Eligibility

Eligible Ages

Over 18 Years

Eligible Genders

All

Accepts Healthy Volunteers

Yes

Criteria

Participants are eligible to be included in the study only if all of the following
criteria apply:

1. Is at least 18 years old and has achieved legal age according to local regulations
in each participating country.

2. Must provide documented informed consent prior to any study procedures being
performed.

3. Can and will comply with the requirements of the protocol, in the opinion of the
investigator.

4. Is healthy or medically stable as determined by the investigator's judgment based on
medical history, vital sign measurements, and physical examination findings.
Participants with pre-existing stable disease, defined as disease not requiring
significant change in therapy or hospitalization for worsening disease during the 6
weeks before enrollment, can be included.

5. Prior receipt of an mRNA COVID-19 vaccine. This may be from a completed primary
vaccination series or booster dose(s) of an approved or authorized mRNA COVID-19
vaccine. The last vaccination must be an mRNA COVID-19 vaccination received at least
3 months prior to randomization.

6. If the participant is a woman of childbearing potential, the participant may be
enrolled in the study, if they:

- have practiced adequate contraception for 30 days prior to study intervention
administration; and

- have a negative pregnancy test result on the day of study intervention
administration; and

- have agreed to continue adequate contraception for 2 months after study
intervention administration.

Female participants of non-childbearing potential may be enrolled in the study.
Nonchildbearing potential is defined as current salpingectomy, hysterectomy, ovariectomy,
or postmenopausal.

Participants are excluded from the study if any of the following criteria apply:

1. Is pregnant or has a positive pregnancy test result at Visit 1.

2. Is breastfeeding or will (re)start breastfeeding from the study intervention
administration to 3 months after study intervention administration.

3. Has any medical disease or psychiatric condition that, in the opinion of the
investigator, precludes study participation because it would place the participant
at an unacceptable risk of injury, would render them unable to meet the requirements
of the protocol or may interfere with successful completion of the study.

4. Has any history of an immunosuppressive or immunodeficient condition resulting from
disease.

5. Has used immunosuppressants or other immune-modifying drugs for 14 consecutive days
or more within 3 months prior to the study intervention administration. Non-systemic
corticosteroids are allowed. If systemic corticosteroids have been administered
short term (<14 days) for treatment of an acute illness, participants should not be
enrolled into the study until corticosteroid therapy has been discontinued for at
least 28 days before study intervention administration.

6. Has an acute medical illness or acute febrile illness with oral temperature ≥38.0°C
or ≥100.4°F within 72 hours prior to study intervention administration.

7. Has participated in another study involving any investigational product, vaccine, or
device within 28 days before the study intervention administration and/or planned
participation through end of study (EoS).

8. Has participated in Part A of this study.

9. Has a history of hypersensitivity or severe allergic reaction including anaphylaxis,
generalized urticaria, angioedema, and other significant reactions to any previous
mRNA vaccine or any component of the study intervention(s).

10. Has received or plans to receive immunoglobulins or any blood or blood products
within 3 months before study intervention administration through EoS.

11. Has a bleeding disorder, or prior history of significant bleeding or bruising
following intramuscular injections.

12. Has a history of chronic alcohol consumption and/or drug abuse as deemed by the
investigator to render the potential participant unable/unlikely to provide accurate
safety reports or comply with study procedures.

13. Has a history of myocarditis, pericarditis, or idiopathic cardiomyopathy, or
presence of any medical condition that increases risk of myocarditis or
pericarditis, including cocaine abuse, cardiomyopathy, endomyocardial fibrosis,
hypereosinophilic syndrome, hypersensitivity myocarditis, eosinophilic
granulomatosis with polyangiitis and persistent myocardial infection.

14. Has received a live vaccine 30 days before the study intervention administration or
has a planned administration within 30 days after the study intervention
administration.

15. Has received a non-replicating vaccine 8 days before the study intervention
administration or has a planned administration within 14 days after the study
intervention administration.

16. Has a documented history of confirmed SARS-CoV-2 infection within 3 months before
study intervention administration.

17. Has had known close contact with anyone who had a confirmed SARS-CoV-2 infection
within 2 weeks before study intervention administration.

18. Is an employee or family member of the investigator or study site staff.