To evaluate the protective effect 14 days after the live attenuated influenza vaccine; To evaluate the protective effect of vaccination with live attenuated influenza vaccine; To evaluate the safety of freeze-dried nasal spray live attenuated influenza vaccine; To evaluate the detoxification and genetic stability of lyophilized nasal spray vaccine.

To evaluate the protective effect of novel coronavirus after 14 days of inoculation with the live attenuated influenza vaccine.

Main end point:

Primary influenza protective effect endpoint Protective effect of 14 days on laboratory-confirmed influenza cases. Protective effect of 14 days after receiving lyophilized nasal spray live attenuated influenza vaccine on laboratory-confirmed serotype influenza cases.

Secondary endpoints:

Secondary point of secondary endpoint Protective effect of freeze-dried nasal spray live attenuated influenza vaccine 0 days later on laboratory-confirmed influenza cases.

Protective effect of freeze-dried nasal spray live attenuated influenza vaccine 14 days later on clinically diagnosed influenza cases.

Protective effect of live attenuated influenza-like vaccine 14 days against influenza-like cases.

safety Incidence of adverse events and serious adverse events within 0-30 days after immunization.

Study on detoxification Proproportion of vaccine attenuated proportion and vaccine attenuated content (titer) at different times after vaccination (days 3,7,15).

Exploration endpoint:

14 days after the freeze-dried nose vaccine, the vaccine was protective for the detection of COVID-19 cases.

Inclusion Criteria:

1. Local residents aged between 3 and 17;
2. People who signed the informed consent form and could actively cooperate with the study；
3. Axillary body temperature of 37.0℃.

Exclusion Criteria:

1. Subjects who meet the contraindications and precautions specified in the vaccine instructions:

   1. Those known to be allergic to any ingredients of this product, including eggs, excipients, gentamycin sulfate;
   2. Patients with acute disease, severe chronic disease, the acute onset of chronic disease and fever;
   3. Women in pregnancy;
   4. Patients with Leigh syndrome treated with aspirin or aspirin-containing drugs;
   5. Immunodeficient, immunocompromised, or under immunosuppressive therapy;
   6. Patients with uncontrolled epilepsy and other progressive neurological diseases, patients with a history of Guillain-Barre syndrome; And g. patients with rhinitis (with a clear diagnosis and in the onset of rhinitis).

2. Have received other clinical study drugs or were participating in other clinical trials within 1 month before entering the cohort.

3. Have received any influenza vaccine during this natural year before entering the study

4. Those who have been diagnosed with influenza in this natural year before entering the study.

5. Any condition that the investigator judged to affect the trial.