Is COPD caused by chronic viral infection? If so, in what percent of cases?

This, as well, is largely a consequence of chronic viral attack within vessels and cells lining the airways in the lung tissue, with a corresponding inflammatory response adding additional injury because it becomes so prolonged in a fruitless quest to eradicate the invading virus, but unsuccessfully. So what is routinely tolerated by the body for a short-term eradication of an invading microbe in the case of many bacterial illnesses, when it becomes chronic, the relentless immune attack becomes a liability over time, because the damage will build and it will be a kind of race against time whether repair mechanisms and the combination of immune attack and spread of the virus gains the upper hand. Over time, it is the patient who loses, one way or another, with at least loss of quality of life if not loss of longevity, from the compromised pulmonary function that worsens year by year in most cases.