The burden of influenza is substantial across all age groups. Vaccination against influenza has been shown to be safe and effective across all age groups. The benefits of vaccination may extend not only to the individual, but also to household contacts and even the community. Economic analyses generally suggest that vaccination is highly cost-effective and even cost saving for the elderly. Many studies also suggest similar findings for healthy younger adults. Data on the cost-effectiveness of vaccinating children are more limited, but several studies do suggest that vaccination of children might also be cost-effective. Universal immunization may represent an appropriate strategy for the prevention and control of influenza in settings where the vaccine supply, vaccine cost, and vaccine delivery infrastructure make such an approach feasible.