This is a Phase I/II, randomised, multicentre, partially double-blind (group 1, 2, 4 and 5), parallel-group study designed to primarily evaluate the safety, tolerability and immune response in older adults (age 50 to 75 years) following Immunose™ FLU vaccination at 5 sites in Sweden. A total of 300 subjects will be randomised to 1 of 7 treatment groups. The hypothesis is that Immunose™ FLU is safe and tolerable and will increase the influenza-specific mucosal immune response in older adults.

Inclusion Criteria:

1. Signed informed consent prior to any study related procedures.
2. Male or female 50 to75 years of age (both inclusive) at screening.
3. Subjects who the Investigator believes will comply with the requirements of the protocol.
4. Judged by the Investigator to have no serious illness based on medical history, physical examination, ECG, vital signs and blood and urine assessments at screening.
5. All females should have been post-menopausal for at least 12 months or use a highly effective contraceptive method to prevent pregnancy. Non-menopausal females have to use contraceptive methods with a failure rate of < 1% to prevent pregnancy (combined [oestrogen and progestogen containing] hormonal contraception associated with inhibition of ovulation [oral, intravaginal, transdermal], progestogen- only hormonal contraception associated with inhibition of ovulation [oral, injectable, implantable], intrauterine device [IUD], intrauterine hormone-releasing system [IUS], bilateral tubal occlusion, sexual abstinence). Any male partner should be willing to use condom or should be vasectomized.

Exclusion Criteria:

1. Diagnosis of laboratory-confirmed influenza in the 2017/2018 season.
2. Use of any investigational drug product within 3 months before screening or planned use during the study period, including the safety follow-up period.
3. Administration of an influenza vaccine during the 9 months before screening.
4. Previously received another vaccine within 28 days before administration of the study vaccine, or is scheduled to receive another vaccine during the study period, excluding the safety follow-up period.
5. Any contra-indication to intramuscular administration of the comparator influenza vaccine according to its SPC.
6. History of any anaphylactic reaction and/or serious allergic reaction following a vaccination, a proven hypersensitivity to any component of the study vaccine (e.g., to eggs or egg product as well as ovalbumin, chicken protein, chicken feathers, influenza viral protein, kanamycin, gentamycin, neomycin sulphate, formaldehyde and sodium deoxycholate).
7. Diagnosis of asthma with poor disease control as assessed by the Investigator.
8. Potent immunosuppressive therapy including cytostatics, antibodies, drugs acting on immunophilins, interferons and other drugs used to prevent rejection of organ transplants, within 6 months before screening.
9. Use of any parenteral or oral corticosteroids within 30 days prior to screening. Inhaled steroids are allowed.
10. Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination.
11. Any progressive or severe neurologic disorder, seizure disorder or Guillain-Barré syndrome.
12. Any history of Guillain-Barré syndrome.
13. Received blood, blood products and/or plasma derivatives or any administration of immunoglobulin preparation within the 3 months prior to Visit 2, or planned during the study.
14. Participation in blood donation within 3 months or plasma donation within 1 month prior to Visit 2.
15. History of substance or alcohol abuse within the past 2 years.
16. History or any illness/condition that, in the opinion of the Investigator, might interfere with the results of the study or pose additional risk to the subjects due to participation in the study.
17. Any positive result on screening for serum hepatitis B surface antigen, hepatitis C antibody or HIV.
18. Pregnant or lactating female or intent to become pregnant during the clinic phase and for 2 months after the last vaccination.
19. History of Bell's palsy.
20. Ongoing regular use of intranasal sprays including corticosteroids and decongestants.
21. Ongoing cough, sinusitis, allergic rhinitis, nasal polyps or obstruction, including septum deviation significant enough to prevent bilateral administration of study vaccine.
22. Known bleeding diathesis, or any condition that may be associated with a prolonged bleeding time.
23. Subjects that are prone to nosebleed.