A Study to Evaluate the Immunogenicity and Safety of mRNA Vaccine Boosters for SARS-CoV-2 (COVID-19) Variants

ModernaTX, Inc.5,161 enrolled

Overview

This is a study to evaluate the immunogenicity, safety, and reactogenicity of mRNA-1273.211, mRNA-1273, mRNA-1273.617.2, mRNA-1273.213, mRNA-1273.529, mRNA-1273.214, mRNA-1273.222, mRNA-1273.815, and mRNA-1273.231 administered as booster doses.

This clinical study will consist of 9 parts: A (1 and 2), B, C, D, E, F, G, H, and J. Part A.1 will evaluate 2 dose levels of the mRNA-1273.211 vaccine when administered as a single booster dose to adult participants of the mRNA-1273-P301 (COVE \[NCT04470427\]) study who have previously received 2 doses of mRNA-1273. Part A.2 will evaluate the immunogenicity, safety, and reactogenicity of the mRNA-1273.214 vaccine candidate when administered as a second booster dose to adult participants of the mRNA-1273-P205 study who have previously received 2 doses of mRNA-1273 as a primary series and a first booster of (50 μg total mRNA content) of the mRNA-1273.211 in Part A.1 of this study. Part B will evaluate the mRNA-1273 vaccine when administered as a single booster dose to adult participants of the mRNA-1273-P301 (COVE \[NCT04470427\]) study who have previously received 2 doses of mRNA-1273. Part C will evaluate 2 dose levels of the mRNA-1273.617.2 vaccine when administered as a single booster dose to adult participants of the mRNA-1273-P301 (COVE \[NCT04470427\]) study who have previously received 2 doses of mRNA-1273. Part D will evaluate 2 dose levels of the mRNA-1273.213 vaccine when administered as a single booster dose to adult participants of the mRNA-1273-P301 (COVE \[NCT04470427\]) study who have previously received 2 doses of mRNA-1273. Part E will be enrolled at a single clinical study site. Part E will evaluate the mRNA-1273.213 vaccine when administered as a single booster dose to adult participants who have previously received 2 doses of any SARS-CoV-2 mRNA authorized vaccine, including mRNA-1273. Part F will consist of 2 cohorts: Cohort 1 will consist of adults who have previously received 2 doses of mRNA-1273 as primary series. Cohort 1 will evaluate the mRNA-1273.529 vaccine as a single booster dose. Cohort 2 will consist of adults who have previously received 2 doses of mRNA-1273 as a primary series and a single booster dose of mRNA-1273 in study mRNA-1273-P301 (COVE \[NCT04470427\]) or under the emergency use authorization (EUA). Cohort 2 will evaluate the mRNA-1273.529 and mRNA-1273 vaccines as a single booster dose. Part G will evaluate the mRNA1273.214 vaccine candidate when administered as a second booster dose to adults who have previously received 2 doses of mRNA-1273 as a primary series and a single booster dose of mRNA-1273. Part H will evaluate the immunogenicity, safety, and reactogenicity of the mRNA- 1273.222 vaccine candidate when administered as a second booster dose to adults who have previously received 2 doses of mRNA-1273 as a primary series and a single booster dose of mRNA-1273. Part J will evaluate mRNA-1273.815 and mRNA-1273.231 when administered as a booster dose to adults who previously received a primary series of mRNA vaccine, a first booster dose of a monovalent mRNA vaccine, and a second booster dose of a bivalent mRNA vaccine against SARS-COV-2.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

