Pneumococcal InfectionPhase 1NCT07300267
A Clinical Study of Novel Pneumococcal Vaccine V118C in Children (V118C-002)
A Phase 1 study testing V118C (Stage 1), V118C (Stage 2) and PCV20 (Stage 1) in people with Pneumococcal Infection, run by Merck Sharp & Dohme LLC at 15 sites in United States.
Trial summary
Researchers are looking for new vaccines to prevent pneumococcal disease, which is any infection in the lungs or other parts of the body that is caused by a type of bacteria called Streptococcus pneumoniae. V118C is a new vaccine designed to help prevent disease from Streptococcus pneumoniae bacteria. Read more about this study
- Who is it for?
- Ages 2 to 15 monthsHealthy volunteers can take part
- Conditions the study is for
- Pneumococcal Infection
- What is being tested?
- V118C (Stage 1), V118C (Stage 2) and PCV20 (Stage 1)
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 210 participants
- Where
- 15 sitesUnited States
- Study dates
- 13 Jan 2026to 25 May 2029
- Phase
- Phase 1
- Are there results?
- Not yet: the study is under way
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 2 to 15 months
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- The main inclusion criteria include but are not limited to the following:
- Stage 1:
- Is previously vaccinated with 3 routine infant doses of Pneumococcal 20-valent conjugate vaccine (PCV20)
- Is 12 through 15 months of age
- Stage 2:
- Is approximately 2 months of age
- Both Stages:
- Was born at full term (gestational age greater than or equal to 37 weeks)
Who cannot join
- The main exclusion criteria include but are not limited to the following:
- Stage 1:
- Has received a PCV dose at 10 months of age and older
- Stage 2:
- Has received prior administration of any pneumococcal vaccine
- Both stages:
- Has a history of invasive pneumococcal disease (IPD)
- Has a known hypersensitivity to any component of V118C or PCV20 including diphtheria toxoid
Trial locations and contacts
15 sites in 1 country. Contact the study team or a site near you to ask about taking part.
15 sites in 1 country
United States15 sites, 15 recruiting
- Recruiting
Epic Medical Research - Carrollton ( Site 1038)
Carrollton, Texas, 75006
Study Coordinator, 972-777-6956
- Recruiting
Carolina Family Care ( Site 1021)
Charleston, South Carolina, 29414
Study Coordinator, 843-870-2225
- Recruiting
Pediatric Research of Charlottesville, LLC ( Site 1012)
Charlottesville, Virginia, 22902
Study Coordinator, 434-872-9384
- Recruiting
The Pediatric Center ( Site 1025)
Columbia, Maryland, 21045
Study Coordinator, 443-721-7224
- Recruiting
Child Health Care Associates ( Site 1035)
East Syracuse, New York, 13057
Study Coordinator, 315-652-8800
- Recruiting
Epic Medical Research- Garland ( Site 1017)
Garland, Texas, 75043
Study Coordinator, 972-777-6956
- Recruiting
Tribe Clinical Research, LLC-Pediatrics ( Site 1008)
Greenville, South Carolina, 29607
Study Coordinator, 864-334-0141
- Recruiting
University of Texas Medical Branch ( Site 1020)
League City, Texas, 77573
Study Coordinator, 832-340-2313
- Recruiting
University of Louisville, Norton Children's Research Institute ( Site 1005)
Louisville, Kentucky, 40202
Study Coordinator, 502-629-5820
- Recruiting
Madera Family Medical Group ( Site 1004)
Madera, California, 93637
Study Coordinator, 559-673-3000
- Recruiting
Acevedo Clinical Research Associates ( Site 1029)
Miami, Florida, 33142
Study Coordinator, 305-649-8871
- Recruiting
Tribe Clinical Research - Spartanburg ( Site 1001)
Spartanburg, South Carolina, 29301
Study Coordinator, 864-334-0141
- Recruiting
Saint Louis University Center for Vaccine Development ( Site 1031)
St Louis, Missouri, 63104
Study Coordinator, 314-977-6333
- Recruiting
University of South Florida-Department of Pediatrics ( Site 1002)
Tampa, Florida, 33606
Study Coordinator, 813-821-8039
- Recruiting
Cotton O'Neil Research Center ( Site 1039)
Topeka, Kansas, 66604
Study Coordinator, 785-354-6000
About this study
Official title: A Phase 1, Randomized, Double-Blind, Active Comparator Controlled Study to Evaluate the Safety, Tolerability, and Immunogenicity of a Novel Pneumococcal Vaccine in Children
Researchers are looking for new vaccines to prevent pneumococcal disease, which is any infection in the lungs or other parts of the body that is caused by a type of bacteria called Streptococcus pneumoniae. V118C is a new vaccine designed to help prevent disease from Streptococcus pneumoniae bacteria.
