The randomized, double-blind, placebo-controlled efficacy study by Barrett et al. demonstrated the efficacy of cell culture-derived trivalent inactivated influenza vaccine (TIV), as manufactured by Baxter BioScience, in healthy adults 18-49 years of age. Efficacy and safety was comparable to that demonstrated by other recent randomized, placebo-controlled studies of cell culture-derived and egg-derived TIV in younger adults. The principal advantage of cell culture manufacturing of influenza vaccine relates to pandemic preparedness, although some advantages exist for seasonal vaccine production. The Barrett study confirmed a correlation between anti-hemagglutinin serum antibody and protection from influenza. However, further analysis of the correlation appears warranted in the Barrett study and in future studies to better describe antibody-induced and vaccine-induced protection from influenza illness.