A Study to Evaluate Efficacy, Safety, and Immunogenicity of mRNA-1273 Vaccine in Adults Aged 18 Years and Older to Prevent COVID-19

SARS-CoV-2 Clinical Trial

Official title:

A Phase 3, Randomized, Stratified, Observer-Blind, Placebo-Controlled Study to Evaluate the Efficacy, Safety, and Immunogenicity of mRNA-1273 SARS-CoV-2 Vaccine in Adults Aged 18 Years and Older

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT04470427
• Other study ID #: mRNA-1273-P301
• Secondary ID: 75A50120C00034
• Status: Completed
• Phase: Phase 3
• Start date: July 27, 2020
• Est. completion date: December 29, 2022

Study information

• Verified date: March 2024
• Source: ModernaTX, Inc.
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The mRNA-1273 vaccine is being developed to prevent COVID-19, the disease resulting from Severe Acute Respiratory Syndrome coronavirus (SARS-CoV-2) infection. The study is designed to primarily evaluate the efficacy, safety, and immunogenicity of mRNA-1273 to prevent COVID-19 for up to 2 years after the second dose of mRNA-1273.

Description:

This is a 3-part Phase 3 study, with Part A (Blinded Phase), Part B (Open-label Observational Phase), and Part C (Booster Dose Phase). Participants in Part A are blinded to their treatment assignment, with participants receiving either mRNA-1273 vaccine or placebo. Part B of the study is designed to offer participants to be unblinded so that participants who received placebo in Part A can request 2 doses of open-label mRNA-1273 vaccine. Additionally, participants who choose to be unblinded and were only able to receive 1 dose of mRNA-1273 due to administrative reasons, can choose to receive the second dose of mRNA-1273 during Part B. In Part C, a booster dose will be provided for all eligible participants who choose to receive one.

Please access www.modernatx.com/cove-study for additional information, such as Study Overview, Participation, and Site Locations along with contact numbers for each location for the study.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 30415
• Est. completion date: December 29, 2022
• Est. primary completion date: December 29, 2022
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• (Part A only) Participants who are at high risk of SARS-CoV-2 infection, defined as adults whose locations or circumstances put them at appreciable risk of exposure to SARS-CoV-2 and COVID-19.

• Understands and agrees to comply with the study procedures and provides written informed consent.

• Able to comply with study procedures based on the assessment of the Investigator.

• Female participants of non-childbearing potential may be enrolled in the study. Non-childbearing potential is defined as surgically sterile (history of bilateral tubal ligation, bilateral oophorectomy, hysterectomy) or postmenopausal (defined as amenorrhea for =12 consecutive months prior to Screening without an alternative medical cause). A follicle-stimulating hormone (FSH) level may be measured at the discretion of the Investigator to confirm postmenopausal status.

• Female participants of childbearing potential may be enrolled in the study if the participant fulfills all the following criteria:

• Has a negative pregnancy test at Screening and on the day of the first dose (Day 1, open-label Day 1, and booster dose Day 1).

• Has practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first dose (Day 1).

• Has agreed to continue adequate contraception through 3 months following the last dose (Day 29, open-label Day 29, and booster dose Day 1).

• Is not currently breastfeeding.

• Healthy adults or adults with pre-existing medical conditions who are in stable condition. A stable medical condition is defined as disease not requiring significant change in therapy or hospitalization for worsening disease during the 3 months before enrollment.

• (Part C Only) Is currently enrolled in Part B of the current study (mRNA-1273-P301).

• (Part C Only) Has received at least 1 dose of mRNA-1273 in the current study (mRNA-1273-P301).

Exclusion Criteria:

• Is acutely ill or febrile 72 hours prior to or at Screening or dosing (Part B and Part C). Fever is defined as a body temperature =38.0°Celsius/100.4°Fahrenheit. Participants meeting this criterion may be rescheduled within the relevant window periods. Afebrile participants with minor illnesses can be enrolled/dosed at the discretion of the Investigator.

• Is pregnant or breastfeeding.

• (Part A Only) Known history of SARS-CoV-2 infection.