This study will look at V118C in toddlers and infants. The goal of the study is to learn how safe V118C is for children and how well they tolerate it.
Read the detailed description
Stage 1 of the study will be conducted in toddlers enrolled at 12 through 15 months of age who previously completed a primary 3-dose infant series with a licensed pneumococcal conjugate vaccine (PCV). Stage 2 will be conducted in infants enrolled at approximately 2 months of age, who will receive the 3+1 schedule (3 infant doses followed by a toddler dose).
- Conditions
- Pneumococcal Infection
- Being tested
- V118C (Stage 1), V118C (Stage 2), PCV20 (Stage 1), PCV20 (Stage 2)
- Medical subject headings
- Pneumococcal Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
V118C (Stage 1)Biological
IM administration of V118C
V118C (Stage 2)Biological
IM administration of V118C
PCV20 (Stage 1)Biological
IM administration of PCV20
PCV20 (Stage 2)Biological
IM administration of PCV20
| Study group | Role | What they receive |
|---|---|---|
| V118C (Stage 1) | Experimental | Participants will receive a single 0.5 mL intramuscular (IM) injection of V118C administered at 12 to 15 months of age. Receives: Biological: V118C (Stage 1) |
| V118C (Stage 2) | Experimental | Participants will receive a single 0.5 mL IM injection of V118C administered at 2,4,6, and 12 months of age. Receives: Biological: V118C (Stage 2) |
| PCV20 (Stage 1) | Active comparator | Participants will receive a single 0.5 mL IM injection of PCV20 administered at 12 to 15 months of age. Receives: Biological: PCV20 (Stage 1) |
| PCV20 (Stage 2) | Active comparator | Participants will receive a single 0.5 mL IM injection of PCV20 administered at 2,4,6, and 12 months of age. Receives: Biological: PCV20 (Stage 2) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Stage 1: Percentage of Participants With Immediate Adverse Events (AEs) Following Vaccination
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Percentage of participants with immediate AEs following vaccination will be reported.
Measured: Up to approximately 30 minutes postvaccination
Stage 1: Percentage of Participants With Solicited Injection-Site Adverse Events (AEs)
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. A solicited AE is a predefined event that participants legally acceptable representative (LAR) are specifically asked about and record on their electronic vaccine report card (eVRC). Solicited injection-site AEs include redness, swelling, pain or tenderness and hard lump. Percentage of participants with solicited injection-site AEs will be reported.
Measured: Up to approximately 7 days postvaccination
Stage 1: Percentage of Participants With Solicited Systemic AEs
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. A solicited AE is a predefined event that participants LAR are specifically asked about and record on their eVRC. Solicited systemic AEs include irritability, drowsiness, appetite lost, hives or welts, and fever. Percentage of participants with solicited systemic AEs will be reported.
Measured: Up to approximately 7 days postvaccination
Stage 1: Percentage of Participants With Unsolicited Systemic or Injection-Site AEs
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An unsolicited AE is an event that is not solicited using a eVRC and that is communicated by a participant. Percentage of participants with unsolicited Systemic or Injection-Site AEs will be reported.
