Cause of flu deaths?

You ask an insightful question. Influenza certainly kills directly from viral pneumonia but also indirectly through a number of other means. One of these is damage to the mechanism (mucociliary escalator) that the body uses to clear inhaled bacteria from the airways. This leads to an increased risk of bacterial pneumonia due to pneumococcus and other microorganisms such as Staphylococcus aureus . Preventing influenza reduces the risk of these secondary infections.

Interestingly, influenza vaccination has been found to reduce death from all causes, including heart attack (myocardial infarction). Severe influenza — with fever, chills and dehydration — can certainly challenge an impaired cardiovascular system.

The bottom line is that people in the designated risk groups should get both vaccines — pneumococcal and yearly influenza — for maximum protection.