The purpose of this study is to evaluate the safety and immunogenicity of a sublingual administration of NSV0001 in healthy male volunteers.

NSV0001 is a quadrivalent influenza vaccine with the new adjuvant (ND002) administered by sublingual route.

This study will enroll healthy male adults. Participants will receive two doses of the vaccine, 4 weeks apart, and will stay in the investigational site for 2 consecutive days after each vaccination.

Participants will keep a patient diary to record the local and systemic reactions for one week after each vaccination. In addition, the safety monitoring will be extended through 6 months from the last vaccination to detect the potential immune mediated disorders (pIMD).

Inclusion Criteria:

1. Subject is 20 to 49 years of age on the date of informed consent
2. Individuals who are determined eligible healthy adult to participate clinical study from the results of medical history, medical examination and clinical estimation by principal investigator / sub-investigator.
3. Written informed consent was obtained from the subject. And the subject whom principal investigator/ sub-investigator judged about the following conditions; the subject will be able to follow study instructions, subject will be able to receive medical examination and tests prescribed in the protocol and subject will be able to inform indication, etc.
4. Individuals who will be able to receive telephone communication during clinical trial participations

Exclusion Criteria:

1. History of administration of seasonal influenza HA vaccine within 180 days
2. History of infection of influenza within 180 days
3. History of receiving live attenuated vaccine within 28 days or inactivated vaccine/ toxoid within 7 days
4. History of receiving any of following treatment such as medical drugs I. Within 28 days: 1. Interferon products, 2. Drugs affected to immune system (e.g., immunosuppressant), 3. Systemic or inhalant adrenocorticosteroid, 4. G-CSF and M-CSF II. Within 84 days: 1. HGG products, 2. Blood products, 3. blood transfusion (including blood component transfusion) III. Within 180 days: 1. massive dose therapy of HGG products (≥200 mg/kg)
5. History of previous causing of anaphylaxis by intake of foods or drugs (including vaccine)
6. History of previous finding to be suspected allergic reaction of oral cavity, pharynx or laryngeal mucosa
7. Individuals who have hypersensitivity against seasonal influenza HA vaccine or chicken egg, chicken meat and other chicken derived materials
8. Individuals who have experience of fever more than 39.0℃ or finding to be suspected allergic reaction e.g. generalized rash within two days after previous preventive treatment (seasonal influenza vaccine and other vaccines)
9. History of anamnestic convulsion (excluding anamnestic fever convulsion in childhood)
10. History of previously diagnosis of immunodeficiency, or individuals who have close relatives (within third degree) with congenital immunodeficiency syndrome
11. History of anamnestic Guillain-Barre syndrome or ADE (Acute Disseminated Encephalomyelitis)
12. Individuals who have poorly controlled cardiovascular, hematological, hepatic, renal, gastrointestinal, urological or endocrine metabolic diseases, and such diseases possibly affect to the participation of clinical study or study results
13. Individuals who have respiratory diseases e.g. interstitial pneumonia and bronchial asthma
14. Individuals who is associated with allergic rhinitis, and have a symptom
15. Individuals who have experienced whole blood donation of not less than 400 mL within 12 weeks, whole blood donation of not less than 200 mL within 4 weeks, or apheresis within 2 weeks
16. Individuals who have received other study medication within 4 months
17. Individuals who have inflammation, swelling or uncomfortable feeling, or mechanical problem in oral cavity, sublingual, tongue, pharynx or laryngeal mucosa, which disturbing sublingual administration or affecting absorption
18. Individuals who have not recovered from injury of laryngeal mucosa caused by treatment of dental extraction etc. (excluding treatment of carious teeth)
19. Individuals who is associated with disease with abnormal salivation (Sjogren's syndrome, well-defined dry mouth / xerostomia etc.)
20. Individuals who have positive reaction against any of STS (serological test for syphilis) (TP antibody, lipid antibodies), HBs antigen, HCV antibody, or HIV antigen/ antibody
21. History of anamnestic drug abuse (defined as illegal drug use) or alcoholism within one year before IMP dosing, or individuals who will not give up consuming excessive alcohol
22. Individuals who have clinically problematic abnormality in 12-lead electrocardiogram in the examination
23. Individuals who have been found abnormal value in clinical laboratory tests, which suggesting clinically problematic complications, or individuals who have been found abnormal value in the following test items: ALT and/ or AST that is more than 3 times of the upper limit of standard value.
24. In addition, individuals whom principal investigator/ sub-investigator judged inappropriate as the subject of such clinical trial