It is perhaps worthwhile to review what is known about influenza.
1) The disease influenza, the gasping oppression, is a disease that has been plaguing humans for about 500 years. It is a predominantly respiratory infection, causing a protracted cough with fevers and myalgias. The term flu is used loosely to cover almost any febrile illness, and I remain uncertain as to what a stomach flu might be. I tend towards the picky side; flu is due to the influenza virus. There are many viri that can cause a flu like illness, but only the influenza virus causes the flu.
2) The flu is due to a virus, the influenza virus. There is influenza A and B and C. There are them what deny germs as a cause of disease, and I will admit that as an infectious disease doctor I have a vested interest in germs causing disease. After all, my job is me find bug, me kill bug, me go home.
3) Not every flu like illness is due to the influenza virus. In a given season the influenza virus may account for around 10-15% of flu like illness in the community, although during epidemics influenza can account for 60% of flu like illnesses.
4) Influenza kills. It kills directly, it kills by acute secondary infections, it kills by worsening underlying diseases like heart failure, it kills long term by increasing vascular events such as heart attacks and stroke. Influenza kills the young, the old, the obese and the pregnant. Deaths by influenza also depend on the virulence of the circulating strains. Some strains, such as H5N1 (the bird flu) or H3N2, are more likely to kill (60% for H5N1) than strains like H1N1 which was of moderate virulence. Influenza deaths, both direct and indirect, are difficult to measure and are at best an estimate. As an example somewhere between 151,700 to 575,400 people died worldwide from H1N1 the first year, with a mean of about 250,000.
ENTIRE ARTICLE HERE: Science-Based Medicine » Protect Yourself.