Earlier this month, the Centers for Disease Control and Prevention released a report warning that flu season has come early—and it’s coming on strong. While in most years, incidence of flu picks up in January and peaks in February, the latest numbers from the last few weeks of November show that flu season has officially arrived. Get your tissues and hand sanitizers ready, troops, it’s going to be a long winter.Lab tests in 48 states have confirmed cases of influenza, and flulike illness in some areas has already topped last season’s totals. Google has a cool tool called Flu Trends where you can see where in the world people are searching most for flu-related information, an indication of who’s getting hit hardest. The U.S. is already at “High,” especially in the Southeast region. Not counting the infamous swine flu outbreak, we’re looking at what could be the worst flu season in nearly a decade.MORE: How to Make A Delicious Immunity-Boosting SmoothieThe flu is no fun (as if you needed us to tell you that!). Symptoms range from sniffles and chills to a high fever that keeps you home from work all week, or worse—flu lands 200,000 people in the hospital each year and kills more than 30 thousand in this country alone. There are antiviral drugs that can make you feel a little better and shorten the illness’s duration. But of course your best bet is to not get the flu in the first place! Fortunately there are several simple and smart ways to defend yourself this flu season. And none of them requires full body armor or hiding in a bunker until April.1. Get a flu shot.This one seems obvious, but it’s amazing how many people don’t get their flu shots. Only 37 percent of Americans got them last year, and it’s looking the same this year. There’s no guarantee that it will prevent your getting sick; the flu shot has been 60 to 70 percent effective in recent years. But it’s definitely worth a shot! Go to your doctor, a local clinic or one of many drug store chains that offer walk-in vaccination. It takes all of five minutes, kicks in after two weeks and will keep you flu-free through spring.MORE: The Many Hidden Benefits of Exercise2. Wash your hands … and your keyboard.And your phone. And doorknobs, faucets, the door to the fridge—any surface you use a lot and share with others. If the people around you are carrying the virus, they can spread it easily by touching or breathing on the stuff you use every day. And they might not even realize what they’re doing: You can start spreading the flu a full day before you even get that I’m-coming-down-with-something feeling.3. Keep moving.Regular exercise isn’t just great for the parts of your body you can see. It might also help keep your immune system in tip-top condition. There’s a clear connection between physical activity and immune function and researchers are trying to identify the specific effects. One early study found that women over 60 who kept active had more responsive immune reactions than their sedentary peers. Don’t let the cold weather keep you huddled on the sofa. Get your body in fighting shape—inside and out!4. Get plenty of sleep.If you do come into contact with the dreaded flu virus, it’s important that your body is ready to put up its dukes to fight it off. Your immune system needs all the energy it can get to successfully battle viral invaders. The hours you spend sleeping are when your body can focus on rest and replenishment. Fewer hours in bed means less energy and a weakened immune state.MORE: Sleep for Better Health5. Supplement your diet.There are several foods you can eat or supplements you can take to give your immune system some added power. Vitamin D3 helps your immune system. It’s hard to get enough from the winter sun, so consider taking supplements. You can also try chicken soup, large doses of vitamin C (500 mg every 4 hours), zinc lozenges, or anti-viral elderberry extract, all of which have been shown in studies to shorten the duration of colds or flus by 50 percent.