The influenza pandemic of 1918 infected and affected almost everyone in the world.

An estimated 50 million people died as a result, making it three times more deadly than World War I, which claimed 16 million lives. As horrible as that was, an unchecked flu pandemic today could have even more devastating results.

A new study funded by the National Institutes of Health found that “obese adults with flu symptoms and laboratory-confirmed influenza shed influenza A virus for 42 percent longer than adults with flu who were not obese.” Meaning, they can infect others for much longer than normal-weight folks.

The study also notes that folks who have obesity don’t respond to the flu vaccine as positively as normal-weight folks and, if they get the flu, are far more likely to have complications and die. The Centers for Disease Control and Prevention recently reported that almost 40 percent of American adults are obese — the highest rates ever recorded for the U.S. So it has never been more important to get your flu vaccine, whatever your weight.

Also, practice infection control by staying home from work if you get the flu and washing your hands frequently.

Keep your immune system healthy, and increase the chance the flu vaccine will work by getting enough sleep and taking a multivitamin, especially in the week before your shot; reduce stress with meditation and exercise (10,000 steps daily); and eat healthfully by avoiding trans and saturated fats, added sugars and syrups, any grain that isn’t 100 percent whole, red meats and highly processed foods.

Mehmet Oz, M.D., is host of “The Dr. Oz Show,” and Mike Roizen, M.D., is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. Email questions to youdocsdaily@sharecare.com.