Measured: Up to approximately 28 days postvaccination
Stage 1: Percentage of Participants With Serious Adverse Events (SAEs)
A serious adverse event (SAE) is an AE that is life-threatening, requires or prolongs an existing hospitalization, results in persistent or significant disability or incapacity, is a congenital anomaly or birth defect, or is another important medical event deemed such by medical or scientific judgment. Percentage of participants with one or more SAEs will be reported.
Measured: Up to approximately 12 months postvaccination
Stage 1: Percentage of Participants With Medically Attended AEs (MAAEs)
A MAAE is defined as an adverse event in which medical attention is received during an unscheduled, non-routine outpatient visit, such as an emergency department visit, office visit, or an urgent care visit with any medical personnel for any reason. Percentage of participants with MAAEs will be reported.
Measured: Up to approximately 12 months postvaccination
Stage 2: Percentage of Participants With Immediate AEs Following Vaccination
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Percentage of participants with immediate AEs following vaccination will be reported.
Measured: Up to approximately 30 minutes after each vaccination
Stage 2: Percentage of Participants With Solicited Injection-Site AEs
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. A solicited AE is a predefined event that participants LAR are specifically asked about and record on their eVRC. Solicited injection-site AEs include redness, swelling, pain or tenderness and hard lump. Percentage of participants with solicited injection-site AEs will be reported.
Measured: Up to approximately 7 days after each vaccination
Stage 2: Percentage of Participants With Solicited Systemic AEs
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. A solicited AE is a predefined event that participants LAR are specifically asked about and record on their eVRC. Solicited systemic AEs include irritability, drowsiness, appetite lost, hives or welts, and fever. Percentage of participants with solicited systemic AEs will be recorded.
Measured: Up to approximately 7 days after each vaccination
Stage 2: Percentage of Participants With Unsolicited Systemic or Injection-Site AEs
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An unsolicited AE is an event that is not solicited using a eVRC and that is communicated by a participant. Percentage of participants with unsolicited Systemic or Injection-Site AEs will be reported.
Measured: Up to approximately 28 days after each vaccination
Stage 2: Percentage of Participants With SAEs
A SAE is an AE that is life-threatening, requires or prolongs an existing hospitalization, results in persistent or significant disability or incapacity, is a congenital anomaly or birth defect, or is another important medical event deemed such by medical or scientific judgment. Percentage of participants with one or more SAEs will be reported.
Measured: Up to approximately 12 months postdose 4
Stage 2: Percentage of Participants With MAAEs
A MAAE is defined as an adverse event in which medical attention is received during an unscheduled, non-routine outpatient visit, such as an emergency department visit, office visit, or an urgent care visit with any medical personnel for any reason. Percentage of participants with MAAEs will be reported.
Measured: Up to approximately 12 months postdose 4
Secondary outcomes (14)
Stage 1: Geometric Mean Concentrations (GMCs) of Serotype-Specific Immunoglobulin G (IgG)
The GMCs for serotype-specific IgG antibodies will be determined using pneumococcal electrochemiluminescence (Pn ECL) assay. GMCs of Serotype-specific IgG at 30 days postvaccination with V118C and PCV20 will be reported.
Measured: Up to approximately 30 days post vaccination
Stage 1: Ratio of GMCs of Serotype-Specific IgG of V118C to PCV20 [V118C/PCV20]
The GMCs for serotype-specific IgG antibodies will be determined using pneumococcal electrochemiluminescence (Pn ECL) assay. Ratio of GMCs of serotype-specific IgG of V118C to PCV20 will be reported.
Measured: Approximately Day 30 postvaccination
Stage 1: Geometric Mean Fold Rises (GMFRs) of Serotype-Specific Immunoglobulin G (IgG)
Geometric mean fold rise (GMFR) is defined as the geometric mean of the ratio of concentration at Day 30 after vaccination divided by concentration at baseline. GMFRs of serotype-specific IgG from baseline (Day 1) to Day 30 with V118C and PCV20 for IgG responses will be reported.
