If you’re thinking about having the influenza vaccine, the independent Cochrane Collaboration produced a meta analysis of the efficacy of various vaccines in 2010 which can be found at this link: http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD001269.pub4/full
In a nutshell they conclude that: “Inactivated influenza vaccines decrease the risk of symptoms of influenza and time off work, but their effects are minimal, especially if the vaccines and the circulating viruses are mismatched. There is no evidence that they affect complications or transmission.” I think you can make up your own mind about whether to have the flu vaccine or not. I am not even going to comment on how much this has costed the NHS.