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 A: Group 11 to Group 14 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 (including use ofanticoagulant medications within 7 days prior to enrollment) that wouldcontraindicate IM injection or imply treatment or prophylaxis of known cardiac orvalvular disease. Note: The use of ≤325 mg of aspirin per day as prophylaxis is permitted, but the useof other platelet aggregation inhibitors, thrombin inhibitors, Factor Xa inhibitors,or warfarin derivatives from 7 days prior to enrollment through conclusion of studyparticipation is exclusionary.

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. This includes a history of alcohol or drug abuse asdetermined by the investigator.

8. Women who are pregnant or breastfeeding.

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

10. Participant with a history of autoimmune disease including, but not limited to,systemic or cutaneous lupus erythematosus, autoimmune arthritis/rheumatoidarthritis, multiple sclerosis, idiopathic thrombocytopenia purpura,glomerulonephritis, autoimmune thyroiditis, temporal arteritis, psoriasis, and/orinsulin dependent diabetes mellitus.

11. Previous vaccination with any varicella or HZ vaccine.

12. Individuals who receive treatment with immunosuppressive therapy, includingcytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmunedisease, or planned receipt throughout the study. If systemic corticosteroids havebeen administered short term (<14 days) for treatment of an acute illness,participants should not be enrolled in the study until corticosteroid therapy hasbeen discontinued for at least 28 days before study intervention administration.Inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes)corticosteroids are permitted.

13. Receipt of blood/plasma products or immunoglobulin, from 60 days before studyintervention administration or planned receipt throughout the study. Note: Nonimmunosuppressive monoclonal antibodies are permitted.

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

15. 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. Note: This criterion does not apply to participants who are participating in afollow-up period for another study involving an investigational drug or vaccine, ifreceipt of the last dose was at least 6 months prior to consenting for this studyand there is no further dosing anticipated from the previous study during theparticipant's participation in this study.

16. Any screening hematology and/or blood chemistry laboratory value that meets thedefinition of a ≥ Grade 1 abnormality; or any abnormal bilirubin or troponin Ivalue. Note: Any abnormal bilirubin or troponin I value above the ULN reference range isexclusionary. Participants with any stable Grade 1 abnormalities (according to thetoxicity grading scale), except bilirubin and troponin I, may be considered eligibleat the discretion of the investigator. (Note: A "stable" Grade 1 laboratoryabnormality is defined as a report of Grade 1 on an initial blood sample thatremains less than or equal to Grade 1 upon repeat testing on a second sample fromthe same participant during the screening period (prior to Visit 1). Please refer tothe laboratory normal ranges (provided separately in the central laboratory manual)for grading scales for abnormalities.

17. 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.Participants with a screening 12-lead ECG that shows an average QTcF interval >450msec, complete LBBB, signs of an acute or indeterminate-age myocardial infarction,ST-T interval changes suggestive of myocardial ischemia, second- or third-degree AVblock, or serious bradyarrhythmias or tachyarrhythmias should be excluded from studyparticipation.

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

19. 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 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.

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.

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.