A Phase 2 Trial in Healthy Adult Participants of the Recombinant MVA-BN-WEV Vaccine

Inclusion Criteria:

1. Male and female participants ≥18 and ≤50 years of age at screening.

2. General good health, without clinically relevant medical illness, physical examfindings, or laboratory abnormalities, as determined by the investigator.

3. Prior to performance of any trial specific procedures, the participant has read,signed, and dated an informed consent form, having been advised of the risks andbenefits of the trial in a language understood by the participant, and has signedthe Health Insurance Portability and Accountability Act authorization form.

4. Body mass index (BMI) ≥18.5 and ≤35. a. BMI formula for pounds and inches: BMI = (body weight in pounds) × 703 / (bodyheight in inches)m2

5. Female participants should fulfil one of the following criteria:

6. At least 1 year post-menopausal (amenorrhea > 12 months) at screening.

7. Surgically sterile (bilateral oophorectomy, bilateral tubal ligation,hysterectomy)

8. Will use contraceptives as outlined in inclusion criterion 6 from screeninguntil 30 days after last vaccination.

9. Female participants of childbearing potential and male participants who are sexuallyactive with a female partner of childbearing potential must agree to the use of ahighly effective method of birth control from at least 30 days prior toadministration of the MVA-BN-WEV vaccine to until last vaccination. Note: medicallyacceptable methods of contraception that may be used by the participant and/orpartner include combined (estrogen and progestogen containing) hormonalcontraception associated with inhibition of ovulation (oral, intravaginal,transdermal), progestogen-only hormonal contraception associated with inhibition ofovulation (oral, injectable, implantable), intrauterine device (IUD), intrauterinehormone-releasing system (IUS), bilateral tubal occlusion, vasectomy or abstinence (abstinence only acceptable if refraining from heterosexual intercourse during theentire period of 30 days prior to administration of the MVA BN WEV vaccine until 30days after last vaccination).

10. Negative human immunodeficiency virus antibody test (anti-HIV), negative hepatitis Bsurface antigen (HBsAG) and negative antibody to hepatitis C virus.

Exclusion Criteria:

1. Pregnant or breast-feeding women.

2. Participant has an acute or chronic medical condition that, in the opinion of theinvestigator, would render the trial procedures unsafe or would interfere with theevaluation of the responses, including but not limited to, neurologic,cardiovascular, respiratory, hepatic, hematologic, rheumatologic, endocrine,gastrointestinal, renal, autoimmune, or immunosuppressive conditions.

3. History of or active autoimmune disease; persons with vitiligo or thyroid diseasetaking thyroid replacement are not excluded.

4. Known or suspected impairment of immunologic functions including, but not limitedto, clinically significant liver disease, diabetes mellitus type I, moderate tosevere kidney impairment. A known immunodeficiency syndrome.

5. Known or suspected previous alphavirus infections or previous vaccination (EEEV,VEEV, WEEV, Chikungunya).

6. Known or suspected previous smallpox vaccination, vaccination with a poxvirus-basedvaccine, or mpox infection.

7. History of malignancy other than squamous cell or basal cell skin cancer, unlessthere has been surgical excision at least 6 months prior to screening that isconsidered to have achieved cure. Participants with history of skin cancer must notbe vaccinated at the previous tumor site.

8. Clinically significant mental disorder not adequately controlled by medicaltreatment.

9. Active or recent history of chronic alcohol abuse and/or intravenous and/or nasaldrug abuse (within the period of 6 months before screening).

10. History of allergic disease or reactions likely to be exacerbated by any componentof the vaccine, eg, tris(hydroxymethyl)-amino methane, quail proteins.

11. History of anaphylaxis or severe allergic reaction to any vaccine.

12. Having received any vaccinations or planned vaccinations with a live vaccine within 30 days prior to first or after last trial vaccination.

13. Having received any vaccinations or planned vaccinations with a non-live orribonucleic acid (RNA-) based vaccine within 14 days prior to first or after eachtrial vaccination.

14. Recent blood donation (including platelets, plasma, and red blood cells) within 4weeks prior screening, or planned blood donations during active trial period (ie,until the end of the active trial visit).

15. Chronic systemic administration (defined as more than 14 days) of > 10 mg prednisone (or equivalent)/day or any other immune-modifying drugs during a period starting 3months prior to administration of the vaccine and ending at the end of the activetrial period Visit. The use of topical, inhaled, ophthalmic and nasalglucocorticoids is allowed.

16. Post organ transplant participants whether or not receiving chronicimmunosuppressive therapy.

17. Administration or planned administration of immunoglobulins and/or any bloodproducts during a period starting 3 months prior to administration of the vaccineand ending at the end of the active trial period Visit. Receipt of packed red bloodcells given for an emergency indication in an otherwise healthy person, and notrequired as ongoing treatment is not exclusionary (for example packed red bloodcells given in emergency during an elective surgery).

18. History of coronary heart disease, myocardial infarction, angina, congestive heartfailure, cardiomyopathy, stroke or transient ischemic attack, uncontrolled highblood pressure, significant arrhythmia with or without corrective/ablative surgery,or any other heart condition under the care of a doctor.

19. Use of any investigational or non-registered drug or vaccine other than the trialvaccine within 30 days preceding the administration of the trial vaccine, or plannedadministration of such a drug during the trial period until 12 months after the lastvaccination visit (stage 1) or 6 months after last vaccination (stage 2).

20. Employment with the investigator or CTS, with direct involvement in the proposedstudy or other studies under the direction of that investigator or CTS, orrelationship to the investigator or CTS employee.

21. Association with Bavarian Nordic as staff, contractors, agents, or business partnersor any financial interest in the outcome of the trial.

22. Federal employees and active-duty military personnel.