Certain background infections may play etiologic role

Although the full clinical significance of a detected virus in a patient with community-acquired pneumonia remains unclear, recent findings suggest it likely plays a role in symptomatic illness.

Researchers, including Kathryn M. Edwards, MD, the Sarah H. Sell and Cornelius Vanderbilt Chair in Pediatrics at Vanderbilt University, conducted a prospective study in Nashville, Tennessee, and Salt Lake City, Utah, that was nested in the CDC’s Etiology of Pneumonia in the Community (EPIC) study. They sought to identify the prevalence of 13 viruses in the upper respiratory tracts of patients with community-acquired pneumonia (CAP) and asymptomatic controls using real-time reverse-transcriptase PCR.

The study, the largest in the United States to date on this topic, included 1,024 adult and pediatric patients with CAP and 759 asymptomatic controls, the researchers wrote.

Results showed that 127 children in the control group had more than one virus detected; the most common virus was human rhinovirus (hRV), which was detected in 17.3% of asymptomatic children.

There was at least one virus detected in 572 (68.8%) children with CAP. The most common viruses in this group were respiratory syncytial virus, or RSV (26.6%); hRV (21.9%); and human metapneumovirus, or hMPV (15.1%). The researchers said detection of these viruses was more common in children with CAP than in asymptomatic children.

There were only five (2.1%) viral detections in asymptomatic adults, whereas 47 (24.5%) adults with CAP had a viral detection, according to the researchers.

Overall, detections of influenza, RSV and hMPV were more common in patients with CAP of all ages than in asymptomatic patients (P < .01). Also, parainfluenza and coronaviruses were detected more often in patients with CAP. Rhinovirus was associated with CAP in adults, but not in children.

“Our data suggest that accounting for background circulation of respiratory viruses among asymptomatic persons is critical when investigating the causes of pneumonia, especially in children, who have more asymptomatic detections than adults,” the researchers wrote. – by Colleen Owens

Disclosure: Edwards reports receiving research funding and funding for Data Safety and Monitoring Board participation from Novartis. Please see the full study for a list of all other authors’ relevant financial disclosures.