Alternative strategies for vaccine development against avian flu

Intense focus has been placed on investigation of vaccine strategies that provide cross-protection against H5N1. In April of 2007, an inactivated influenza A/Vietnam/ 1203/04 (H5N1) vaccine developed by Sanofi-Aventi was approved by the U.S. Food and Drug Administration, despite its suboptimal efficacy profile. Nonetheless, other approaches to vaccine development are being tested, including recombinant subunit, viral vectored and plasmid DNA (pDNA) vaccines. This chapter will focus on several alternative H5N1 vaccines and therapeutic antibody approaches not covered in previous reviews: linear DNA vaccines, protein-based flagellin conjugate vaccines, and an alphavirus based vaccine approach. In addition, we describe some of the animal models potentially useful for testing the efficacy of the vaccine candidates against avian influenza.