• Prior (Part A) or concurrent (Part B and Part C) administration of non-study coronavirus (SARS-CoV, Middle East Respiratory Syndrome [MERS]-CoV) vaccine or current/planned simultaneous participation in another interventional study to prevent or treat COVID-19.

• (Part A Only) Demonstrated inability to comply with the study procedures.

• An immediate family member or household member of this study's personnel.

• Known or suspected allergy or history of anaphylaxis, urticaria, or other significant adverse reaction to the vaccine or its excipients.

• Bleeding disorder considered a contraindication to intramuscular injection or phlebotomy.

• Has received or plans to receive a vaccine within 28 days prior to the first dose (Day 1) or plans to receive a non-study vaccine within 28 days prior to or after any dose of investigational product (IP) (except for seasonal influenza vaccine).

• (Part A only) Has participated in an interventional clinical study within 28 days prior to the day of enrollment.

• Immunosuppressive or immunodeficient state, including human immunodeficiency virus (HIV) infection, asplenia, and recurrent severe infections.

• Has received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to IP dose administration (for corticosteroids =20 milligram (mg)/day of prednisone equivalent).

• Has received systemic immunoglobulins or blood products within 3 months prior to the day of IP dose administration.

• Has donated =450 milliliters (mL) of blood products within 28 days prior to IP dose administration.

Related Conditions & MeSH terms

• SARS-CoV-2

Intervention

Biological:
• mRNA-1273
Sterile liquid for injection
• Placebo
0.9% sodium chloride (normal saline) injection

