Abstract: Vaccination can reduce illness and lessen severity of infection. This review focuses on how currently licensed influenza vaccines are generated, such as inactivated influenza vaccine, live attenuated influenza vaccine, and recombinated HA vaccine, and explain why the biology of new influenza virus poses vaccine challenges which include long production cycles, and emerge of novel influenza virus and immunosenescence in the elderly. Vaccine approaches on the horizon that address these challenges.

Key words: Key words: Influenza, Vaccines, Hemagglutinin, H1N1