ShinglesPhase 1/2NCT05703607
A Study to Learn About a Modified RNA Vaccine Against Shingles in Healthy Adults
A Phase 1/2 study testing Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for Injection, Candidate 1: PF-07915234: VZV modRNA Suspension for Injection and Candidate 2: PF-07921188: VZV modRNA Suspension for Injection in people with Shingles and Herpes Zoster Infection, run by Pfizer at 35 sites in United States.
Trial summary
The purpose of this clinical study is to learn about the safety, extent of the side effects (reaction to vaccine), and immune response (your immune system's reaction) of the study vaccine called Varicella Zoster Virus modRNA (VZV modRNA). We are seeking for healthy participants 50 through 85 years of age. Read more about this study
- Who is it for?
- Ages 50 to 85 yearsHealthy volunteers can take part
- Conditions the study is for
- Shingles, Herpes Zoster Infection, Human
- What is being tested?
- Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for Injection, Candidate 1: PF-07915234: VZV modRNA Suspension for Injection and Candidate 2: PF-07921188: VZV modRNA Suspension for Injection
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 484 participants
- Where
- 35 sitesUnited States
- Study dates
- 25 Jan 2023to 23 Sep 2025
- Phase
- Phase 1/2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 50 to 85 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Male or female participants 50 through 69 years of age (inclusive) at the time of consent.
- 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.
- Participants who are willing and able to comply with all scheduled visits, investigational plan, laboratory tests, lifestyle considerations, and other study procedures.
- Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the ICD and in this protocol
- Substudy A: Group 11 to Group 14
- Male or female participants 50 through 69 years of age (inclusive) at the time of consent.
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- 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.
- Participants who are willing and able to comply with all scheduled visits, investigational plan, laboratory tests, lifestyle considerations, and other study procedures.
- Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the ICD and in this protocol.
- Has a body mass index (BMI) between 18 and 35 (inclusive) kg/m2 at the screening visit.
- Substudy A: Group 1 to Group 10
- Male or female participants 50 through 85 years of age (inclusive) at the time of consent.
- 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.
- Participants who are willing and able to comply with all scheduled visits, investigational plan, laboratory tests, lifestyle considerations, and other study procedures.
- Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the ICD and in this protocol.
- Has a BMI between 18 and 35 (inclusive) kg/m2 at the screening visit.
Who cannot join
- History of HZ (shingles).
- History of Guillain-Barré syndrome.
- Known infection with HIV, HCV, or HBV.
- History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s).
- Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination.
- Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection.
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- 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.
- Women who are pregnant or breastfeeding.
- Prior history of heart disease (eg, heart failure, recent coronary artery disease, cardiomyopathies, pericarditis/myocarditis).
- Previous vaccination with any varicella or HZ vaccine.
- 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.
- Receipt of blood/plasma products or immunoglobulin, from 60 days before study intervention administration or planned receipt throughout the study.
- Any participant who has received or plans to receive an RNA vaccine 28 days prior to Vaccination 1.
- 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.
- 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.
- 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.
- Participation or planned participation in strenuous or endurance exercise within 7 days before or after each study intervention administration.
- 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:
- History of HZ (shingles).
- History of Guillain-Barré syndrome.
- History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s).
- Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination.
- Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection.
- 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.
- Women who are pregnant or breastfeeding.
- Prior history of heart disease (eg, heart failure, recent coronary artery disease, cardiomyopathies, pericarditis, or myocarditis).
- Previous vaccination with any varicella or HZ vaccine.
- 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.
- Receipt of blood/plasma products or immunoglobulin, from 60 days before study intervention administration or planned receipt throughout the study.
- Any participant who has received or plans to receive an RNA vaccine 28 days prior to Vaccination 1.
- 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.
- 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.
Trial locations and contacts
35 sites in 1 country.
