(Health.com) -- It's that time again: Everywhere you go, people are sniffling, sneezing, and coughing. Think you're next to get sick? Not necessarily.
"There are no guarantees, but you can seriously lower your odds of illness by taking simple precautions to avoid germs and keep your immune system humming," says Dr. Sandra Fryhofer, M.D., clinical associate professor of medicine at Emory University School of Medicine.
Use this checklist to stay healthy through cold-and-flu season and beyond.
Say yes to the flu shot
The big news this year is that the Centers for Disease Control and Prevention is now recommending that everyone 6 months and older get the influenza vaccine -- before, only those at highest risk of flu complications were urged to get it.
"There's a greater realization that we all interact with each other, so the best way to reduce the spread of flu is to vaccinate everyone," says Dr. Susan Rehm, M.D., medical director of the National Foundation for Infectious Diseases.
The ideal time to get vaccinated is before the onset of flu season (which is usually sometime in November or December), but it's never too late. You can opt for an injection or (if you're healthy and not pregnant) the FluMist nasal spray.
Get a new flu shot every year because you lose immunity over time and because the viruses targeted by the vaccine usually change from year to year. This year's formulation will also protect against H1N1 (a.k.a. swine flu), so there's no need for a separate shot.
Eat to beat illness
"Diet is the fuel that runs the complex human machine and all of its parts, including the immune system," says Dr. David Katz, M.D., director of the Yale Prevention Research Center.
Essential power players include high-quality protein, such as fish, lean meats, and beans, needed to help build white blood cells (the body's defenders); brightly colored fruits and veggies, which provide immune-boosting antioxidants; and omega-3 fatty acids (good sources include fatty fish, walnuts, and flaxseed) to keep the immune system balanced.
Exercise can keep you from getting sick by stimulating the immune cells that target cold infections, Fryhofer explains. A University of South Carolina study found that people who walked or did other moderate activity for 30 minutes most days averaged one cold per year, while less-active folks reported more than four colds per year.
Just don't overdo it: Heavy exertion -- like marathon training -- may increase your risk of catching seasonal bugs, perhaps because it can stress the body's systems, allowing viruses to gain a foothold.
Hydrate inside and out
Lower humidity and temperatures help the flu virus spread, which may explain why flu outbreaks peak in winter.
Humidity, on the other hand, kills the virus, so keep air at home warm and moist. Use a humidifier to maintain around 50 percent humidity and set room temperatures to at least 69 degrees F. If you're going to be in a superdry environment like an airplane cabin, protect yourself by using a saline nasal spray to moisten the membranes in your nose.
"When nasal passages are hydrated, the cilia, hair-like structures lining the nose, do a better job of keeping bacteria and viruses out," Fryhofer says.
Drink plenty of water, too: Your body needs H2O to execute many key immune functions, Katz says.
The good kind, that is. Probiotics are friendly microbes that may strengthen the immune system by crowding out bad germs that make us sick. A German study found that healthy men and women who took probiotics daily for three months shortened bouts of the common cold by almost two days and reported reduced severity of symptoms, such as headaches, coughing, and sneezing.
Aim for three servings a day of probiotic-rich foods -- yogurt with live bacteria, aged cheese, kefir, or other fermented foods (like sauerkraut or kimchi), says Gary Huffnagle, Ph.D., a professor of internal medicine at the University of Michigan Medical School and author of "The Probiotics Revolution." If you prefer a supplement, Huffnagle recommends choosing one with 3 billion to 5 billion CFU (colony-forming units).
Sleep on it
Logging less than seven hours sleep in the weeks before being exposed to a cold virus can make you three times more likely to develop a respiratory illness than if you got eight or more hours, according to a study published in 2009 in the Archives of Internal Medicine. That's because even minor sleep deprivation suppresses immune function.
Give germs the slip
Your biggest defense against lurking cold and flu bugs: old-fashioned hand-washing. Soap up long enough to sing "Happy Birthday" twice through (about 20 seconds); if you can't wash, use an alcohol-based hand sanitizer.
Be sure to scrub or sanitize after touching the germiest surfaces -- doorknobs, fridge handles, TV remotes, bathroom faucets, and money -- and after shaking hands. Keep your mitts off your face, to avoid giving germs a free ride into your eyes, nose, or mouth.
Germ-filled droplets can fly through the air, too, so if someone within 6 feet of you is coughing or sneezing, turn your head away for about 10 seconds while the air clears, Fryhofer advises, and (if you're in public, like in a café or on a bus or train) change seats as soon as you can.
And do your part to prevent the spread of germs: If you do get sick, sneeze into your sleeve, toss tissues immediately, and -- if possible -- stay home until you're better.
Copyright Health Magazine 2011