Influenza causes substantial mortality in high-risk groups despite targeted vaccination programmes. This paper considers whether it is worth vaccinating healthcare workers (HCWs) against influenza to protect high-risk patients in a series of systematic reviews and an economic evaluation. Eighteen studies are included. Vaccination was highly effective in HCWs, with minimal adverse effects. Two trials assessed patient mortality after vaccinating HCWs, both of which showed a reduction. Despite recommendations, less than 25% of HCW in Europe and the UK are vaccinated. Five studies looked at programmes to increase uptake; these produced increases of 5%-45%. Published economic evaluations did not include patient benefit; therefore, an economic evaluation using UK data was undertaken. In the base case, vaccination was cost saving (pounds 12/vaccinee). In the most pessimistic scenario it cost pounds 405/life-year gained. Effective implementation should be a priority.