Locations

Country	Name	City	State
United States	Keystone VitaLink Research	Anderson	South Carolina
United States	Children's Healthcare of Atlanta	Atlanta	Georgia
United States	Grady Health System	Atlanta	Georgia
United States	University of Colorado Hospital	Aurora	Colorado
United States	Benchmark Research - Austin	Austin	Texas
United States	Synexus - Optimal Research - Austin	Austin	Texas
United States	Tekton Research	Austin	Texas
United States	University of Maryland School of Medicine	Baltimore	Maryland
United States	Advanced Clinical Research - Rancho Paseo	Banning	California
United States	Meridian Clinical Research	Baton Rouge	Louisiana
United States	Meridian Clinical Research	Binghamton	New York
United States	Ascension St. Vincent Birmingham	Birmingham	Alabama
United States	Synexus Clinical Research US, Inc. - Birmingham	Birmingham	Alabama
United States	Brigham and Women's Hospital	Boston	Massachusetts
United States	Advanced Clinical Research - Be Well MD	Cedar Park	Texas
United States	Hope Research Institute	Chandler	Arizona
United States	University of North Carolina at Chapel Hill	Chapel Hill	North Carolina
United States	Tryon Medical Partners	Charlotte	North Carolina
United States	WR-ClinSearch	Chattanooga	Tennessee
United States	Synexus Clinical Research US, Inc. - Chicago	Chicago	Illinois
United States	UIC Project WISH CRS	Chicago	Illinois
United States	University of Chicago-Hospital	Chicago	Illinois
United States	Cincinnati CRS	Cincinnati	Ohio
United States	New Horizons Clinical Research	Cincinnati	Ohio
United States	Synexus Clinical Research US, Inc. - Cincinnati	Cincinnati	Ohio
United States	Rapid Medical Research Inc	Cleveland	Ohio
United States	Lynn Institute of The Rockies	Colorado Springs	Colorado
United States	Meridian Clinical Research	Dakota Dunes	South Dakota
United States	Global Medical Research - M3 Wake Research	Dallas	Texas
United States	Synexus Clinical Research US, Inc. - Dallas	Dallas	Texas
United States	Hope Clinic of The Emory Vaccine Center	Decatur	Georgia
United States	Accel Research Site	DeLand	Florida
United States	Henry Ford Health System	Detroit	Michigan
United States	Carolina Institute for Clinical Research - M3 Wake Research	Fayetteville	North Carolina
United States	Benchmark Research - Fort Worth	Fort Worth	Texas
United States	University of Texas Medical Branch at Galveston	Galveston	Texas
United States	Synexus Clinical Research US, Inc. - Phoenix West	Glendale	Arizona
United States	Meridian Clinical Research	Grand Island	Nebraska
United States	Keystone VitaLink Research - Greenville	Greenville	South Carolina
United States	Hackensack University Medical Center	Hackensack	New Jersey
United States	Research Centers of America	Hollywood	Florida
United States	Baylor College of Medicine	Houston	Texas
United States	DM Clinical Research - Texas Center For Drug Development	Houston	Texas
United States	Jacksonville Center for Clinical Research	Jacksonville	Florida
United States	Alliance for Multispecialty Research	Knoxville	Tennessee
United States	University of California San Diego	La Jolla	California
United States	eStudySite - La Mesa	La Mesa	California
United States	Laguna Clinical Research	Laredo	Texas
United States	AB Clinical Trials	Las Vegas	Nevada
United States	Clinical Research Center of Nevada	Las Vegas	Nevada
United States	Johnson County Clin-Trials	Lenexa	Kansas
United States	Baptist Health Center for Clinical Research	Little Rock	Arkansas
United States	UCLA Vine Street Clinic CRS	Los Angeles	California
United States	VA Greater Los Angeles Healthcare (veterans only)	Los Angeles	California
United States	Centex Studies	McAllen	Texas
United States	Crisor	Medford	Oregon
United States	Synexus - Optimal Research - Melbourne	Melbourne	Florida
United States	Benchmark Research - Metairie	Metairie	Louisiana
United States	Suncoast Research Group	Miami	Florida
United States	University of Miami	Miami	Florida
United States	Coastal Carolina Research Center	Mount Pleasant	South Carolina
United States	Synexus Clinical Research US, Inc. - Salt Lake City	Murray	Utah
United States	Vanderbilt University Medical Center, Medical Arts Building	Nashville	Tennessee
United States	Vanderbilt University Medical Center, Medical Center North	Nashville	Tennessee
United States	Weill Cornell Chelsea - (CRS)	New York	New York
United States	Weill Cornell Medical College	New York	New York
United States	New Jersey Medical School	Newark	New Jersey
United States	Alliance for Multispecialty Research	Newton	Kansas
United States	Meridian Clinical Research	Norfolk	Nebraska
United States	Lynn Health Science Institute	Oklahoma City	Oklahoma
United States	Meridian Clinical Research	Omaha	Nebraska
United States	Synexus Clinical Research US, Inc. - Orlando	Orlando	Florida
United States	Hope Research Institute	Peoria	Arizona
United States	MediSync Clinical Research Hattiesburg Clinic	Petal	Mississippi
United States	University of Pennsylvania	Philadelphia	Pennsylvania
United States	Hope Research Institute	Phoenix	Arizona
United States	UPMC University Center	Pittsburgh	Pennsylvania
United States	M3 Wake Research, Inc - M3 Wake	Raleigh	North Carolina
United States	Paradigm Clinical Research Institute Inc	Redding	California
United States	Meridian Clinical Research	Rockville	Maryland
United States	Synexus - Optimal Research - Rockville	Rockville	Maryland
United States	Benchmark Research - Sacramento	Sacramento	California
United States	Saint Louis University	Saint Louis	Missouri
United States	Sundance Clinical Research	Saint Louis	Missouri
United States	Foothill Family Clinic - North	Salt Lake City	Utah
United States	Foothill Family Clinic-South Clinic	Salt Lake City	Utah
United States	Benchmark Research - San Angelo	San Angelo	Texas
United States	Clinical Trials of Texas, Inc	San Antonio	Texas
United States	Medical Center For Clinical Research - M3 Wake Research	San Diego	California
United States	Meridian Clinical Research	Savannah	Georgia
United States	Kaiser Permanente - Seattle	Seattle	Washington
United States	Keystone VitaLink Research - Spartanburg	Spartanburg	South Carolina
United States	Clinical Research Atlanta	Stockbridge	Georgia
United States	DM Clinical Research	Tomball	Texas
United States	Quality of Life Medical and Research Center	Tucson	Arizona
United States	George Washington University	Washington	District of Columbia
United States	Palm Beach Research Center	West Palm Beach	Florida
United States	Alliance for Multispecialty Research- East Wichita	Wichita	Kansas
United States	Trial Management Associates	Wilmington	North Carolina
United States	Wake Forest University Health Sciences	Winston-Salem	North Carolina

