Egg-independent vaccine strategies for highly pathogenic H5N1 influenza viruses

Abstract

The emergence of a highly pathogenic H5N1 influenza virus in Hong Kong in 1997, and the subsequent appearance of other H5N1 strains and their spread to several countries in south-east Asia, Africa, the Middle East, and Europe has evoked fear of a global influenza pandemic. Vaccines offer the best hope to combat the threat of an influenza pandemic. However, the global demand for a pandemic vaccine cannot be fulfilled by the current egg-based vaccine manufacturing strategies, thus creating a need to explore alternative technologies for vaccine production and delivery. Several egg-independent vaccine approaches such as cell culture-derived whole virus or subvirion vaccines, recombinant protein-based vaccines, virus like particle (VLP) vaccines, DNA vaccines and viral vector-based vaccines are currently being investigated and appear promising both in preclinical and clinical studies. The present review will highlight the various egg-independent alternative vaccine approaches for pandemic influenza.