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

Substudy A: Group 1 to Group 10

Inclusion Criteria:

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

2. Healthy participants who are determined by clinical assessment, including medicalhistory and clinical judgment of the investigator, to be eligible for inclusion inthe 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 studyprocedures.

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

Substudy A: Group 11 to Group 14

Inclusion Criteria:

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

2. Healthy participants who are determined by clinical assessment, including medicalhistory and clinical judgment of the investigator, to be eligible for inclusion inthe 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 studyprocedures.

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

5. Has a body mass index (BMI) between 18 and 35 (inclusive) kg/m2 at the screeningvisit.

Substudy A: Group 1 to Group 10

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 allergicreaction (eg, anaphylaxis) to any component of the study intervention(s).

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

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

7. Other medical or psychiatric condition including recent (within the past year) oractive suicidal ideation/behavior or laboratory abnormality that may increase therisk of study participation or, in the investigator's judgment, make the participantinappropriate 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, includingcytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmunedisease, or planned receipt throughout the study.

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

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

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

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

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

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

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

SubStudy B:

Inclusion Criteria:

1. Male or female participants 50 through 85 years of age (inclusive) at the time ofconsent.

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

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

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

5. Has a BMI between 18 and 35 (inclusive) kg/m2 at the screening visit.

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 allergicreaction (eg, anaphylaxis) to any component of the study intervention(s).

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

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

6. Other medical or psychiatric condition including recent (within the past year) oractive suicidal ideation/behavior or laboratory abnormality that may increase therisk of study participation or, in the investigator's judgment, make the participantinappropriate 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, includingcytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmunedisease, or planned receipt throughout the study.

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

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

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

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