Measured: Day 1 (Baseline) and approximately Day 30 postvaccination
Stage 1: Percentage of Participants With a ≥ 4-fold Rise for Serotype Specific IgG Concentrations
The percentage of participants with ≥4-fold rise from baseline (Day 1) to Day 30 with V118C and PCV20 for IgG responses will be reported.
Measured: Day 1 (Baseline) and approximately Day 30 postvaccination
Stage 2: Percentage of Participants With IgG ≥0.35 μg/mL (Response Rates) for Serotype Specific IgG Concentrations at 30 Days Postdose 3
Percentage of participants with IgG ≥0.35 μg/mL (response rates) for each serotype at 30 days postdose 3 (PD3) with V118C and PCV20 will be reported will be reported.
Measured: Up to approximately 30 days postdose 3
Stage 2: Percentage of Participants With IgG ≥0.35 μg/mL (Response Rates) for Serotype Specific IgG Concentrations at 30 Days Predose 4
Percentage of participants with IgG ≥0.35 μg/mL (response rates) for each serotype at predose 4 (PD4) with V118C and PCV20 will be reported.
Measured: Up to approximately 6 months post dose 3
Stage 2: Percentage of Participants With IgG ≥0.35 μg/mL (Response Rates) for Serotype Specific IgG Concentrations at 30 Days Postdose 4
Percentage of participants with IgG ≥0.35 μg/mL (response rates) for each serotype at 30 days postdose 4 with V118C and PCV20 will be reported.
Measured: Up to approximately 30 days postdose 4
Stage 2: Difference in the Response Rates [V118C minus PCV20] for Each Serotype at 30 Days Postdose 3
Difference in the response rates [V118C minus PCV20] for each serotype at 30 days postdose 3 with V118C and PCV20 will be reported.
Measured: Up to approximately 30 days postdose 3
Stage 2: Difference in the Response Rates [V118C Minus PCV20] for Each Serotype at 30 Days Postdose 4
Difference in the response rates [V118C minus PCV20] for each serotype at 30 days postdose 4 with V118C and PCV20 will be reported.
Measured: Up to approximately 30 days postdose 4
Stage 2: GMCs of Serotype-Specific IgG at 30 Days Postdose 3
The GMCs for serotype-specific IgG antibodies will be determined using pneumococcal electrochemiluminescence (Pn ECL) assay. GMCs of serotype-specific IgG at 30 days postdose 3 with V118C and PCV20 will be reported.
Measured: Up to approximately 30 days postdose 3
Stage 2: GMCs of Serotype-Specific IgG at 30 Days Predose 4
The GMCs for serotype-specific IgG antibodies will be determined using pneumococcal electrochemiluminescence (Pn ECL) assay. Serotype-specific IgG GMCs at 30 days predose 4 with V118C and PCV20 will be reported.
Measured: Up to approximately 6 months post dose 3
Stage 2: GMCs of Serotype-Specific IgG at 30 Days Postdose 4
The GMCs for serotype-specific IgG antibodies will be determined using pneumococcal electrochemiluminescence (Pn ECL) assay. Serotype-specific IgG GMCs at 30 days postdose 4 with V118C and PCV20 will be reported.
Measured: Up to approximately 30 days postdose 4
Stage 2: Ratio of Serotype-Specific IgG GMCs of V118C to PCV20 [V118C/PCV20] at 30 Days Postdose 3
The GMCs for serotype-specific IgG antibodies will be determined using pneumococcal electrochemiluminescence (Pn ECL) assay. Ratio of serotype-specific IgG GMCs of V118C to PCV20 [V118C/PCV20] at 30 days postdose 3 will be reported.
