Authors' conclusions: national policies for the vaccination of healthy children are based on very little reliable evidence. Influenza vaccines are efficacious in preventing cases of influenza in children older than two years of age, but little evidence is available for children younger than that. Further randomized clinical trials are needed to prove the efficacy and safety of influenza vaccines, especially regarding inactivated virus vaccines and children under two years of age.
Reviewers' conclusions: overall review of literature shows that universal influenza vaccination may have a favourable cost-benefit ratio. Nevertheless, there is scarce evidence about vaccine efficacy in children less than two years of age. So, given the difficulties to implement systematic influenza vaccination in Spain, at this time, it seems reasonable to maintain current recommendations, awaiting new efficacy and safety studies and the development of more effective vaccines.