PREVENTION

Masking

NONE

Enrollment

5,161

Conditions

SARS-CoV-2

Interventions

mRNA-1273.211BIOLOGICAL

Sterile liquid for injection

mRNA-1273BIOLOGICAL

Sterile liquid for injection

mRNA-1273.617.2BIOLOGICAL

Sterile liquid for injection

mRNA-1273.213

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Key Inclusion Criteria: * For female participants of childbearing potential: negative pregnancy test, adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to Day 1, agreement to continue adequate contraception or abstinence through 3 months following the vaccination, and not currently breastfeeding. * Participants must have been either previously enrolled in the mRNA-1273-P301 (COVE) study, must have received 2 doses of mRNA-1273 in that study, with their second dose at least 6 months prior to enrollment in this study (mRNA-1273-P205), and must be currently enrolled and compliant in that study (that is, has not withdrawn or discontinued early); or participant must have received 2 doses of mRNA-1273 under the EUA with their second dose at least 6 months prior to enrollment in mRNA-1273-P205; or have received a 2 dose primary series of mRNA-1273 followed by a 50 μg booster dose of mRNA-1273 in the mRNA-1273-P301 (COVE) study or under EUA at least 3 months prior to enrolment in mRNA-1273-P205; and able to provide proof of vaccination status at the time of screening (Day 1); or for enrollment in Part A.2, participant must be currently enrolled and compliant in Part A.1 of the mRNA 1273 P205 study and must have received their first booster dose of mRNA 1273.211 50 μg; or for enrollment in Part J, participant must meet at least 1 of the following criteria: completed enrollment in Part H of the mRNA-1273-P205 study; or received a 2-dose primary series of mRNA-1273 (100 μg) followed by a 50 μg booster dose of mRNA-1273 in the mRNA-1273-P301 (COVE) study or under EUA, followed by a 50 μg booster dose of mRNA-1273.222 under EUA at least 3 months prior to enrollment in Part J of mRNA-1273-P205; or previously received a 2-dose primary series of mRNA vaccine against SARS-CoV-2 followed by a booster dose of a monovalent mRNA vaccine, followed by a second booster dose of a bivalent mRNA vaccine. Participants in Part J must also provide proof of vaccination status at the time of screening (Day 0 or Day 1). Key Exclusion Criteria: * Significant exposure to someone with SARS-CoV-2 infection or COVID-19 in the past 14 days, as defined by the US Centers for Disease Control and Prevention (CDC) as a close contact of someone who has had COVID-19. * Known history of SARS-CoV-2 infection within 3 months prior to enrollment. * Is acutely ill or febrile (temperature ≥38.0°Celsius/\[100.4°Fahrenheit\]) less than 72 hours prior to or at the Screening Visit (Day 0) or Day 1. * Has a medical, psychiatric, or occupational condition that may pose additional risk as a result of participation, or that could interfere with safety assessments or interpretation of results according to the investigator's judgment. * Has received systemic immunosuppressants or immune-modifying drugs for \>14 days in total within 6 months prior to Screening (for corticosteroids ≥10 milligrams (mg)/day of prednisone equivalent) or is anticipating the need for immunosuppressive treatment at any time during participation in the study. * Known or suspected allergy or history of anaphylaxis, urticaria, or other significant AR to the vaccine or its excipients. * Has a documented history of myocarditis or pericarditis within 2 months prior to Screening Visit (Day 0). * Has received or plans to receive any licensed vaccine ≤28 days prior to the injection (Day 1) or a licensed vaccine within 28 days before or after they study injection, with the exception of influenza vaccines, which may be given 14 days before or after receipt of a study vaccine. * Has received systemic immunoglobulins or blood products within 3 months prior to the Screening Visit (Day 0) or plans for receipt during the study. * Has donated ≥450 milliliters (mL) of blood products within 28 days prior to the Screening Visit (Day 0) or plans to donate blood products during the study. * Is currently experiencing an SAE in Study mRNA-1273-P301 (COVE) at the time of screening for this study. Note: Other inclusion and exclusion criteria may apply.

Locations (23)

Benchmark Research (California)

Sacramento, California, United States

Outcomes

Primary Outcomes

Number of Participants With Solicited Local and Systemic ARs

Solicited ARs (local and systemic) were collected in an electronic diary (eDiary). Local ARs included: injection site pain, injection site erythema (redness), injection site swelling/induration (hardness), and axillary (underarm) swelling or tenderness ipsilateral to the side of injection. Systemic ARs included: fever, headache, fatigue, myalgia, arthralgia, nausea/vomiting, and chills. All solicited ARs considered causally related to injection were graded 0-4 (per Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials); lower score indicates lower severity, and a higher score indicates greater severity. The Investigator reviewed whether the solicited AR was also to be recorded as an adverse event (AE). A Summary of serious AEs (SAEs) and nonserious AEs ("Other"), regardless of causality, is located in the "Reported Adverse Events" section.

Time frame: 7 days post-vaccination

Number of Participants With Unsolicited AEs

An AE was defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related. Any abnormal laboratory test result (hematology, clinical chemistry, or prothrombin time \[PT\]/partial thromboplastin time \[PTT\]) or other safety assessment (for example, electrocardiogram, radiological scan, vital sign measurement), including one that worsened from baseline and was considered clinically significant in the medical and scientific judgment of the Investigator was recorded as an AE. Number of participants with unsolicited AEs (SAEs and non-serious AEs) up to 28 days post-vaccination are reported in this outcome measure.