35 sites in 1 country
United States35 sites
IMA Clinical Research
Albuquerque, New Mexico, 87109
CTI Clinical Research Center
Cincinnati, Ohio, 45212
Centennial Medical Group
Columbia, Maryland, 21045
Centricity Research Columbus Ohio Multispecialty
Columbus, Ohio, 43213
Columbus Cardiovascular Associates, Inc.
Columbus, Ohio, 43213
C.S. Mott Clinical Research Center (CRC)
Detroit, Michigan, 48201
Proactive Clinical Research,LLC
Fort Lauderdale, Florida, 33308
Tri-City Cardiology
Gilbert, Arizona, 85233
Henry Ford St. John Hospital
Grosse Pointe Woods, Michigan, 48236
East-West Medical Research Institute
Honolulu, Hawaii, 96814
University of Iowa
Iowa City, Iowa, 52242
Johnson County Clinical Trials
Lenexa, Kansas, 66219
West Valley Cardiology Services
Meridian, Idaho, 83642
Solaris Clinical Research
Meridian, Idaho, 83646
Aventiv Research Inc.
Mesa, Arizona, 85206
Acevedo Clinical Research Associates
Miami, Florida, 33142
NYU Langone Health
New York, New York, 10016
Tisch Hospital
New York, New York, 10016
Icahn School of Medicine at Mount Sinai
New York, New York, 10029
Velocity Clinical Research, Norfolk
Norfolk, Nebraska, 68701
Quality Clinical Research
Omaha, Nebraska, 68114
Stanford University Medical Center
Palo Alto, California, 94304
University of Nevada School of Medicine - Reno
Reno, Nevada, 89557
Rochester Clinical Research, LLC
Rochester, New York, 14609
Clinical Trials of Texas, LLC dba Flourish Research
San Antonio, Texas, 78229
Clinical Trials of Texas, LLC
San Antonio, Texas, 78229
IMA Clinical Research San Antonio
San Antonio, Texas, 78229
Associates in Cardiology, PA
Silver Spring, Maryland, 20910
South Jersey Infectious Disease
Somers Point, New Jersey, 08244
Dynamed Clinical Research, LP d/b/a DM Clinical Research
Tomball, Texas, 77375
Diablo Clinical Research, Inc.
Walnut Creek, California, 94598
GW Medical Faculty Associates
Washington D.C., District of Columbia, 20037
GW Vaccine Research Unit
Washington D.C., District of Columbia, 20037
Accellacare - Wilmington
Wilmington, North Carolina, 28401
Wilmington Health, PLLC (Cardiologist)
Wilmington, North Carolina, 28401
About this study
Official title: A PHASE 1/2 RANDOMIZED, OBSERVER-BLIND STUDY TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF A MODIFIED RNA VACCINE AGAINST VARICELLA ZOSTER VIRUS IN HEALTHY INDIVIDUALS
The purpose of this clinical study is to learn about the safety, extent of the side effects (reaction to vaccine), and immune response (your immune system's reaction) of the study vaccine called Varicella Zoster Virus modRNA (VZV modRNA). We are seeking for healthy participants 50 through 85 years of age.
This study will be conducted in 2 substudies: Substudy A (Phase 1) and Substudy B (Phase 2).
Read more
Substudy A:
This substudy is the Phase 1 portion of the study. In this substudy, participants will receive 1 of 3 VZV modRNA vaccine candidates (different construct, different dose levels and different formulation [frozen or freeze dry powder]) or the approved shingles vaccine intramuscularly.
Participants will be assigned in 1 of 10 groups in the study. Vaccination will be given either as a 2-dose series using one of two dosing schedules (either 2-months apart or 6-months apart), or (in one of the groups), as a single VZV modRNA vaccine at the first vaccination visit and saline at the second vaccination visit.
Participants will take part in this study for 8 to 12 months depending on the group they are assigned to. Some group(s) will continue into persistence-of-immunity (overtime assessment of effect of vaccine) portion of the study. Those participants assigned to these selected groups will be involved in the study for up to 5 years.