Measured: Up to approximately 30 days postdose 3
Stage 2: Ratio of Serotype-Specific IgG GMCs of V118C to PCV20 [V118C/PCV20] at 30 Days Postdose 4
The GMCs for serotype-specific IgG antibodies will be determined using pneumococcal electrochemiluminescence (Pn ECL) assay. Ratio of serotype-specific IgG GMCs of V118C to PCV20 [V118C/PCV20] at 30 days postdose 4 will be reported.
Measured: Up to approximately 30 days postdose 4
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Dec 2025
- Study start13 Jan 2026
- Primary completion24 Oct 2028 (estimated)
- Study completion25 May 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pneumococcal InfectionStudies of the same condition, open and under way.
- More trials run by Merck Sharp & Dohme LLCThe 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
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 210 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Merck Sharp & Dohme LLC
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Merck Sharp & Dohme LLC
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07300267
- Sponsor's protocol ID
- V118C-002
- Status last verified
- Sep 2026
- First submitted
- 10 Dec 2025
- Last updated
- 2 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
Study at a glance
From the registry record, last updated by the sponsor on 2 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1, Randomized, Double-Blind, Active Comparator Controlled Study to Evaluate the Safety, Tolerability, and Immunogenicity of a Novel Pneumococcal Vaccine in Children
- ClinicalTrials.gov ID
- NCT07300267
- Acronym / sponsor ID
- V118C-002
- Conditions
- Pneumococcal Infection
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 210 participants (estimated)
- Lead sponsor
- Merck Sharp & Dohme LLCIndustry (pharma, biotech, devices)
- Study start
- 13 Jan 2026 (actual)
- Primary completion
- 24 Oct 2028 (estimated)
- Study completion
- 25 May 2029 (estimated)
- First posted
- 23 Dec 2025 (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.
Researchers are looking for new vaccines to prevent pneumococcal disease, which is any infection in the lungs or other parts of the body that is caused by a type of bacteria called Streptococcus pneumoniae. V118C is a new vaccine designed to help prevent disease from Streptococcus pneumoniae bacteria.
This study will look at V118C in toddlers and infants. The goal of the study is to learn how safe V118C is for children and how well they tolerate it.
Detailed description
Stage 1 of the study will be conducted in toddlers enrolled at 12 through 15 months of age who previously completed a primary 3-dose infant series with a licensed pneumococcal conjugate vaccine (PCV). Stage 2 will be conducted in infants enrolled at approximately 2 months of age, who will receive the 3+1 schedule (3 infant doses followed by a toddler dose).
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| V118C (Stage 1) | Experimental | Biological: V118C (Stage 1)Participants will receive a single 0.5 mL intramuscular (IM) injection of V118C administered at 12 to 15 months of age. |
| V118C (Stage 2) | Experimental | Biological: V118C (Stage 2)Participants will receive a single 0.5 mL IM injection of V118C administered at 2,4,6, and 12 months of age. |
| PCV20 (Stage 1) | Active comparator | Biological: PCV20 (Stage 1)Participants will receive a single 0.5 mL IM injection of PCV20 administered at 12 to 15 months of age. |
| PCV20 (Stage 2) | Active comparator | Biological: PCV20 (Stage 2)Participants will receive a single 0.5 mL IM injection of PCV20 administered at 2,4,6, and 12 months of age. |
Who may qualify
- Ages
- 2 to 15 months
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (8 listed)
- Is previously vaccinated with 3 routine infant doses of Pneumococcal 20-valent conjugate vaccine (PCV20)
- Is 12 through 15 months of age
- Is approximately 2 months of age
- Was born at full term (gestational age greater than or equal to 37 weeks)
Key exclusion criteria (8 listed)
- Has received a PCV dose at 10 months of age and older
- Has received prior administration of any pneumococcal vaccine
- Has a history of invasive pneumococcal disease (IPD)
- Has a known hypersensitivity to any component of V118C or PCV20 including diphtheria toxoid
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 |
|---|---|---|
| V118C (Stage 1)IM administration of V118C | Biological | V118C (Stage 1) |
| V118C (Stage 2)IM administration of V118C | Biological | V118C (Stage 2) |
| PCV20 (Stage 1)IM administration of PCV20 | Biological | PCV20 (Stage 1) |
| PCV20 (Stage 2)IM administration of PCV20 | Biological | PCV20 (Stage 2) |
Primary outcome
Stage 1: Percentage of Participants With Immediate Adverse Events (AEs) Following Vaccination
Time frame: Up to approximately 30 minutes postvaccination
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Percentage of participants with immediate AEs following vaccination will be reported.