Time frame: Up to 28 days post-vaccination

Number of Participants With SAEs, AEs of Special Interest (AESIs), Medically Attended AEs (MAAEs), and AEs Leading to Study or Treatment Discontinuation

An SAE was defined as any AE that resulted in death, was 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. AESIs included thrombocytopenia, new onset of or worsening of the protocol specified neurologic diseases, anaphylaxis, and myocarditis/pericarditis. An MAAE is an AE that lead to an unscheduled visit to a healthcare practitioner. This included visits to a study site for unscheduled assessments (for example, abnormal laboratory follow-up, and/or coronavirus disease 2019 \[COVID-19\] and visits to healthcare practitioners external to the study site (for example, urgent care, primary care physician). Number of participants with SAEs, AESIs, MAAEs, and AEs leading to discontinuation up to the end of study (EOS) are reported in this outcome measure.

Data from ClinicalTrials.gov

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Sterile liquid for injection

mRNA-1273.529BIOLOGICAL

Sterile liquid for injection

mRNA-1273.214BIOLOGICAL

Sterile liquid for injection

mRNA-1273.222BIOLOGICAL

Sterile liquid for injection

mRNA-1273.815BIOLOGICAL

Sterile liquid for injection

mRNA-1273.231BIOLOGICAL

Sterile liquid for injection

Research Centers of America

Hollywood, Florida, United States

Jacksonville Center For Clinical Research

Jacksonville, Florida, United States

Meridian Clinical Research-(Savannah Georgia)

Savannah, Georgia, United States

Meridian Clinical Research (Iowa)

Sioux City, Iowa, United States

Johnson County Clinical Trials

Lenexa, Kansas, United States

Meridian Clinical Research-(Baton Rouge, Louisiana)

Baton Rouge, Louisiana, United States

Benchmark Research

Metairie, Louisiana, United States

Meridian Clinical Research-(Rockville Maryland)

Rockville, Maryland, United States

Brigham and Women's Hospital

Boston, Massachusetts, United States

...and 13 more locations

Time frame: Day 1 to EOS (Day 366 for Parts A.1, B, C, D, E, and F; and Day 181 for Parts A.2, H, and J)

Geometric Mean Titer (GMT) of Serum Pseudovirus Neutralizing Antibody (nAb) ID50 Titers Against Omicron BA.1 Variant and Ancestral SARS-CoV-2 at Day 29 - mRNA-1273.214 (50 μg) (Part A.2) Compared to mRNA-1273.211 (50 μg) (Part A.1)

GMT of serum pseudovirus nAb ID50 titers against Omicron BA.1 Variant (B.1.1.529) and ancestral severe acute respiratory syndrome coronavirus (SARS-CoV-2) (D614G) at Day 29 is reported. mRNA-1273.214 (50 μg) as a second booster dose (Part A.2) was compared to mRNA-1273.211 (50 μg) as the first booster dose (Part A.1). Antibody values reported as below the lower limit of quantification (LLOQ) were replaced by 0.5 \* LLOQ. Values greater than the upper limit of quantification (ULOQ) were replaced by the ULOQ if actual values were not available. LLOQ was 19.85 arbitrary units (AU)/milliliter (mL) and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 29

GMT of Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant and Ancestral SARS-CoV-2 at Day 181 - mRNA-1273.214 (50 μg) (Part A.2) Compared to mRNA-1273.211 (50 μg) (Part A.1)

GMT of serum pseudovirus nAb ID50 titers against Omicron BA.1 Variant (B.1.1.529) and ancestral SARS-CoV-2 (D614G) at Day 181 is reported. mRNA-1273.214 (50 μg) as a second booster dose (Part A.2) was compared to mRNA-1273.211 (50 μg) as the first booster dose (Part A.1). Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 181

Seroresponse Rate (SRR) (Based on Pre-vaccination Baseline) For Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant and Ancestral SARS-CoV-2 at Day 29 - mRNA-1273.214 (50 μg) (Part A.2) Compared to mRNA-1273.211 (50 μg) (Part A.1)

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) and ancestral SARS-CoV-2 (D614G) at Day 29 are reported. mRNA-1273.214 (50 μg) as a second booster dose (Part A.2) was compared to mRNA-1273.211 (50 μg) as the first booster dose (Part A.1). Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 29