Sponsors (3)

Lead Sponsor	Collaborator
ModernaTX, Inc.	Biomedical Advanced Research and Development Authority, National Institute of Allergy and Infectious Diseases (NIAID)

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Part A: Number of Participants With a First Occurrence of COVID-19 Starting 14 Days After Second Dose	COVID-19 cases were defined as participants meeting clinical criteria based both on symptoms for COVID-19 and on RT-PCR detection of SARS-CoV-2 from samples collected within 72 hours of the study participant reporting symptoms that met the definition of COVID-19.; An adjudication committee was assembled for the purpose of reviewing potential cases to determine if the criteria for COVID-19 were met.	From Day 43 (14 days after second dose) up to approximately 7 months after the second dose
Primary	Part A: Number of Participants With Solicited Local and Systemic Adverse Reactions (ARs) After First Dose	Solicited ARs (local and systemic) were collected in electronic diary (eDiary) within 7 days of dosing. Local ARs included: pain at injection site, erythema (redness) at injection site, swelling/induration (hardness) at injection site, and localized axillary swelling or tenderness ipsilateral to the injection arm. Systemic ARs included: headache, fatigue, myalgia (muscle aches all over the body), arthralgia (aching in several joints), nausea/vomiting, rash, body temperature (potentially fever), and chills. Severity grading for solicited ARs is based on modified Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventative Vaccine Clinical Trials. Severity was graded 0-4; a lower score indicated lower severity and a higher score indicated greater severity. The Investigator determined if solicited AR was also to be recorded as an AE. Summary of serious AEs (SAEs) and nonserious AEs ("Other"), regardless of causality, is in Reported "Adverse Events" section.	up to Day 7 (7 days after first dose)
Primary	Part A: Number of Participants With Solicited Local and Systemic Adverse Reactions (ARs) After Second Dose	Solicited ARs (local and systemic) were collected in eDiary within 7 days of dosing. Local ARs included: pain at injection site, erythema (redness) at injection site, swelling/induration (hardness) at injection site, and localized axillary swelling or tenderness ipsilateral to the injection arm. Systemic ARs included: headache, fatigue, myalgia (muscle aches all over the body), arthralgia (aching in several joints), nausea/vomiting, rash, body temperature (potentially fever), and chills. Severity grading for solicited ARs is based on modified Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventative Vaccine Clinical Trials. Severity was graded 0-4; lower score indicated lower severity and a higher score indicated greater severity. The Investigator determined if solicited AR was also to be recorded as an AE. Summary of serious AEs (SAEs) and nonserious AEs ("Other"), regardless of causality, is in Reported "Adverse Events" section	Day 29 to Day 35 (from second dose to 7 days after second dose)
Primary	Parts A and B: Number of Participants With Medically Attended AEs (MAAEs) and AEs Leading to Discontinuation	An MAAE is an AE that leads to an unscheduled visit to a healthcare practitioner (HCP). A summary of SAEs and all nonserious AEs ("Other"), regardless of causality, is located in the Reported "Adverse Events" section.	Day 1 (after dosing) through end of study (up to Day 759)
Primary	Parts A and B: Number of Participants With Serious AEs (SAEs)	An SAE was defined as any AE that resulted in death, is life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in disability/permanent damage, was a congenital anomaly/birth defect, or was an important medical event. A summary of SAEs and all nonserious AEs ("Other"), regardless of causality, is located in the Reported "Adverse Events" section.	Day 1 (after dosing) through end of study (up to Day 759)
Secondary	Part A: Number of Participants With Unsolicited AEs up to 28 Days After Any Injection Dose	Unsolicited AE was any AE reported by the participant that was not specified as an AR or was specified as a solicited AR in the protocol but started outside the protocol-defined, post-injection period for reporting solicited ARs. Unsolicited AEs were collected for the 28 days after any injection.; An AE was as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related. A summary of all SAEs and all nonserious AEs ("Other") reported up to the end of the study, regardless of causality, is located in the Reported "Adverse Events" section.	Up to 28 days after any dose
