You do your best to avoid sneezing, coughing people. But avoiding the surfaces that bear their germs is a tougher challenge. Virus-laden droplets can linger on everything from door knobs and light switches to phones, keyboards and countertops for up to 48 hours.

“Sneezing and coughing sends large droplets containing cold viruses out six feet or more,” says virus researcher Kelly A. Reynolds, MSPH, PhD, director of the Environment, Exposure Science and Risk Assessment Center at the University of Arizona. “The droplets linger in the air for a while, then settle on surfaces. A single droplet may contain thousands or even millions of viruses. It takes as little as one to ten viruses to become infected.”

Related: How to Control a Coughing Attack

“If the virus comes in contact with mucous membranes — your nose, mouth or eyes — you’ll likely catch a cold,” says Reynolds.

The average adult catches two to three colds per year; children average 8 to 12 colds. Following these steps could cut that number significantly.

How to steer clear of cold viruses

Wash your hands often. Lathering up and rinsing well five times a day reduced the number of upper respiratory infections among Navy recruits by 45 percent in a two-year study from the Naval Health Research Center in San Diego. The Centers for Disease Control and Prevention recommends wetting your hands, lathering up completely, scrubbing for 20 seconds (sing the “Happy Birthday” song twice) and then rinsing and drying. Use regular soap (antibacterial types don’t kill viruses). “If you can’t get to a sink, a hand sanitizer is a good alternative,” says Reynolds.

Don’t touch your face. In one recent study from the National Institutes of Health, researchers who observed 249 people in public places found that they touched their faces 3.6 times per hour. “You might rest your chin in your hand, flick hair out of your eyes, rub or scratch your nose or adjust your glasses and not even realize it,” says Reynolds. “Any time you touch your face, you could brush against your mouth, eyes or nose and transmit a cold virus that’s on your hands.”

Disinfect surfaces you touch frequently. In a new study, Reynolds and her colleagues found that a virus applied to the hand of an office worker spread to 50 percent of the surfaces in the office in just four hours. Coworkers unwittingly carried it into their own cubicles on their hands. The virus — which was harmless — ended up on light switches, cell phones, desk phones, computer keyboards, door knobs and drawer handles. But researchers also gave office workers disinfecting wipes and tissues and posted signs encouraging them to wash their hands.

“When people disinfected the surfaces in their own offices, they reduced their risk for catching a cold by 40 to 80 percent,” she says. “People think their personal space contains just their own germs and viruses, but in fact it also contains anything you’ve picked up on your hands elsewhere, too. Cleaning up your own surfaces can really help protect you.”

At home, Reynolds suggests, disinfect surfaces you and others touch often, such as kitchen and bathroom surfaces, light switches, phones, the TV remote control and your computer mouse.

Related: How Often Should You Wash Your Kitchen Towel?

Help your immune system stay strong

In addition to following Reynolds’ tips for avoid cold viruses, you can take steps to boost your immune system so it’s better able to fight off a cold.

Get regular exercise. In a recent University of Wisconsin-Madison study of 154 adults, those who exercised for 45 minutes a day had about 30 percent fewer colds than non-exercisers. And the colds they did get were shorter-lived and less severe. Exercise seems to help strengthen immunity — but don’t overdo it. Intense exercise may suppress immunity.

Meditate. The same University of Wisconsin-Madison study found that people who meditated for 45 minutes a day got about 33 percent fewer colds than non-meditators. And like the exercisers, the meditators who did get colds recovered faster and had milder symptoms. Why? Research suggests that mindfulness meditation can enhance immune function.

Try garlic, probiotics, or herbs. Countless studies have shown evidence in favor of, or against, countless natural remedies for colds and cold prevention. The bottom line: There is no magic bullet. But a few immune-boosters might be worth a try. Love garlic? A daily dose could cut your risk for catching a cold by two-thirds. That’s what happened in a study from the UK’s Garlic Centre when 146 women and men took a garlic capsule or placebo daily during cold season. The group that got real garlic caught 24 colds and the one that got fake garlic had 65 colds. Probiotics — beneficial bacteria found in yogurt, kefir and some other fermented foods — or a probiotic supplement may help your immune system battle cold viruses, too. In one study, people who took supplements of Lactobacillus gasseri, Bifidobacterium longum, and B. bifidum MF daily for three months still caught colds, but the colds were two days shorter than those of people who didn’t take the supplements. Certain herbs, such as andrographis, may also help. In one study, people who took two 100-milligram tablets daily for three months had 50 percent fewer colds than those who received a placebo.

Spritz with saline. Swedish researchers report that military recruits who used a saline nasal spray every day for 20 weeks reported 30 percent fewer colds than those who didn’t spritz. Dry nasal passages are more vulnerable to cold viruses.

Related: 5 Fast Ways to Unclog a Stuffy Nose

Sari Harrar is an award-winning health, medicine and science journalist whose work appears in Dr. Oz The Good Life magazine, Good Housekeeping, O--Oprah Magazine, Organic Gardening and other publications.