SRR (Based on Pre-booster Baseline) For Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant and Ancestral SARS-CoV-2 at Day 29 - mRNA-1273.214 (50 μg) (Part A.2) Compared to mRNA-1273.211 (50 μg) (Part A.1)

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) and ancestral SARS-CoV-2 (D614G) at Day 29 are reported. mRNA-1273.214 (50 μg) as a second booster dose (Part A.2) was compared to mRNA-1273.211 (50 μg) as the first booster dose (Part A.1). Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 29

SRR (Based on Pre-vaccination Baseline) For Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant and Ancestral SARS-CoV-2 at Day 181 - mRNA-1273.214 (50 μg) (Part A.2) Compared to mRNA-1273.211 (50 μg) (Part A.1)

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) and ancestral SARS-CoV-2 (D614G) at Day 181 are reported. mRNA-1273.214 (50 μg) as a second booster dose (Part A.2) was compared to mRNA-1273.211 (50 μg) as the first booster dose (Part A.1). Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 181

SRR (Based on Pre-booster Baseline) For Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant and Ancestral SARS-CoV-2 at Day 181 - mRNA-1273.214 (50 μg) (Part A.2) Compared to mRNA-1273.211 (50 μg) (Part A.1)

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) and ancestral SARS-CoV-2 (D614G) at Day 181 are reported. mRNA-1273.214 (50 μg) as a second booster dose (Part A.2) was compared to mRNA-1273.211 (50 μg) as the first booster dose (Part A.1). Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 181

GMT of Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) at Day 29 - Part F (Cohort 2): mRNA-1273.529 and mRNA-1273

GMT of serum pseudovirus nAb ID50 titers against Omicron BA.1 Variant (B.1.1.529) at Day 29 is reported. Part F (Cohort 2) mRNA-1273.529 50 μg was compared to Part F (Cohort 2) mRNA-1273 50 μg. Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529.

Time frame: Day 29

SRR (Based on Pre-vaccination Baseline) for Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) at Day 29 - Part F (Cohort 2): mRNA-1273.529 and mRNA-1273

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) at Day 29 are reported. Part F (Cohort 2) mRNA-1273.529 50 μg was compared to Part F (Cohort 2) mRNA-1273 50 μg. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529.

Time frame: Day 29

SRR (Based on Pre-booster Baseline) for Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) at Day 29 - Part F (Cohort 2): mRNA-1273.529 and mRNA-1273

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) at Day 29 are reported. Part F (Cohort 2) mRNA-1273.529 50 μg was compared to Part F (Cohort 2) mRNA-1273 50 μg. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529.

Time frame: Day 29

GMT of Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) and Ancestral SARS-CoV-2 (D614G) at Day 29 - mRNA-1273.214 (Part G) Compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

GMT of serum pseudovirus nAb ID50 titers against Omicron BA.1 Variant (B.1.1.529) and ancestral SARS-CoV-2 (D614G) at Day 29 is reported. mRNA-1273.214 (Part G) was compared the mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273). Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 29

GMT of Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) and Ancestral SARS-CoV-2 (D614G) at Day 91 - mRNA-1273.214 (Part G) Compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

GMT of serum pseudovirus nAb ID50 titers against Omicron BA.1 Variant (B.1.1.529) and ancestral SARS-CoV-2 (D614G) at Day 91 is reported. mRNA-1273.214 (Part G) was compared the mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273). Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 91

SRR (Based on the Pre-vaccination Baseline) for Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) at Day 29 - mRNA-1273.214 (Part G) Compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) at Day 29 are reported. mRNA-1273.214 (Part G) was compared the mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273). Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529.

Time frame: Day 29

SRR (Based on the Pre-booster Baseline) for Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) at Day 29 - mRNA-1273.214 (Part G) Compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) at Day 29 are reported. mRNA-1273.214 (Part G) was compared the mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273). Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529.

Time frame: Day 29

SRR (Based on the Pre-vaccination Baseline) for Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) at Day 91 - mRNA-1273.214 (Part G) Compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) at Day 91 are reported. mRNA-1273.214 (Part G) was compared the mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273). Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529.

Time frame: Day 91

SRR (Based on the Pre-booster Baseline) for Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) at Day 91 - mRNA-1273.214 (Part G) Compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) at Day 91 are reported. mRNA-1273.214 (Part G) was compared the mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273). Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529.

