A Study to Learn About a Modified RNA Vaccine Against Shingles in Healthy Adults

Substudy A

Inclusion Criteria:

1. Male or female participants 50 through 69 years of age (inclusive) at the time of
consent.

2. Healthy participants who are determined by clinical assessment, including medical
history and clinical judgment of the investigator, to be eligible for inclusion in the
study. Note: Known infection with HIV, HCV or HBV is an exclusion in Substudy A.

3. Participants who are willing and able to comply with all scheduled visits,
investigational plan, laboratory tests, lifestyle considerations, and other study
procedures.

4. Capable of giving signed informed consent, which includes compliance with the
requirements and restrictions listed in the ICD and in this protocol

Exclusion Criteria:

1. History of HZ (shingles).

2. History of Guillain-Barré syndrome.

3. Known infection with HIV, HCV, or HBV.

4. History of severe adverse reaction associated with a vaccine and/or severe allergic
reaction (eg, anaphylaxis) to any component of the study intervention(s).

5. Immunocompromised individuals with known or suspected immunodeficiency, as determined
by history and/or laboratory/physical examination.

6. Bleeding diathesis or condition associated with prolonged bleeding that would, in the
opinion of the investigator, contraindicate intramuscular injection.

7. Other medical or psychiatric condition including recent (within the past year) or
active suicidal ideation/behavior or laboratory abnormality that may increase the risk
of study participation or, in the investigator's judgment, make the participant
inappropriate for the study.

8. Women who are pregnant or breastfeeding.

9. Prior history of heart disease (eg, heart failure, recent coronary artery disease,
cardiomyopathies, pericarditis/myocarditis).

10. Previous vaccination with any varicella or HZ vaccine.

11. Individuals who receive treatment with immunosuppressive therapy, including cytotoxic
agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or
planned receipt throughout the study.

12. Receipt of blood/plasma products or immunoglobulin, from 60 days before study
intervention administration or planned receipt throughout the study.

13. Any participant who has received or plans to receive an RNA vaccine 28 days prior to
Vaccination 1.

14. Participation in other interventional studies within 28 days prior to study entry or
anticipated involvement through and including 6 months after the last dose of study
intervention. Participation in observational studies is permitted.

15. Any screening hematology and/or blood chemistry laboratory value that meets the
definition of a ≥ Grade 1 abnormality; or any abnormal bilirubin or troponin I value.

16. Screening 12-lead ECG that, as judged by the investigator, is consistent with probable
or possible myocarditis/pericarditis or demonstrates clinically relevant abnormalities
that may affect participant safety or interpretation of study results.

17. Participation or planned participation in strenuous or endurance exercise within 7
days before or after each study intervention administration.

18. Investigator site staff directly involved in the conduct of the study and their family
members, site staff otherwise supervised by the investigator, and sponsor and sponsor
delegate employees directly involved in the conduct of the study and their family
members.

SubStudy B:

Inclusion Criteria:

1. Male or female participants 50 through 69 years of age (inclusive) at the time of
consent.

2. Healthy participants who are determined by clinical assessment, including medical
history and clinical judgment of the investigator, to be eligible for inclusion in the
study.

3. Participants who are willing and able to comply with all scheduled visits,
investigational plan, laboratory tests, lifestyle considerations, and other study
procedures.

4. Capable of giving signed informed consent, which includes compliance with the
requirements and restrictions listed in the ICD and in this protocol.

Exclusion Criteria:

1. History of HZ (shingles).

2. History of Guillain-Barré syndrome.

3. History of severe adverse reaction associated with a vaccine and/or severe allergic
reaction (eg, anaphylaxis) to any component of the study intervention(s).

4. Immunocompromised individuals with known or suspected immunodeficiency, as determined
by history and/or laboratory/physical examination.

5. Bleeding diathesis or condition associated with prolonged bleeding that would, in the
opinion of the investigator, contraindicate intramuscular injection.

6. Other medical or psychiatric condition including recent (within the past year) or
active suicidal ideation/behavior or laboratory abnormality that may increase the risk
of study participation or, in the investigator's judgment, make the participant
inappropriate for the study.

7. Women who are pregnant or breastfeeding.

8. Prior history of heart disease (eg, heart failure, recent coronary artery disease,
cardiomyopathies, pericarditis, or myocarditis).

9. Previous vaccination with any varicella or HZ vaccine.

10. Individuals who receive treatment with immunosuppressive therapy, including cytotoxic
agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or
planned receipt throughout the study.

11. Receipt of blood/plasma products or immunoglobulin, from 60 days before study
intervention administration or planned receipt throughout the study.

12. Any participant who has received or plans to receive an RNA vaccine 28 days prior to
Vaccination 1.

13. Participation in other interventional studies within 28 days prior to study entry or
anticipated involvement through and including 6 months after the last dose of study
intervention is prohibited. Participation in observational studies is permitted.

14. Investigator site staff directly involved in the conduct of the study and their family
members, site staff otherwise supervised by the investigator, and sponsor and sponsor
delegate employees directly involved in the conduct of the study and their family
members.