This study evaluates the safety of freeze-dried live attenuated influenza vaccine for intranasal administration in chinese adults aged 3 years and older.80 subjects will be divided into 2 groups, including 18 years and older and 3-17 years old. Subjects in each groups will randomly receive one dose of influenza vaccine or placebo in a 3:1 ratio.
Inclusion Criteria:
Exclusion Criteria: