In my mind that is the true benefit of the influenza vaccines: decreasing the morbidity and mortality of populations. The benefit for populations is derived through vaccinating individuals. That requires a bit of altruism on the part of those receiving the vaccine, as they may be getting vaccinated more for the benefit of others than for themselves. However, at least in the US, a premium is currently placed on being a self centered narcissist; indirectly helping others, even for MDs and RNs, is apparently not on the to do list.
Do flu vaccines work? It depends on what the meaning of is is. If you are simplistic and like binary answers, yes or no, then you can pick yes or pick no, and find studies to support your contention that the vaccine doesnt work.
If you realize that medicine is subtle and nuanced, and often the answers are filled with qualifiers and uncertainty, that the practice of medicine is messy, I think the answer is that the flu vaccine is of benefit. And that the more people who get the vaccine, the greater the benefit for everyone. You do not know how much it pains me to quote Donald Rumsfeld , but he was partly right when he said You go to war with the army you have, not the army you might want or wish to have at a later time.
It is true in medicine as well. My army is the vaccine and the data used to support it. You can conclude that neither the vaccine nor the data is perfect, and decide the vaccine is not useful.
Or you can look at the preponderance of data, with all the flaws, nuance, subtleties and qualifiers, and conclude the flu vaccine is of benefit. The vaccine decreases the probability of morbidity and mortality. It is a good thing.