Viral respiratory infections are a common cause of severe disease, especially in infants,
people who are immunocompromised and in the elderly. Neutrophils, an important innate
immune cell, infiltrate the lungs rapidly after an inflammatory insult. The most well
characterized effector mechanisms by which neutrophils contribute to host defense are
largely extracellular and the involvement of neutrophils in protection from numerous
bacterial and fungal infections is well established. However, the role of neutrophils in
responses to viruses, which replicate intracellularly, has been less studied. It remains
unclear whether and, by which underlying immunological mechanisms, neutrophils
contribute to viral control or confer protection against an intracellular pathogen.
Furthermore, neutrophils need to be tightly regulated to avoid bystander damage to host
tissues. This is especially relevant in the lung where damage to delicate alveolar structures
can compromise gas exchange with life-threatening consequences. It is inherently less
clear how neutrophils can contribute to host immunity to viruses without causing
immunopathology and/or exacerbating disease severity. In this review we summarize and
discuss the current understanding of how neutrophils in the lung direct immune responses
to viruses, control viral replication and spread, and cause pathology during respiratory viral
infections.