed for respiratory viruses the specimens using culture analysis and reverse transcription polymerase chain reaction (RT-PCR). They then classified the children’s respiratory tract symptoms by their severity and by the presence or absence of wheezing. The children were subsequently evaluated for asthma when they were 6 years old.Among the 41 participants who had wheezing while they were infected with a rhinovirus in infancy, 54% had a diagnosis of asthma by the age of 6 years. Among the 214 infants who did not wheeze when they were infected with rhinovirus, 23% were diagnosed with asthma at 6 years of age (P = .0002).Among those who had nonwheezing respiratory complications with rhinovirus, 29% had a recurrent wheeze when they were 3 years old, compared with 15% of those who did not (P = .01). However, the presence or absence of nonwheezing respiratory symptoms had no effect on whether children went on to develop asthma by the age of 6. Asthma occurred in 24% of those with nonwheezing respiratory symptoms and 22% of those without.Similarly, in the 47 who had an RSV wheezing illness during infancy, 38% had asthma by the age of 6, compared with 26% of those who did not, a difference that was not statistically significant.Among the 44 children who had wheezing in infancy due to viral infections that were neither rhinovirus nor RSV, 39% developed asthma compared with 26% who did not have such infections, a difference that was also not statistically significant.(Source: American Academy of Allergy, Asthma, and Immunology (AAAAI) Annual Meeting : University of Wisconsin : April 2007.)