Someone just mentioned “herd immunity”. Being In LE for over 20, both myself and my fellow thin blue liners have come into contact with quit a number of mutants ,with various ailments.... like the flu. I never had a shot,nor have I ever got the flu. My family has never had it, considering the failed social engineering upstanding citizens I had a to deal with, is that what is considered “ herd immunity”?
You can definitely come in contact with someone who has the flu, and not contract it yourself. It's not the person who makes you sick, it's the virus. You have to contract the live virus itself into your body. Since influenza can be airborne, a contagious person can sneeze in your face and you will have a good chance of getting it, but not guaranteed.
If no one in your family has ever had influenza, then you need to call the Guinness Book and tell them. You are playing Russian roulette by not becoming vaccinated. Some strains of flu are not that bad. Some strains are exceptionally deadly to a person who is elderly or of diminished health.
As you get older, you should reconsider any phobias you may have towards vaccinations. Some of the viruses that cause pneumonia are especially aggressive and can kill you within 24 hours after the onset of symptoms. However, you can be vaccinated against these strains.