Weekly monitoring of children with asthma for infections and illness during common cold seasons.
BACKGROUND
Exacerbations of childhood asthma and rhinovirus infections both peak during the spring and fall, suggesting that viral infections are major contributors to seasonal asthma morbidity.


OBJECTIVE
We sought to evaluate rhinovirus infections during peak seasons in children with asthma and to analyze relationships between viral infection and illness severity.


METHODS
Fifty-eight children aged 6 to 8 years with asthma provided 5 consecutive weekly nasal lavage samples during September and April; symptoms, medication use, and peak flow were recorded. Rhinoviruses were identified by using multiplex PCR and partial sequencing of viral genomes.


RESULTS
Viruses were detected in 36% to 50% of the specimens, and 72% to 99% of the viruses were rhinoviruses. There were 52 different strains (including 16 human rhinovirus C) among the 169 rhinovirus isolates; no strains were found in more than 2 collection periods, and all but 2 children had a respiratory tract infection. Virus-positive weeks were associated with greater cold and asthma symptom severity (P < .0001 and P = .0002, respectively). Furthermore, virus-positive illnesses had increased duration and severity of cold and asthma symptoms and more frequent loss of asthma control (47% vs 22%, P = .008). Although allergen-sensitized versus nonsensitized children had the same number of viral infections, the former had 47% more symptomatic viral illnesses (1.19 vs 0.81 per month, P = .03).


CONCLUSIONS
Rhinovirus infections are nearly universal in children with asthma during common cold seasons, likely because of a plethora of new strains appearing each season. Illnesses associated with viruses have greater duration and severity. Finally, atopic asthmatic children experienced more frequent and severe virus-induced illnesses.
Olenec
Jaime P
JP
Department of Pediatrics, University of Wisconsin, Madison, WI 53792-4108, USA.
Kim
Woo Kyung
WK
Lee
Wai-Ming
WM
Vang
Fue
F
Pappas
Tressa E
TE
Salazar
Lisa E P
LE
Evans
Michael D
MD
Bork
Jack
J
Roberg
Kathleen
K
Lemanske
Robert F
RF
Gern
James E
JE
D001249:Asthma / Q000150:complications* / Q000503:physiopathology*; D002648:Child; D003139:Common Cold / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology; D005260:Female; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory; D016133:Polymerase Chain Reaction / Q000379:methods; D012141:Respiratory Tract Infections / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology; D012229:Rhinovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D012621:Seasons; D012720:Severity of Illness Index; D013997:Time Factors; D014777:Virus Diseases / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology
PLoS One. 2007 Oct 03;2(10):e966
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