One-site dose sparing intradermal influenza vaccination in elderly had been studied but resulted in unsatisfactory outcomes. The investigators evaluate the safety and immunogenicity of the two-site intradermal injection of influenza vaccine containing all 6 and 12 micrograms of hemagglutinin antigen per strain (with 4/10th and 8/10th of a regular 15 microgram HA/strain intramuscular vaccine respectively) in elderly over 60 years of age. An influenza vaccine administered intramuscularly at the standard dose is used as the reference vaccine.

The subjects would be randomly divided into three groups of 60 subjects each. Group1 receives a single intramuscular dose of 0.5 ml of trivalent influenza vaccine, containing at least 15 microgram of hemagglutinin antigen per strain, Group II receives two-site intradermal dose of 0.1 ml each, containing at least 3 microgram of hemagglutinin antigen per strain per site and group III receives two-site intradermal dose of 0.2 ml each, containing at least 6 microgram of hemagglutinin antigen per strain per site. Check for HA Antibody

Inclusion Criteria:

• healthy male or female volunteer aged at least 60 years old
• willing to participate in this study

Exclusion Criteria:

• previous influenza vaccination within 6 months
• systemic ypersensitivity to egg or chicken proteins or any of the vaccine components
• history of a life-threatening reaction to the study vaccine or a vaccine containing the same constituents.
• ongoing acute febrile illness (oral temperature, ≥37.5 c )
• congenital or acquired immunodeficiency
• treatment with immunosuppressive or other immune- modifying drugs or cancer therapy within previous 6 months
• long-term treatment with systemic corticosteroids
• receipt of blood or blood-derived products in the previous 3 months
• history of thrombocytopenia or a bleeding disorder contraindicating for intramuscular vaccination.