The main focus for not getting sick should be to get as healthy as possible. A healthy immune system can defend itself against most invaders. Maintain a healthy eating plan to give your immune system the support and nutrients it needs to do that job.

Ginger Tea with Lemon and Cinnamon: 
Ginger is excellent for colds and sore throats.Take it regularly and as soon as you feel the symptoms. I love to make a tea with a few slices of fresh ginger, a squeeze of lemon and a pinch of cinnamon to keep me healthy, especially through the winter. These ingredients also help to stimulate the digestive system making this tea helpful any time. If the ginger and lemon are too tart for you, try adding a tiny bit of splenda, maple syrup, brown rice syrup or another unrefined sweetener.

Garlic: 
Raw garlic is antiviral, antibacterial, antifungal, and an all-around health superstar. The best way to absorb the full power is to eat a clove raw every day. Add it to salads. homemade hummus or salsa.

Avoid Sugar: 
Sugar can knock your immune system out of commission because it drains your body of nutrients and artificially stimulates you. This is also true of alcohol and caffeine and if you have either on a regular basis it would be a good idea to cut them out. 
Anything healthy that boosts your immune system is negated if you eat lots of sugar or other unhealthy foods.

Tumeric: 
I love this herb. I cut a piece of the dry root, about the size of your little finger nail and lightly chew on it for as long as I can. Tumeric is a natural antiseptic and can help with a dry cough too, the one that keeps you up at night.