Stage 1: Percentage of Participants With Solicited Injection-Site Adverse Events (AEs)
Time frame: Up to approximately 7 days postvaccination
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. A solicited AE is a predefined event that participants legally acceptable representative (LAR) are specifically asked about and record on their electronic vaccine report card (eVRC). Solicited injection-site AEs include redness, swelling, pain or tenderness and hard lump. Percentage of participants with solicited injection-site AEs will be reported.
Stage 1: Percentage of Participants With Solicited Systemic AEs
Time frame: Up to approximately 7 days postvaccination
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. A solicited AE is a predefined event that participants LAR are specifically asked about and record on their eVRC. Solicited systemic AEs include irritability, drowsiness, appetite lost, hives or welts, and fever. Percentage of participants with solicited systemic AEs will be reported.
Stage 1: Percentage of Participants With Unsolicited Systemic or Injection-Site AEs
Time frame: Up to approximately 28 days postvaccination
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An unsolicited AE is an event that is not solicited using a eVRC and that is communicated by a participant. Percentage of participants with unsolicited Systemic or Injection-Site AEs will be reported.
Stage 1: Percentage of Participants With Serious Adverse Events (SAEs)
Time frame: Up to approximately 12 months postvaccination
A serious adverse event (SAE) is an AE that is life-threatening, requires or prolongs an existing hospitalization, results in persistent or significant disability or incapacity, is a congenital anomaly or birth defect, or is another important medical event deemed such by medical or scientific judgment. Percentage of participants with one or more SAEs will be reported.
Stage 1: Percentage of Participants With Medically Attended AEs (MAAEs)
Time frame: Up to approximately 12 months postvaccination
A MAAE is defined as an adverse event in which medical attention is received during an unscheduled, non-routine outpatient visit, such as an emergency department visit, office visit, or an urgent care visit with any medical personnel for any reason. Percentage of participants with MAAEs will be reported.
Stage 2: Percentage of Participants With Immediate AEs Following Vaccination
Time frame: Up to approximately 30 minutes after each vaccination
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Percentage of participants with immediate AEs following vaccination will be reported.
Stage 2: Percentage of Participants With Solicited Injection-Site AEs
Time frame: Up to approximately 7 days after each vaccination
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. A solicited AE is a predefined event that participants LAR are specifically asked about and record on their eVRC. Solicited injection-site AEs include redness, swelling, pain or tenderness and hard lump. Percentage of participants with solicited injection-site AEs will be reported.
Stage 2: Percentage of Participants With Solicited Systemic AEs
Time frame: Up to approximately 7 days after each vaccination
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. A solicited AE is a predefined event that participants LAR are specifically asked about and record on their eVRC. Solicited systemic AEs include irritability, drowsiness, appetite lost, hives or welts, and fever. Percentage of participants with solicited systemic AEs will be recorded.
Stage 2: Percentage of Participants With Unsolicited Systemic or Injection-Site AEs
Time frame: Up to approximately 28 days after each vaccination
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An unsolicited AE is an event that is not solicited using a eVRC and that is communicated by a participant. Percentage of participants with unsolicited Systemic or Injection-Site AEs will be reported.
