Safety, Tolerability, Immunogenicity and Immunological Mechanisms of TETRALITE, a Novel Seasonal Influenza Vaccine

Inclusion Criteria:

1. Written signed informed consent obtained before any study-related activities.

2. Aged 18 to 50 years inclusive, at the time of signing the ICF in the younger agecohorts (Cohort 1, Cohort 2 and Cohort 3) and aged 60 years or older, at the time ofsigning the ICF in the older age cohorts (Cohort 4, Cohort 5 and Cohort 6).

3. Participants who are considered to be in good general health as determined bymedical evaluation including medical history, physical examination (PE) andlaboratory tests within 21 days prior to enrollment.

4. Participants with a BMI within the range 18.5 to 35 kg/m2 inclusive at screening.

5. Women who are not pregnant or breastfeeding, and one of the following conditionsapplies

• Women of non-childbearing potential (WONCBP) as defined in Appendix 1. or

• WOCBP and using a highly effective contraceptive method (with a failure rate ofless than 1 % per year) as defined and described in Appendix 1 from at least 1month prior to study vaccination and for 3 months post-vaccination. Theinvestigator should evaluate the potential for contraceptive method failure (e.g. noncompliance, recently initiated) in relationship to study vaccination.The reliability of sexual abstinence needs to be evaluated in relation to theduration of the study and the preferred and usual lifestyle of the participant.The participant should commit her abstinence to at least 1 month prior to studyvaccination and for 3 months post-vaccination. If the participant will notmaintain abstinence and changes her status, the participant must first committo another highly effective method of contraception, which should be discussedwith the investigator prior to terminating sexual abstinence as contraceptivemethod (34).

6. WOCBP must have a negative serum pregnancy test at screening and a negative urinepregnancy test before vaccination at Day 1. Refer to Section 8.3.5 for PregnancyTesting. The investigator is responsible for review of medical history and menstrualhistory to decrease the risk for inclusion of a woman with an early undetectedpregnancy.

7. Participants who are willing and able to comply with the study procedures and are inthe view of the investigator capable of completing the study.

Exclusion Criteria:

Medical Conditions

1. History of previous laboratory confirmed influenza infection in the past 6 months,excluding laboratory confirmed COVID-19 infections, prior to the day of studyvaccination.

2. Positive (in the past, suspected or ongoing) for hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibody, and human immunodeficiency virus (HIV)antibody.

3. Past or current history of immune-mediated and/or autoimmune diseases as indicatedby the investigator, e.g. diabetes mellitus type I and thyroid disease.

4. Serious reactions to vaccines that preclude receipt of study vaccinations asdetermined by the investigator.

5. Clinical conditions representing a contraindication for IM administration, as judgedby the investigator, e.g. history of bleeding disorder (e.g. factor deficiency,coagulopathy, or platelet disorder requiring special precautions) or significantbruising or bleeding difficulties with IM administration or blood draws.

6. History of confirmed hypersensitivity, allergy and/or anaphylaxis to eggs (ovalbuminor chicken proteins), squalene-based adjuvants, or other components of the studyvaccine (neomycin, formaldehyde or octoxinol-9).

7. Current history of uncontrolled medical illness (unstable for the past 3 months) asjudged by investigator, e.g. hypertension, diabetes mellitus type 2.

8. Past or current history of any neurological disorder, e.g. Guillain-Barré syndromeand seizure disorder other than: 1) childhood febrile seizures, or 2) seizures thathave not required treatment within the last 3 years.

9. History of asplenia, functional asplenia or any condition resulting in the absenceor removal of the spleen.

10. Active malignancy or malignancy within the past 5 years, except basocellularcarcinoma (single lesion) that has been fully removed.

11. Asthma that is unstable or required emergent care, urgent care, hospitalization orintubation during the past 2 years or that is expected to require the use of oral orintravenous corticosteroids.

12. History of hereditary angioedema, acquired angioedema or idiopathic forms ofangioedema.

13. History of idiopathic urticaria within the past year.

14. Current or recent (< 2 years ago) heavy smoking (> 20 cigarettes per day). Ifcandidate stopped smoking > 2 years ago, the investigator will make an individualjudgement based on the total packs per year and the candidate's overall healthstatus. Drug - or alcohol abuse/addiction (including alcohol dependence), orpsychiatric condition (e.g. past or present psychoses; disorder requiring lithium;or within 5 years prior to administration of study vaccine, a history of suicideplan or attempt), which in the investigator's opinion could compromise theparticipant's safety and/or compliance with the protocol.

15. A rash, dermatological condition or tattoos that would, in the opinion of theinvestigator, interfere with injection local reaction rating. Prior/Concomitant Therapy

16. Prior receipt of an investigational or licensed seasonal or pandemic influenzavaccine in the 9 months before administration of study vaccine or planning toreceive the influenza vaccination during the study period.

17. Prior receipt of a live attenuated vaccine in the 28 days prior to administration ofstudy vaccine, or within 14 days for subunit or inactivated vaccines other thanseasonal or pandemic influenza vaccination, excluding COVID-19 vaccine.

18. Prior receipt of vaccination with TETRALITE + 0.5 mg LVA or TETRALITE + 2 mg LVA.

19. Prior receipt of COVID-19 vaccine in the 7 days before administration of studyvaccine, or planning to receive a COVID-19 vaccine during the first 14 daysfollowing study vaccination.

20. Planning to receive a vaccine during the first 28 days following the administrationof study vaccine, other than COVID-19 vaccine.

21. Currently participating in another clinical study, or planning to participate inanother study during the study period, or administration of any investigationaldrug, vaccine or medical device in the 4 weeks prior to study vaccination (with theexception of influenza vaccine, refer to exclusion criterium 16).

22. Prior receipt of blood, blood-derived products or immunoglobulins in the 6 monthsprior to administration of study vaccine, or planning to receipt such product duringthe study period.

23. Chronic administration (defined as 14 consecutive days in total) ofimmunosuppressants or other immune-modifying drugs during the period starting 90days prior to vaccination or planned administration during the study (excludingtopical, inhaled and intranasal preparations and intra-articular injections). Forcorticosteroids, this is prednisone >= 20 mg/day, or equivalent.

24. Current intake of more than 1 anticoagulant medication (coumarin derivatives, lowmolecular weight heparin, DOAC) or 1 anticoagulant medication in combination withantiaggregation medication.

25. Current anti-tuberculosis prophylaxis or therapy.

26. Elective surgery planned in the first 14 days following study vaccination. OtherExclusion Criteria

27. WOCBP who are pregnant, breast-feeding or planning to become pregnant during thestudy.

28. Participants with history of any medical conditions that, in opinion of theinvestigator, might interfere with the results of the study or pose additional riskto the participants due to participation in the study.