[Influenza vaccine].

The efficacy of seasonal influenza vaccines is not always high. However, this is not due to the vaccine itself, rather due to the viral frequent antigenic changes. Instead of the current chicken embryonated egg-based strategy for vaccine production, the use of the cell culture-based one may increase its productivity as well as efficacy. In addition, pre-pandemic H5N1 vaccines are now being stockpiled worldwide, although their total vaccine doses are limited due to their low productivity and immunogenicity. We need to recognize the importance of the vaccine-based prophylaxis against influenza considering recent prevalence of oseltamivir-resistant viruses such as H1N1 viruses.