IStock Photo 9298971 © Robert Pears

The possibility of a widespread flu outbreak recurring has been part of the public consciousness since the influenza pandemic of 1918-1919 killed 20-50 million people around the world. More recently, threats of highly infectious “swine flu” and “avian flu” have attracted media attention and captured the public’s imagination. Although it does not cause global panic or have a catchy name, the plain ol’ seasonal flu, a crafty little virus whose genes are always gradually changing in order to fool human immune systems, is a real threat to public health every winter.

For most seasonal flu sufferers, a few days of fever, fatigue, muscle aches, and sore throat is indistinguishable (without laboratory testing) from a bad case of the common cold. But, unlike the common cold, seasonal influenza is responsible for more than 200,000 hospitalizations and 36,000 deaths every year in the United States. The odds a person will die from influenza in a year are 1 in 345,100 (slightly worse for women—1 in 307,400—than for men—1 in 395,900).

Being old, young, sick, or pregnant puts you at higher risk of suffering complications from the seasonal flu. The odds a person 85 years old or older will die from influenza in a year are 1 in 12,060and the odds that a child aged 1-4 years will die from influenza are 1 in 856,500. In contrast, the odds a person aged 25-34 will die of influenza in a year are 1 in 6,477,000. For adults and children who have other medical problems, including heart disease, asthma, chronic lung disease, cancer, kidney failure, and diabetes, influenza poses a significantly increased risk.

Although a few drugs exist to treat the flu, the best way to prevent influenza-related complications and death is to prevent infection in the first place. Simple things like staying home when you are sick, covering your mouth when you sneeze or cough, and washing your hands frequently will help slow the spread of the flu from person to person.

That said, the single-most effective way to prevent seasonal influenza is by getting a vaccination every year. The seasonal influenza vaccine, or “flu shot,” is created each year based on the three strains of the flu that are predicted to be the most widespread that season. Consequently, it does not prevent all cases of the flu, but (depending on how well the vaccine developers predict and match the strains) it is 50-90% effective. The CDC recommends that children 6 months to 19 years, adults over 50, pregnant women, people with certain chronic medical conditions, nursing home or other long-term care facility residents, healthcare workers, and all household contacts of anyone at high risk for the flu should get the vaccine. That’s more than ¾ of the U.S. population!

We are not meeting those goals. During the 2007-08 flu season, 1 in 3.77 people aged 6 months to 18 years were vaccinated against influenza. The elderly do a bit better—the odds a person 65 or older will have their yearly flu shot are 1 in 1.5 (67%). People not at heightened risk really seem to shy away from the shot: the odds a person 19-49 not in a high-risk category will be vaccinated during flu season are 1 in 5.75.

The viruses used to make the vaccine are killed, so it is impossible to get the flu from the flu shot. The odds the shot will give you a sore arm are pretty high, but it’s worth it. You might help save a life.