It is spread by respiratory droplets. Influenza is usually self-limiting, but complications such as pneumonia and bronchitis can be serious threats to newborns, the elderly, and people with chronic diseases. Type B is more likely to occur sporadically. Because a number of different viral strains can cause the disease, immunity to one type does not prevent susceptibility to another. The antiviral drugs amantadine and rimantadine are effective against type A influenza, and zanamivir against types A and B. Treatment with antibiotics has greatly reduced fatalities from secondary infections.
Uncomplicated influenza requires only rest and treatment of symptoms.
Return to normal activity should be undertaken slowly, as relapses are easily precipitated.