Substudy B:
This substudy is the Phase 2 portion of the study. In this part of the study, participants will receive either VZV modRNA vaccine at selected dose level/schedule/formulation or approved shingles vaccine. This selection was determined from data collected in Substudy A.
Participants will be involved in this study for up to 5 years.
- Conditions
- Shingles, Herpes Zoster Infection, Human
- Being tested
- Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for Injection, Candidate 1: PF-07915234: VZV modRNA Suspension for Injection, Candidate 2: PF-07921188: VZV modRNA Suspension for Injection, Candidate 3: PF-07921186: VZV modRNA Suspension for Injection, Shingrix
- Keywords
- Shingles, Vaccine, RNA vaccine, modRNA vaccine, Herpes zoster
- Medical subject headings
- Herpes Zoster, Chickenpox
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for InjectionBiological
Intramuscular injection
Candidate 1: PF-07915234: VZV modRNA Suspension for InjectionBiological
Intramuscular injection
Candidate 2: PF-07921188: VZV modRNA Suspension for InjectionBiological
Intramuscular injection
Candidate 3: PF-07921186: VZV modRNA Suspension for InjectionBiological
Intramuscular injection
ShingrixBiological
Intramuscular injection
Candidate 2: PF-07921188: VZV modRNA Powder for Suspension for InjectionBiological
Intramuscular injection
| Study group | Role | What they receive |
|---|---|---|
| SubStudy A (SSA): Group 1 | Experimental | Candidate 1, Dose Level 1, lyophilized, 0, 2 months schedule Receives: Biological: Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for Injection |
| SSA: Group 2 | Experimental | Candidate 1, Dose Level 2, lyophilized, 0, 2 months schedule Receives: Biological: Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for Injection |
| SSA: Group 3 | Experimental | Candidate 1, Dose Level 3, lyophilized, 0, 2 months schedule Receives: Biological: Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for Injection |
| SSA: Group 4 | Experimental | Candidate 1, Dose Level 2, frozen, 0, 2 months schedule Receives: Biological: Candidate 1: PF-07915234: VZV modRNA Suspension for Injection |
| SSA: Group 5 | Experimental | Candidate 1, Dose Level 2, Frozen, 0, 6 months schedule Receives: Biological: Candidate 1: PF-07915234: VZV modRNA Suspension for Injection |
| SSA: Group 6 | Experimental | Candidate 2, frozen, 0, 2 months schedule Receives: Biological: Candidate 2: PF-07921188: VZV modRNA Suspension for Injection |
| SSA: Group 7 | Experimental | Candidate 3, Frozen, 0, 2 months schedule Receives: Biological: Candidate 3: PF-07921186: VZV modRNA Suspension for Injection |
| SSA: Group 8 | Active comparator | Shingrix, 0, 2 months schedule Receives: Biological: Shingrix |
| SSA: Group 9 | Active comparator | Shingrix, 0, 6 months schedule Receives: Biological: Shingrix |
| SSA: Group 10 | Experimental | Candidate 1, Dose level 4, lyophilized, 0, 6 months schedule (saline at month 6) Receives: Biological: Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for Injection |
| Substudy B (SSB): Group 1 | Experimental | Candidate 2, Dose level 3, lyophilized, 0, 2 months schedule Receives: Biological: Candidate 2: PF-07921188: VZV modRNA Powder for Suspension for Injection |
| SSB: Group 2 | Experimental | Candidate 2, Dose level 4, lyophilized, 0, 2 months schedule Receives: Biological: Candidate 2: PF-07921188: VZV modRNA Powder for Suspension for Injection |
| SSB: Group 3 | Experimental | Candidate 2, Dose level 4, lyophilized, 0, 2 months schedule (saline at month 2) Receives: Biological: Candidate 2: PF-07921188: VZV modRNA Powder for Suspension for Injection |
| SSB: Group 4 | Active comparator | Shingrix, 0, 2 months schedule Receives: Biological: Shingrix |
What is being measured
The primary outcome is the main question the study is designed to answer.