Secondary	Parts A and B: Number of Participants With a First Occurrence of Severe COVID-19 Starting 14 Days After Second Dose	COVID-19 cases were defined as participants meeting clinical criteria based on symptoms for COVID-19 and reverse transcriptase polymerase chain reaction (RT-PCR) detection of SARS-CoV-2 from samples collected within 72 hours of the participant reporting symptoms meeting the definition of COVID-19.; An adjudication committee reviewed potential cases to determine if the criteria for COVID-19 were met.; Clinical signs indicative of severe COVID-19 systemic illness included any of the following: respiratory rate =30 per minute, heart rate =125 beats per minute, oxygen saturation (SpO2) =93% on room air at sea level, or partial pressure of oxygen (PaO2)/fraction of inspired oxygen (FIO2) <300 millimeter of mercury (mm Hg), or respiratory failure or acute respiratory distress syndrome (ARDS), evidence of shock, or significant acute renal, hepatic, or neurologic dysfunction, or admission to an intensive care unit or death.	From Day 43 (14 days after second dose) up to approximately 8 months for Part A and from PDV/unblinding (at 4 months) to up to 8 months for Part B
Secondary	Part A: Number of Participants With a First Occurrence of Either COVID-19 or SARS-CoV-2 Infection Regardless of Symptomatology or Severity Starting 14 Days After Second Dose	COVID-19 cases were defined as participants meeting clinical criteria based both on symptoms for COVID-19 and on RT-PCR detection of SARS-CoV-2 from samples collected within 72 hours of the study participant reporting symptoms that met the definition of COVID-19.; An adjudication committee was assembled for the purpose of reviewing potential cases to determine if the criteria for COVID-19 were met.; SARS-CoV-2 infection was defined by seroconversion due to infection measured by binding antibody (bAb) levels against SARS-CoV-2 nucleocapsid or by positive RT-PCR at predefined timepoints. Seroconversion was defined by the participant's serostatus at baseline.	From Day 43 (14 days after second dose) up to approximately 7 months after the second dose
Secondary	Part A: Number of Participants With a Secondary Case Definition of COVID-19 Starting 14 Days After Second Dose	Secondary case definition of COVID-19 was defined as the presence of at least 1 of the following systemic symptoms: fever (temperature; =38ºC), or chills, cough, shortness of breath or difficulty breathing, fatigue, muscle aches or body aches, headache, new loss of taste or smell, sore throat, nasal congestion or rhinorrhea, nausea or vomiting, or diarrhea and a positive nasopharyngeal swab, nasal swab, or saliva sample (or respiratory sample, if hospitalized) for SARS-CoV-2 by RT-PCR.	From Day 43 (14 days after second dose) up to approximately 7 months after the second dose
Secondary	Parts A and B: Number of Participants Who Died Due to a Cause Directly Attributed to a Complication of COVID-19 Starting 14 Days After Second Dose		From Day 43 (14 days after second dose) up to approximately 8 months for Part A and from PDV/unblinding (at 4 months) to up to 8 months for Part B
Secondary	Part A: Number of Participants With a First Occurrence of COVID-19 Starting 14 Days After First Dose	COVID-19 cases were defined as participants meeting clinical criteria based both on symptoms for COVID-19 and on RT-PCR detection of SARS-CoV-2 from samples collected within 72 hours of the study participant reporting symptoms that met the definition of COVID-19.; An adjudication committee was assembled for the purpose of reviewing potential cases to determine if the criteria for COVID-19 were met.	From 14 days after first dose up to approximately 8 months
Secondary	Part A: Number of Participants With a First Occurrence of COVID-19 Starting 14 Days After Second Dose Regardless of Evidence of Prior SARS-CoV-2 Infection	COVID-19 cases were defined as participants meeting clinical criteria based both on symptoms for COVID-19 and on RT-PCR detection of SARS-CoV-2 from samples collected within 72 hours of the study participant reporting symptoms that met the definition of COVID-19.; An adjudication committee was assembled for the purpose of reviewing potential cases to determine if the criteria for COVID-19 were met.	From Day 43 (14 days after second dose) up to approximately 7 months after the second dose
