Effectiveness of cell culture-based influenza vaccines compared with egg-based vaccines: What does the literature say?

Introduction. Influenza vaccination is an effective way of reducing the burden of seasonal influenza. Chicken egg embryos are the most common source of influenza vaccines, but cell culture production has emerged as an alternative that could be advantageous. This article reviews the available literature on the efficacy/effectiveness of cell culture-based influenza vaccines compared with egg-based vaccines. Methods. We conducted a review of the actual literature and analyzed those studies comparing the effectiveness of cell culture-based and egg-based vaccines in the last ten years. Results. Eight studies were analyzed; 1 was a clinical trial and 7 were retrospective cohort studies. The clinical trial found no significant differences in the efficacy of both vaccines with respect to placebo. The results of the observational studies were inconsistent and relative effectiveness varied among studies, even though most were performed during the same season, and in some cases, in the same region and using the same data records. Furthermore, in most studies, the comparisons between vaccines were not statistically significant. Conclusions. There is insufficient evidence that cell culture-based vaccines are superior to egg-based vaccines in terms of efficacy/effectiveness.