Rhinovirus-induced wheezing in infancy--the first sign of childhood asthma?

Abstract

Background: Although known as common causes of upper respiratory infections, rhinoviruses, enteroviruses, and corona-viruses are poorly studied as inducers of wheezing in infants, and their possible role in the development of childhood asthma has not been investigated.

Objective: The purposes of this study were to assess the occurrence of RV, enterovirus, and coronavirus infections in wheezing infants and to evaluate the association of these viral findings with early school-age asthma.

Methods: In 1999, outcome in relation to asthma was studied in 82 of 100 initially recruited children who had been hospitalized for wheezing in infancy during the period 1992-1993. In 2000, etiologic viral studies regarding the index episode of wheezing were supplemented by rhinovirus, enterovirus, and coronavirus detection by RT-PCR from frozen nasopharyngeal aspirates in 81 of the children for whom adequate samples were available. Of these children, 66 had participated in the follow-up in 1999.

Results: Rhinoviruses were identified in 27 (33%) of the 81 children, enteroviruses in 10 (12%), and coronaviruses in none. Rhinoviruses were present as single viral findings in 22 (81%) of the 27 rhinovirus-positive cases, and rhinovirus infections were associated with the presence of atopic dermatitis in infancy. Enteroviruses were commonly encountered in mixed infections and had no association with atopy. As single viral findings, rhinoviruses were associated with the development of asthma (P =.047; odds ratio, 4.14; 95% CI, 1.02-16.77 versus rhinovirus-negative cases [by logistic regression adjusted for age, sex, and atopic dermatitis on entry)].

Conclusion: Our results present rhinoviruses as important inducers of wheezing even in infancy. The association with atopy and subsequent asthma calls for reevaluation of the role of rhinoviruses in the development of asthma.

Fig. 1

Subgroups of the children in the present study. The term frozen samples refers to frozen NPA specimens obtained during the index episode of wheezing in infancy. PCR tests were performed to identify RVs, enteroviruses, and coronaviruses in these NPAs.

Fig. 2

RV and RSV findings in 81 infants hospitalized for wheezing, presented in 4 age groups. The viral findings have been classified into 3 categories: RSV-positive, RV-positive, and other/no viral findings. In 1 case (in the 1-to-5-months age group), both RSV and RV were identified; in the bar graph, that case is included in the RV-positive group.