Vaccines in development against avian influenza.

Avian influenza has become a high priority item for all public health authorities. An influenza pandemic is believed to be imminent. The only questions are what will be the causative agent and when will it happen. Recently, most attention has been directed to human cases of avian influenza caused by an H5N1 avian influenza virus. An effective vaccine will be needed to substantially reduce the impact of an influenza pandemic. Despite the fact that the current influenza vaccine manufacturing technology is not adequate to support vaccine production in the event of a pandemic influenza outbreak, most of the ongoing clinical development is occurring with vaccines made in embryonated chicken eggs. It is clear that innovative production technology is required. This review provides an update on the status of avian vaccine development. In addition available manufacturing technologies are presented, some of which could be more suitable to adequately respond to an emergency situation where billions of doses of vaccines would be required within a very short period of time. The review is concluded with some proposed areas of focus for pandemic vaccine preparedness.