Respiratory viral infection in exacerbations of COPD.

Background: Patients with COPD have frequent exacerbations. The role of respiratory viral infection is just emerging. We wished to determine prospectively the incidence of viral infection in exacerbated and stable COPD patients as well as smokers who do not have airways obstruction.

Methods: Stable and exacerbated COPD patients were recruited along with a group of patients who had smoked but who did not have any airways obstruction. Spirometry was performed and sputum specimens were tested for a range of 12 different respiratory viruses using PCR.

Results: One hundred and thirty-six patients with exacerbations of COPD, 68 stable COPD patients and 16 non-obstructed smokers were recruited. A respiratory virus was detected in 37% of exacerbations, 12% of stable COPD patients and 12% of non-obstructed smokers, p<0.0005. Rhinovirus was most frequently detected. The symptom of fever was associated with virus detection, p<0.05. Infection with more than one virus was only found in the exacerbated COPD patients.

Conclusion: Respiratory viral infection is associated with exacerbations of COPD. Rhinovirus was the most common infecting agent identified and in two cases human metapneumovirus was also detected. Dual infections were only seen amongst those patients admitted to hospital with acute exacerbations of COPD. Viruses were more commonly detected in those with more severe airways disease.