Safety and Immunogenicity of Live Attenuated Influenza H5N2

Inclusion Criteria: * Healthy * Age 18-49 years old * Having Thai ID card or equivalent * Are seronegative to the specific H5 influenza virus determined by antibody titer less than 1:40 by HAI test to the corresponding antigen. * Anti HIV - Negative * All hematology, biochemistry and urine analysis are within normal range or of no clinical significance (not more than 1.5 times of normal value) * Able to read and write and sign written informed consent. Exclusion Criteria: * Known history of egg allergy * Having had recently influenza infection confirmed as H5 * History of bronchial asthma * History of chronic lung diseases * History of chronic rhinitis * History of immunodeficiency state * History of immunosuppression * History of heavy smoking (more than 5 rolls per day) * History of alcoholic (pure drink 200 ml per day) * Acute infectious and noninfectious diseases (within 2 weeks) * Exacerbation of chronic diseases or cancer or HIV positives * Anamnestic leukocytosis, hepatitis B and C positives * The volunteers who have been taking immunoglobulin products or have had a blood transfusion during past three months before the beginning of the experiment * Participation in other research study or stop participant less than 1 month * Pregnancy or plan to become pregnant for 60 days after enrollment or breast feeding * Any concomitant medication with Aspirin * Poultry workers