Emphysema is a form of chronic (long-term) lung disease, usually caused by smoking.

About 90 percent of all deaths from chronic obstructive lung disease are caused by smoking.

Those older than 65 and those with chronic lung and heart conditions should consider flu vaccines.

Most of the deaths occur among people older than 65 or those who have chronic lung and heart conditions.

Preterm birth that leads to lung damage (neonatal chronic lung disease).

Some children are at particularly high risk from the complications of flu, for example those who are immunosupressed or have chronic lung or heart disease.

Respiratory dysfunction (in the absence of cyanotic heart disease or known chronic lung disease)

Emphysema is a form of chronic (long-term) lung disease.

Susceptible people include the elderly and those with a history of smoking or underlying health problems like chronic lung or renal disease.

A small number of people may develop a chronic lung or widespread infection.