SSA: Percentage of participants reporting local reactions
Pain at the injection site, redness, and swelling as self-reported in electronic diaries.
Measured: For 7 days after Vaccination 1 and Vaccination 2
SSA: Percentage of participants reporting systemic events
Fever, fatigue, headache, chills, vomiting, diarrhea, new or worsened muscle pain, and new or worsened joint pain, as self-reported in electronic diaries
Measured: For 7 days after Vaccination 1 and Vaccination 2
SSA: Percentage of participants reporting adverse events
As elicited by investigational site staff
Measured: From Vaccination 1 to 4 weeks after last vaccination
SSA: Percentage of participants reporting serious adverse events
As elicited by investigational site staff
Measured: From Vaccination 1 to 6 months after the last study vaccination
SSA: Percentage of participants reporting medically attended adverse event
As elicited by investigational site staff
Measured: From Vaccination 1 to 6 months after the last study vaccination
SSA: Percentage of participants with abnormal hematology and chemistry laboratory assessments
As measured at the central laboratory
Measured: 3 days and 1 week after each vaccination
SSA: Percentage of participants with new electrocardiogram (ECG) abnormalities
ECG abnormalities consistent with probable or possible myocarditis or pericarditis, as judged by a cardiologist
Measured: 3 days and 1 week after each vaccination
SSA: Percentage of participants with abnormal troponin I laboratory values
as measured at the central laboratory
Measured: 3 days and 1 week after each vaccination
SSB: Percentage of participants reporting local reactions
Pain at the injection site, redness, and swelling as self-reported in electronic diaries.
Measured: For 7 days after Vaccination 1 and Vaccination 2
SSB: Percentage of participants reporting systemic events
Fever, fatigue, headache, chills, vomiting, diarrhea, muscle pain, and joint pain, as self-reported in electronic diaries
Measured: For 7 days after Vaccination 1 and Vaccination 2
SSB: Percentage of participants reporting adverse events
As elicited by investigational site staff
Measured: From Vaccination 1 to 4 weeks after last vaccination
SSB: Percentage of participants reporting serious adverse events
As elicited by investigational site staff
Measured: From Vaccination 1 to 6 months after the last study vaccination
SSB: Percentage of participants reporting medically attended adverse events
As elicited by investigational site staff
Measured: From Vaccination 1 to 6 months after the last study vaccination
Secondary outcomes (6)
SSA: Geometric mean concentrations (GMCs) of glycoprotein E antibodies in proportion of evaluable immunogenicity participant
As measured at the central laboratory
Measured: At baseline (before vaccination 1), at 1- and 4-weeks after each vaccination and 6-months after last vaccination
SSA: Geometric mean fold rise (GMFR) from before vaccination to each subsequent timepoint in evaluable immunogenicity participants
As measured at the central laboratory
Measured: At baseline (before vaccination 1), at 1- and 4-weeks after each vaccination and 6-months after last vaccination
SSA: Proportion of evaluable immunogenicity participants with vaccine response in glycoprotein E antibodies from baseline to each subsequent timepoint
As measured at the central laboratory
Measured: At baseline (before vaccination 1), at 1- and 4-weeks after each vaccination and 6-months after last vaccination
SSB: Geometric mean concentrations (GMCs) of glycoprotein E antibodies in proportion of evaluable immunogenicity participant
As measured at the central laboratory
Measured: At baseline (before vaccination 1), at 4-weeks after each vaccination and 6-months after last vaccination
SSB: Geometric mean fold rise (GMFR) from before vaccination to each subsequent timepoint in evaluable immunogenicity participants
As measured at the central laboratory
Measured: At baseline (before vaccination 1), at 4-weeks after each vaccination and 6-months after last vaccination
SSB: Proportion of evaluable immunogenicity participants with vaccine response in glycoprotein E antibodies from baseline to each subsequent timepoint
As measured at the central laboratory
Measured: At baseline (before vaccination 1), at 4-weeks after each vaccination and 6-months after last vaccination
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Jan 2023
- Study start25 Jan 2023
- Primary completion23 Sep 2025
- Study completion23 Sep 2025
Why it stopped: Strategic decision made by the company
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ShinglesStudies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1/2
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 484 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- BioNTech SE
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05703607
- Sponsor's protocol ID
- C5031001
- Other IDs
- NCT05703607
- Status last verified
- Apr 2026
- First submitted
- 19 Jan 2023
- Last updated
- 4 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.
