Viral community-acquired pneumonia in nonimmunocompromised adults.

INTRODUCTION Viral community-acquired pneumonia (CAP) has been poorly studied and clinically characterized. Using strict criteria for inclusion, we studied this type of infection in a large series of hospitalized adults with CAP. MATERIALS AND METHODS All nonimmunocompromised adult patients with a diagnosis of CAP having paired serology for respiratory viruses (RVs) [338 patients] were prospectively included in the study from 1996 to 2001 at our 1,000-bed university teaching hospital, and subsequently were followed up. We compared patients with pure viral (PV), mixed viral (RV + bacteria), and pneumococcal CAP. RVs (ie, influenza, parainfluenza, respiratory syncytial virus, and adenovirus) were diagnosed by means of paired serology. RESULTS Sixty-one of 338 patients (18%) with paired serology had an RV detected, and in 31 cases (9%) it was the only pathogen identified. Influenza was the most frequent virus detected (39 patients; 64%). Patients with chronic heart failure (CHF) had an increased risk of acquiring PV CAP (8 of 26 patients; 31%) when compared to a mixed viral/bacterial etiology (2 of 26 patients; 8%; p = 0.035) or CAP caused by Streptococcus pneumoniae (1 of 44 patients; 2%; p = 0.001). Multivariate analysis revealed that CHF (odds ratio [OR], 15.3; 95% confidence interval [CI], 1.4 to 163; p = 0.024) and the absence of expectoration (OR, 0.14; 95% CI, 0.04 to 0.6; p = 0.006) were associated with PV pneumonia compared to pneumococcal CAP. CONCLUSION RVs are frequent etiologies of CAP (single or in combination with bacteria). Patients with CHF have an increased risk of acquiring a viral CAP.