What is the Role of Respiratory Viruses in Community Acquired Pneumonia; What is the Best Therapy for Influenza and Other Viral Causes of CAP?

Pavia, Andrew T

Respiratory viruses including influenza have long been appreciated as a cause of community acquired pneumonia (CAP), particularly among children, people with serious medical co-morbidities and military recruits. They are increasingly recognized as a cause of CAP among adults, particularly older adults. Polymerase chain reaction-based testing has allowed detection of newer agents (e.g. human metapneumovirus, coronavirus HKU1 and NL63) as well as improved the ability to detect “old” viral infections such as influenza virus and rhinovirus. When PCR is used, viruses have been detected in 45–75% of children and 15–54% of adults with CAP. Co-infection with viruses and bacteria is common and it remains challenging to determine which patients have only viral infection as the cause of CAP. Treatment for influenza with neuraminidase inhibitors should be started promptly for patients with CAP when influenza is suspected or documented, regardless of evidence of bacterial co-infection. Better ways to diagnose viral CAP and to integrate detection into management are urgently needed, as well as better treatment options for non-influenza respiratory viral infections.