Study at a glance
From the registry record, last updated by the sponsor on 4 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A PHASE 1/2 RANDOMIZED, OBSERVER-BLIND STUDY TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF A MODIFIED RNA VACCINE AGAINST VARICELLA ZOSTER VIRUS IN HEALTHY INDIVIDUALS
- ClinicalTrials.gov ID
- NCT05703607
- Acronym / sponsor ID
- C5031001
- Conditions
- Shingles, Herpes Zoster Infection, Human
- Keywords
- Shingles, Vaccine, RNA vaccine, modRNA vaccine, Herpes zoster
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Strategic decision made by the company
- Enrolment
- 484 participants (actual)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Collaborators
- BioNTech SE
- Study start
- 25 Jan 2023 (actual)
- Primary completion
- 23 Sep 2025 (actual)
- Study completion
- 23 Sep 2025 (actual)
- First posted
- 30 Jan 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this clinical study is to learn about the safety, extent of the side effects (reaction to vaccine), and immune response (your immune system's reaction) of the study vaccine called Varicella Zoster Virus modRNA (VZV modRNA). We are seeking for healthy participants 50 through 85 years of age.
This study will be conducted in 2 substudies: Substudy A (Phase 1) and Substudy B (Phase 2).
Substudy A:
This substudy is the Phase 1 portion of the study. In this substudy, participants will receive 1 of 3 VZV modRNA vaccine candidates (different construct, different dose levels and different formulation [frozen or freeze dry powder]) or the approved shingles vaccine intramuscularly.
Participants will be assigned in 1 of 10 groups in the study. Vaccination will be given either as a 2-dose series using one of two dosing schedules (either 2-months apart or 6-months apart), or (in one of the groups), as a single VZV modRNA vaccine at the first vaccination visit and saline at the second vaccination visit.
Participants will take part in this study for 8 to 12 months depending on the group they are assigned to. Some group(s) will continue into persistence-of-immunity (overtime assessment of effect of vaccine) portion of the study. Those participants assigned to these selected groups will be involved in the study for up to 5 years.
Substudy B:
This substudy is the Phase 2 portion of the study. In this part of the study, participants will receive either VZV modRNA vaccine at selected dose level/schedule/formulation or approved shingles vaccine. This selection was determined from data collected in Substudy A.
