Viruses Found Responsible for Burden of Hospitalizations from CAP

A new study conducted by the Centers for Disease Control and Prevention has revealed that the burden of community-acquired pneumonia that requires hospitalization is quite high, especially among older adults, and that respiratory viruses were more commonly the cause of pneumonia versus bacteria.

“These data suggest that improving the coverage and effectiveness of recommended influenza and pneumococcal vaccines and developing effective vaccines and treatments for HMPV, RSV, and parainfluenza virus infection could reduce the burden of pneumonia among adults,” study author Seema Jain, a medical epidemiologist at the CDC, and colleagues wrote in The New England Journal of Medicine.

The study included data on adults aged 18 and older taken from population-based surveillance of community-acquired pneumonia that required hospitalization in five hospitals in Chicago and Nashville. The researchers enrolled 2,488 adults, of whom 93% had radiographic evidence of pneumonia.

The median age of patients with pneumonia requiring hospitalization was 57 years.

“The estimated incidences of hospitalization for pneumonia among adults 50 to 64 years of age, 65 to 79 years of age, and 80 years of age or older were approximately 4, 9, and 25 times as high, respectively, as the incidence among adults 18 to 49 years of age,” the researchers wrote.

Disease specimens showed that only 38% of cases of pneumonia had a detectable pathogen. The researchers noted several factors that may have led to such a low detection rate, including the inability to obtain lower respiratory tract specimens, antibiotic use before specimen collection, or insensitive diagnostic tests for pathogens. Of those pathogens detected, 23% were one or more viruses, 11% were bacteria, and 3% were bacterial and viral.

Further analysis showed that rhinovirus was the most commonly occurring pathogen (9%), followed by influenza (6%) and Streptococcus pneumonia (5%).

Jain and colleagues also calculated the annual incidence of pneumonia requiring hospitalization and found that there were 24.8 cases per 10,000 adults (95% CI, 23.5-26.1). The overall incidence of pneumonia requiring hospitalization and that for each pathogen increased with increasing patient age.

“The incidences of influenza and of S. pneumoniae were almost 5 times as high among adults 65 years of age or older than among younger adults, and the incidence of human rhinovirus was almost 10 times as high among adults 65 years of age or older than among younger adults,” the researchers wrote.

Based on the results of this study, the researchers called for the “further development of new rapid diagnostic tests that can accurately identify and distinguish among potential pneumonia pathogens.”

References:

Jain S, Self WH, Wunderink RG, et al. Community acquired pneumonia requiring hospitalization among U.S. adults. N Engl J Med. 2015 Jul 14. Epub ahead of print.