Authors' conclusions: live attenuated influenza vaccine (LAIV) in children under two years is more effective than placebo and as effective as inactivated influenza vaccine. The safety profile of LAIV is reasonable although evidence is scarce. LAIV may be considered as an option in this age group.
Reviewers' commentary: according to the available evidence, live attenuated virus influenza vaccines could be an alternative to inactivated vaccines, as they are at least as effective as these. Doubts about the safety of these vaccines (risk of episodes of wheezing), have limited the making of clinical trials, so that the available information is scarce, but not more scarce than that available about inactivated vaccines.