Participants will be involved in this study for up to 5 years.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 14
| Arm | Type | Receives |
|---|---|---|
| SubStudy A (SSA): Group 1 | Experimental | Biological: Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for InjectionCandidate 1, Dose Level 1, lyophilized, 0, 2 months schedule |
| SSA: Group 2 | Experimental | Biological: Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for InjectionCandidate 1, Dose Level 2, lyophilized, 0, 2 months schedule |
| SSA: Group 3 | Experimental | Biological: Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for InjectionCandidate 1, Dose Level 3, lyophilized, 0, 2 months schedule |
| SSA: Group 4 | Experimental | Biological: Candidate 1: PF-07915234: VZV modRNA Suspension for InjectionCandidate 1, Dose Level 2, frozen, 0, 2 months schedule |
| SSA: Group 5 | Experimental | Biological: Candidate 1: PF-07915234: VZV modRNA Suspension for InjectionCandidate 1, Dose Level 2, Frozen, 0, 6 months schedule |
| SSA: Group 6 | Experimental | Biological: Candidate 2: PF-07921188: VZV modRNA Suspension for InjectionCandidate 2, frozen, 0, 2 months schedule |
| SSA: Group 7 | Experimental | Biological: Candidate 3: PF-07921186: VZV modRNA Suspension for InjectionCandidate 3, Frozen, 0, 2 months schedule |
| SSA: Group 8 | Active comparator | Biological: ShingrixShingrix, 0, 2 months schedule |
| SSA: Group 9 | Active comparator | Biological: ShingrixShingrix, 0, 6 months schedule |
| SSA: Group 10 | Experimental | Biological: Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for InjectionCandidate 1, Dose level 4, lyophilized, 0, 6 months schedule (saline at month 6) |
| Substudy B (SSB): Group 1 | Experimental | Biological: Candidate 2: PF-07921188: VZV modRNA Powder for Suspension for InjectionCandidate 2, Dose level 3, lyophilized, 0, 2 months schedule |
| SSB: Group 2 | Experimental | Biological: Candidate 2: PF-07921188: VZV modRNA Powder for Suspension for InjectionCandidate 2, Dose level 4, lyophilized, 0, 2 months schedule |
| SSB: Group 3 | Experimental | Biological: Candidate 2: PF-07921188: VZV modRNA Powder for Suspension for InjectionCandidate 2, Dose level 4, lyophilized, 0, 2 months schedule (saline at month 2) |
| SSB: Group 4 | Active comparator | Biological: ShingrixShingrix, 0, 2 months schedule |
Who may qualify
- Ages
- 50 to 85 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (16 listed)
- Male or female participants 50 through 69 years of age (inclusive) at the time of consent.
- 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.
- Participants who are willing and able to comply with all scheduled visits, investigational plan, laboratory tests, lifestyle considerations, and other study procedures.
- Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the ICD and in this protocol
- Substudy A: Group 11 to Group 14
Key exclusion criteria (33 listed)
- History of HZ (shingles).
- History of Guillain-Barré syndrome.
- Known infection with HIV, HCV, or HBV.
- History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s).
- Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for InjectionIntramuscular injection | Biological | SSA: Group 10, SSA: Group 2, SSA: Group 3, SubStudy A (SSA): Group 1 |
| Candidate 1: PF-07915234: VZV modRNA Suspension for InjectionIntramuscular injection | Biological | SSA: Group 4, SSA: Group 5 |
| Candidate 2: PF-07921188: VZV modRNA Suspension for InjectionIntramuscular injection | Biological | SSA: Group 6 |
| Candidate 3: PF-07921186: VZV modRNA Suspension for InjectionIntramuscular injection | Biological | SSA: Group 7 |
| ShingrixIntramuscular injection | Biological | SSA: Group 8, SSA: Group 9, SSB: Group 4 |
| Candidate 2: PF-07921188: VZV modRNA Powder for Suspension for InjectionIntramuscular injection | Biological | SSB: Group 2, SSB: Group 3, Substudy B (SSB): Group 1 |
Primary outcome
SSA: Percentage of participants reporting local reactions
Time frame: For 7 days after Vaccination 1 and Vaccination 2
Pain at the injection site, redness, and swelling as self-reported in electronic diaries.
