Sports fans, how many full on cases of true influenza do you think you've seen?
"Flu like symptoms" is what most people see or experience and that does NOT include nausea and vomiting. In fact, many people report they have the flu when it isn't in their area yet. Rule of thumb: when babies and senior citizens start dying from respiratory illness, it's flu.
You get the shot, you feel achey (hint: head it off with NSAIDS BEFORE injection), maybe a little feverish for a day or two...typical "flulike symptoms", but actually just your immune system kicking in.
"Real flu-like symptoms" would be rapid onset of bad headache, high fever, with strong URI symptoms followed by bronchitis of varying (often distressing) severity and sometimes pneumonia and death. It knocks you DOWN (or, as the books call it politely, "prostration").
If you haven't caught it and you are not hermetically sealed, thank those of us who had our shots, because we act as a "sponge" the advancing virus hits and can't travel further across. You contact a finite number of people a day, and every one immunized is one less "tree" of contacts spreading it into the susceptible community.
So which one is better: potentially fatal prostrating disease, or a couple days of coryza-like symptoms? What's the adult decision?
Sideshots: How many of you are current in your tetanus, typhoid, pertussis, hep B, hep A, and, if you work around animals a lot, rabies? Had your measles, mumps, rubella titres checked at least once?
Do you decon your rig after ALL respiratory cases?
And, about that "stomach flu"...if afebrile, usually food poisoning. If febrile, think about viruses we don't immunize against, and if you develop hepatic signs, hep A. Public health rules of thumb.