A H5N1 vaccine is an influenza vaccine intended to provide immunization to influenza A virus subtype H5N1. Vaccines have been formulated against several of the avian H5N1 influenza varieties. Vaccination of poultry against the H5N1 epizootic is widespread in certain countries. Some vaccines also exist for use in humans, and others are in testing, but none have been made available to civilian populations, nor produced in quantities sufficient to protect more than a tiny fraction of the Earths population in the event of an H5N1 pandemic. In January 2020, the U.S. Food and Drug Administration (FDA) approved Audenz, an adjuvanted influenza A (H5N1) monovalent vaccine. Audenz is a vaccine indicated for active immunization for the prevention of disease caused by the influenza A virus H5N1 subtype contained in the vaccine. Audenz is approved for use in persons six months of age and older at increased risk of exposure to the influenza A virus H5N1 subtype contained in the vaccine.Some older, egg-based H5N1 vaccines for humans that have been licensed are:

Sanofi Pasteurs vaccine approved by the United States in April 2007,
GlaxoSmithKlines vaccine Prepandrix approved by the European Union in May 2008, with reactive AS03 (containing squalene) adjuvant. and
CSL Limiteds vaccine Panvax approved by Australia in June 2008.Other licensed H5N1 vaccines include:

Adjupanrix, approved for medical use in the European Union in October 2009. Adjupanrix contains the flu strain A/VietNam/1194/2004 NIBRG 14 (H5N1). Foclivia, approved for medical use in the European Union in October 2009. Foclivia contains the flu strain A/Vietnam/1194/2004 (H5N1).
To achieve vaccine production targets millions of 11-day-old fertilized eggs must be available every day of production.In the near term, further expansion of these systems will provide additional capacity for the U.S.-based production of both seasonal and pandemic vaccines, however, the surge capacity that will be needed for a pandemic response cannot be met by egg-based vaccine production alone, as it is impractical to develop a system that depends on hundreds of millions of 11-day-old specialized eggs on a standby basis. In addition, because a pandemic could result from an avian influenza strain that is lethal to chickens, it is impossible to ensure that eggs will be available to produce vaccine when needed.In contrast, cell culture manufacturing technology can be applied to influenza vaccines as they are with most viral vaccines (e.g., polio vaccine, measles-mumps-rubella vaccine, chickenpox vaccine). In this system, viruses are grown in closed systems such as bioreactors containing large numbers of cells in growth media rather than eggs. The surge capacity afforded by cell-based technology is insensitive to seasons and can be adjusted to vaccine demand, as capacity can be increased or decreased by the number of bioreactors or the volume used within a bioreactor. In addition to supporting basic research on cell-based influenza vaccine development, HHS is currently supporting a number of vaccine manufacturers in the advanced development of cell-based influenza vaccines with the goal of developing U.S.-licensed cell-based influenza vaccines produced in the United States.