SSA: Percentage of participants reporting systemic events
Time frame: For 7 days after Vaccination 1 and Vaccination 2
Fever, fatigue, headache, chills, vomiting, diarrhea, new or worsened muscle pain, and new or worsened joint pain, as self-reported in electronic diaries
SSA: Percentage of participants reporting adverse events
Time frame: From Vaccination 1 to 4 weeks after last vaccination
As elicited by investigational site staff
SSA: Percentage of participants reporting serious adverse events
Time frame: From Vaccination 1 to 6 months after the last study vaccination
As elicited by investigational site staff
SSA: Percentage of participants reporting medically attended adverse event
Time frame: From Vaccination 1 to 6 months after the last study vaccination
As elicited by investigational site staff
SSA: Percentage of participants with abnormal hematology and chemistry laboratory assessments
Time frame: 3 days and 1 week after each vaccination
As measured at the central laboratory
SSA: Percentage of participants with new electrocardiogram (ECG) abnormalities
Time frame: 3 days and 1 week after each vaccination
ECG abnormalities consistent with probable or possible myocarditis or pericarditis, as judged by a cardiologist
SSA: Percentage of participants with abnormal troponin I laboratory values
Time frame: 3 days and 1 week after each vaccination
as measured at the central laboratory
SSB: Percentage of participants reporting local reactions
Time frame: For 7 days after Vaccination 1 and Vaccination 2
Pain at the injection site, redness, and swelling as self-reported in electronic diaries.
SSB: Percentage of participants reporting systemic events
Time frame: For 7 days after Vaccination 1 and Vaccination 2
Fever, fatigue, headache, chills, vomiting, diarrhea, muscle pain, and joint pain, as self-reported in electronic diaries
SSB: Percentage of participants reporting adverse events
Time frame: From Vaccination 1 to 4 weeks after last vaccination
As elicited by investigational site staff
SSB: Percentage of participants reporting serious adverse events
Time frame: From Vaccination 1 to 6 months after the last study vaccination
As elicited by investigational site staff
SSB: Percentage of participants reporting medically attended adverse events
Time frame: From Vaccination 1 to 6 months after the last study vaccination
As elicited by investigational site staff
6 secondary outcomes
SSA: Geometric mean concentrations (GMCs) of glycoprotein E antibodies in proportion of evaluable immunogenicity participant
Time frame: At baseline (before vaccination 1), at 1- and 4-weeks after each vaccination and 6-months after last vaccination
SSA: Geometric mean fold rise (GMFR) from before vaccination to each subsequent timepoint in evaluable immunogenicity participants
Time frame: At baseline (before vaccination 1), at 1- and 4-weeks after each vaccination and 6-months after last vaccination
SSA: Proportion of evaluable immunogenicity participants with vaccine response in glycoprotein E antibodies from baseline to each subsequent timepoint
Time frame: At baseline (before vaccination 1), at 1- and 4-weeks after each vaccination and 6-months after last vaccination
SSB: Geometric mean concentrations (GMCs) of glycoprotein E antibodies in proportion of evaluable immunogenicity participant
Time frame: At baseline (before vaccination 1), at 4-weeks after each vaccination and 6-months after last vaccination
SSB: Geometric mean fold rise (GMFR) from before vaccination to each subsequent timepoint in evaluable immunogenicity participants
Time frame: At baseline (before vaccination 1), at 4-weeks after each vaccination and 6-months after last vaccination
SSB: Proportion of evaluable immunogenicity participants with vaccine response in glycoprotein E antibodies from baseline to each subsequent timepoint
Time frame: At baseline (before vaccination 1), at 4-weeks after each vaccination and 6-months after last vaccination
Results and safety
The study was stopped early (reason given: Strategic decision made by the company). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 May 2026.
- To obtain contact information for a study center near you, click here.Link provided by the sponsor.
- Individual participant dataSharing planned: Yes. Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Pfizer CT.gov Call Center study director
Pfizer
35 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing Candidate 1: PF-07915234: VZV modRNA Powder for Suspension for Injection, Candidate 1: PF-07915234: VZV modRNA Suspension for Injection and Candidate 2: PF-07921188: VZV modRNA Suspension for Injection in people with Shingles and Herpes Zoster Infection, run by Pfizer at 35 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 16 inclusion and 33 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 4 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 35 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study was stopped early (reason given: Strategic decision made by the company). Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
SSA: Percentage of participants reporting local reactions (time frame: For 7 days after Vaccination 1 and Vaccination 2). The study lists 13 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 May 2026.