Stage 2: Percentage of Participants With SAEs
Time frame: Up to approximately 12 months postdose 4
A SAE is an AE that is life-threatening, requires or prolongs an existing hospitalization, results in persistent or significant disability or incapacity, is a congenital anomaly or birth defect, or is another important medical event deemed such by medical or scientific judgment. Percentage of participants with one or more SAEs will be reported.
Stage 2: Percentage of Participants With MAAEs
Time frame: Up to approximately 12 months postdose 4
A MAAE is defined as an adverse event in which medical attention is received during an unscheduled, non-routine outpatient visit, such as an emergency department visit, office visit, or an urgent care visit with any medical personnel for any reason. Percentage of participants with MAAEs will be reported.
14 secondary outcomes
Stage 1: Geometric Mean Concentrations (GMCs) of Serotype-Specific Immunoglobulin G (IgG)
Time frame: Up to approximately 30 days post vaccination
Stage 1: Ratio of GMCs of Serotype-Specific IgG of V118C to PCV20 [V118C/PCV20]
Time frame: Approximately Day 30 postvaccination
Stage 1: Geometric Mean Fold Rises (GMFRs) of Serotype-Specific Immunoglobulin G (IgG)
Time frame: Day 1 (Baseline) and approximately Day 30 postvaccination
Stage 1: Percentage of Participants With a ≥ 4-fold Rise for Serotype Specific IgG Concentrations
Time frame: Day 1 (Baseline) and approximately Day 30 postvaccination
Stage 2: Percentage of Participants With IgG ≥0.35 μg/mL (Response Rates) for Serotype Specific IgG Concentrations at 30 Days Postdose 3
Time frame: Up to approximately 30 days postdose 3
Stage 2: Percentage of Participants With IgG ≥0.35 μg/mL (Response Rates) for Serotype Specific IgG Concentrations at 30 Days Predose 4
Time frame: Up to approximately 6 months post dose 3
Stage 2: Percentage of Participants With IgG ≥0.35 μg/mL (Response Rates) for Serotype Specific IgG Concentrations at 30 Days Postdose 4
Time frame: Up to approximately 30 days postdose 4
Stage 2: Difference in the Response Rates [V118C minus PCV20] for Each Serotype at 30 Days Postdose 3
Time frame: Up to approximately 30 days postdose 3
Stage 2: Difference in the Response Rates [V118C Minus PCV20] for Each Serotype at 30 Days Postdose 4
Time frame: Up to approximately 30 days postdose 4
Stage 2: GMCs of Serotype-Specific IgG at 30 Days Postdose 3
Time frame: Up to approximately 30 days postdose 3
Stage 2: GMCs of Serotype-Specific IgG at 30 Days Predose 4
Time frame: Up to approximately 6 months post dose 3
Stage 2: GMCs of Serotype-Specific IgG at 30 Days Postdose 4
Time frame: Up to approximately 30 days postdose 4
Stage 2: Ratio of Serotype-Specific IgG GMCs of V118C to PCV20 [V118C/PCV20] at 30 Days Postdose 3
Time frame: Up to approximately 30 days postdose 3
Stage 2: Ratio of Serotype-Specific IgG GMCs of V118C to PCV20 [V118C/PCV20] at 30 Days Postdose 4
Time frame: Up to approximately 30 days postdose 4
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Oct 2026.
- Merck Clinical Trials InformationLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
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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.
Medical Director study director
Merck Sharp & Dohme LLC
15 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing V118C (Stage 1), V118C (Stage 2) and PCV20 (Stage 1) in people with Pneumococcal Infection, run by Merck Sharp & Dohme LLC at 15 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 8 inclusion and 8 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: looking for participants now, as of the sponsor's last update on 2 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 15 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 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.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Toll Free Number (1-888-577-8839, Trialsites@msd.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Stage 1: Percentage of Participants With Immediate Adverse Events (AEs) Following Vaccination (time frame: Up to approximately 30 minutes postvaccination). The study lists 12 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 2 Oct 2026.