Secondary	Part A: Number of Participants With a First Occurrence of SARS-CoV-2 Infection in the Absence of Symptoms Defining COVID-19 Starting 14 Days After Second Dose	SARS-CoV-2 infection was defined by seroconversion due to infection measured by binding antibody (bAb) levels against SARS-CoV-2 nucleocapsid or by positive RT-PCR at predefined timepoints. Seroconversion was defined by the participant's serostatus at baseline.	From Day 43 (14 days after second dose) up to approximately 7 months after the second dose
Secondary	Part A: Geometric Mean Titer (GMT) of SARS-CoV-2 Specific Neutralizing Antibody (nAb)	GMT (50% inhibitory dose [ID50], 80% inhibitory dose [ID80]) of nAb against SARS-CoV-2 pseudotyped viruses as measured by pseudovirus nAb assay is reported.; 95% CI was based on the t-distribution of log-transformed values for GM titer, then back transformed to original scale for presentation.; Baseline SARS-CoV-2 Status: Positive if there is immunologic or virologic evidence of prior COVID-19, defined as positive RT-PCR test or positive Elecsys result at Day 1. Negative is defined as negative RT-PCR test and negative Elecsys result at Day 1.	Day 1, Day 29, Day 57
Secondary	Part A: Geometric Mean Fold Rise (GMFR) of SARS-CoV-2 Specific nAb	The GMFR measures the changes in immunogenicity titers or levels from Baseline within participants.; 95% CI was calculated based on the difference in the log-transformed values for GMFR, then back transformed to the original scale for presentation. GMFR for ID50 and ID80 neutralizing antibodies against SARS-CoV-2 S-protein, as measured by pseudovirus neutralizing antibody is presented. Baseline SARS-CoV-2 Status: Positive if there is immunologic or virologic evidence of prior COVID-19, defined as positive RT-PCR test or positive Elecsys result at Day 1. Negative is defined as negative RT-PCR test and negative Elecsys result at Day 1	Day 29, Day 57
Secondary	Part A: Percentage of Participants With Seroresponse Against SARS-CoV-2	Seroresponse to pseudovirus neutralizing antibody ID50 titer at a participant level is defined as a change from below the LLOQ to equal or above the LLOQ, or at least a 3.3-fold rise if baseline is equal to or above the LLOQ. Seroresponse to pseudovirus neutralizing antibody ID80 titer at a participant level is defined as a change from below the LLOQ to equal or above the LLOQ, or at least a 2.3-fold rise if baseline is equal to or above the LLOQ.; Baseline SARS-CoV-2 Status: Positive if there is immunologic or virologic evidence of prior COVID-19, defined as positive RT-PCR test or positive Elecsys result at Day 1. Negative is defined as negative RT-PCR test and negative Elecsys result at Day 1.	Day 29, Day 57
Secondary	Part C: GMT of SARS-CoV-2 Specific nAb Measured by Pseudovirus (VAC62)	95% CI is calculated based on the t-distribution of the log-transformed values for GM value, then back transformed to the original scale for presentation.	Pre-booster (Baseline), post-booster Day 29 and post-booster Day 181
Secondary	Part C: Percentage of Participants With Seroresponse Against SARS-CoV-2 Measured by Pseudovirus (VAC62)	Pseudovirus neutralizing antibody (VAC62) from pre-booster is presented. Seroresponse at a participant level is defined as a change from below the LLOQ to >= 4 x LLOQ, or at least a 4-fold rise if pre-booster is equal to or above the LLOQ.	Post-booster Day 29 and post-booster Day 181
Secondary	Part C: Geometric Mean Concentration (GMC) of SARS-CoV-2 Specific nAb After BD Compared to After Second Dose in Part A Measured by Pseudovirus (VAC62)	95% CI is calculated based on the t-distribution of the log-transformed values for GMC, then back transformed to the original scale for presentation.	Part C BD Day 29 and Part A Day 57
Secondary	Part C: Percentage of Participants With Seroresponse Against SARS-CoV-2 After BD Compared to After Second Dose in Part A	Pseudovirus neutralizing antibody (VAC62) are presented. Seroresponse at a participant level is defined as a change from below the LLOQ to equal or above 4 x LLOQ, or at least a4-fold rise if baseline (Pre- Dose 1) is equal to or above the LLOQ.	Part C BD Day 29 and Part A Day 57