Community-acquired pneumonia (CAP) has traditionally focused little on viral causes, and few studies have done an extensive and appropriate evaluation for viral cause. The purpose of the present article is to review several issues of viral infection in CAP in light of recent studies that included exhaustive evaluation of viruses.
The introduction of better quality diagnostic tests, such as nucleic acid amplification techniques, have markedly improved our ability to detect multiple viral pathogens. With these diagnostic tools, a viral cause can be established in more than half of patients with CAP. Influenza A and respiratory syncytial virus are the most frequent causes of viral pneumonia followed by adenovirus, parainfluenza virus types 1, 2, and 3, and influenza. Although some clinical findings have been more frequent with viral infection, no clear-cut clinical signs have been shown to be predictive of specific cause. Of more interest is the association of mixed virus–bacteria infection with poorer severity scores found in some studies. The diagnostic approach with new techniques should be taken for a true estimation of viral infection in epidemiologic studies.
Unfortunately, there are no other licensed antivirals or vaccines against the large variety of clinically important respiratory viruses with the notable exception of influenza.
Given the high rate of viral infection in CAP and its probable association with poorer prognosis in mixed virus–bacteria infection, an extensive evaluation for virus in some populations seems appropriate. These findings can be useful for a more appropriate management of these patients.
aDepartment of Microbiology, Hospital Clínic i Provincial de Barcelona, Spain
bHospital Clínic de Barcelona, Institut Clínic del Tòrax, Servei de Pneumologia i Al·lergia Respiratoria, Universitat de Barcelona, IDIBAPS, CIBERES 06/06/0028, Barcelona, Spain
Correspondence to Antoni Torres, MD, Cap de Servei de Pneumologia i Al·lèrgia Respiratòria, Hospital Clínic de Barcelona, C/Villarroel 170, 08036 Barcelona, Spain Tel: +34 93 227 57 79; fax: +34 93 227 98 13; e-mail: firstname.lastname@example.org