There are several factors that contribute to periodic outbreaks like this year. First is people's belief that getting the flu shot is a full-proof way to avoid catching the flu. In reality, the shot contains a "best guess" as to which flu strains will emerge as the dominant strains for the season. There are hundred/thousands of flu virus variations, and the flu shot covers only a handful. Some years, the scientists just guess wrong and an outbreak occurs - despite people getting the shot.
In my opinion, the real reason we see such outbreaks are due to a couple basic reasons - 1) people just don't take care of their health leaving them susceptible to the virus, 2) when people contract a virus rather than staying home to get well, they continue to go out in public which only serves to spread the virus.
The best way to keep yourself from getting the flu (or any similar illness, including the common cold) is to simply keep yourself hydrated (viruses cannot thrive in a "moist" environment), get proper rest/sleep, eat a good variety of fruits and vegetables (vitamins supplements alone are not enough), exercise to keep your lymphatic system flushed (only movement will release the toxins stored in your lymph nodes), and washing your hands before eating or touching your face (especially if you think you've come into contact with a virus).
If you've contracted a virus, do not go back to work or send your kid to school. That will just spread the disease to others making it worse. Keep them home, keep them as warm as possible (raising body temperature is one of the best ways to kill off a virus as long as the body temperature doesn't get too high), give them as much fluids (particularly water) as they can take. Only give them medication if they are having trouble breathing or are too achy to sleep - just the minimum amount.
One mistake people often make is when someone has a fever is to immediately take some medication to get rid of the fever. A fever is your body's natural mechanism for killing the virus and breaking a fever too soon only prolongs the illness. You should monitor the fever to make sure it doesn't raise too high (if it's up to 3 degrees above "normal"), just let it run its course. Taking juices or vitamin supplements during the illness really has no impact on the illness - that's just marketing. Plain water does the same trick - it's providing fluids to rehydrate the body and flush out the contaminates.
Just like how Mr. Miyagi in the Karate Kid said the best way to not get hit is "no be there", the best way to not suffer fighting the flu is to not let yourself get sick in the first place. If one drinks water, eats fruits/veggies, exercises, sleeps enough all the time - the chances of you getting sick will decrease rapidly - with or without the flu shot.