Time frame: Day 91

GMT of Serum Pseudovirus nAb ID50 Titers Against Omicron BA.4/BA.5 Variant and Ancestral SARS-CoV-2 (D614G) at Day 29 - mRNA-1273.222 (Part H) Compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

GMT of serum pseudovirus nAb ID50 titers against BA.4/BA.5 and ancestral SARS-CoV-2 (D614G) at Day 29 is reported. mRNA-1273.222 (Part H) was compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273). Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 29

SRR (Based on Pre-vaccination Baseline) for Serum Pseudovirus nAb ID50 Titers Against Omicron BA.4/BA.5 Variant and Ancestral SARS-CoV-2 (D614G) at Day 29 - mRNA-1273.222 (Part H) Compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against BA.4/BA.5 and ancestral SARS-CoV-2 (D614G) at Day 29 are reported. mRNA-1273.222 (Part H) was compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273). Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 29

SRR (Based on Pre-booster Baseline) for Serum Pseudovirus nAb ID50 Titers Against Omicron BA.4/BA.5 Variant and Ancestral SARS-CoV-2 (D614G) at Day 29 - mRNA-1273.222 (Part H) Compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against BA.4/BA.5 and ancestral SARS-CoV-2 (D614G) at Day 29 are reported. mRNA-1273.222 (Part H) was compared to mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273). Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 29

GMT of Serum Pseudovirus nAb ID50 Titers Against SARS-CoV-2 XBB.1.5, BA.4/BA.5, and SARS-CoV-2 BQ.1.1 at Day 15 - Part J: mRNA-1273.231 and mRNA-1273.815

GMT of serum pseudovirus nAb ID50 titers against SARS-CoV-2 XBB.1.5, BA.4/BA.5, and SARS-CoV-2 BQ.1.1 at Day 15 is reported. Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. Antibody values reported as below the lower limit of detection (LOD) are replaced by 0.5 \* LOD. LOD was 10 AU/mL for ID50 titer against XBB.1.5 and BQ.1.1. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5.

Time frame: Day 15

GMT of Serum Pseudovirus nAb ID50 Titers Against SARS-CoV-2 XBB.1.5, BA.4/BA.5, and SARS-CoV-2 BQ.1.1 at Day 29 - Part J: mRNA-1273.231 and mRNA-1273.815

GMT of serum pseudovirus nAb ID50 titers against SARS-CoV-2 XBB.1.5, BA.4/BA.5, and SARS-CoV-2 BQ.1.1 at Day 29 is reported. Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. Antibody values reported as below the LOD are replaced by 0.5 \* LOD. LOD was 10 AU/mL for ID50 titer against XBB.1.5 and BQ.1.1. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5.

Time frame: Day 29

Geometric Mean Fold Rise (GMFR) of Serum Pseudovirus nAb ID50 Titers Against SARS-CoV-2 XBB.1.5, BA.4/BA.5, and SARS-CoV-2 BQ.1.1 at Day 15 - Part J: mRNA-1273.231 and mRNA-1273.815

GMFR of serum pseudovirus nAb ID50 titers against SARS-CoV-2 XBB.1.5, BA.4/BA.5, and SARS-CoV-2 BQ.1.1 at Day 15 is reported. GMFR measures the changes in immunogenicity titers or levels from Baseline within participants. Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. Antibody values reported as below the LOD are replaced by 0.5 \* LOD. LOD was 10 AU/mL for ID50 titer against XBB.1.5 and BQ.1.1. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5.

Time frame: Day 15

GMFR of Serum Pseudovirus nAb ID50 Titers Against SARS-CoV-2 XBB.1.5, BA.4/BA.5, and SARS-CoV-2 BQ.1.1 at Day 29 - Part J: mRNA-1273.231 and mRNA-1273.815

GMFR of serum pseudovirus nAb ID50 titers against SARS-CoV-2 XBB.1.5, BA.4/BA.5, and SARS-CoV-2 BQ.1.1 at Day 29 is reported. GMFR measures the changes in immunogenicity titers or levels from Baseline within participants. Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. Antibody values reported as below the LOD are replaced by 0.5 \* LOD. LOD was 10 AU/mL for ID50 titer against XBB.1.5 and BQ.1.1. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5

Time frame: Day 29

SRR (Based on the Pre-vaccination Baseline) for Serum Pseudovirus nAb ID50 Titers Against BA.4/BA.5 at Day 15 - Part J: mRNA-1273.231 and mRNA-1273.815

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against BA.4/BA.5 at Day 15 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5.

Time frame: Day 15

SRR (Based on the Pre-booster Baseline) for Serum Pseudovirus nAb ID50 Titers Against BA.4/BA.5 at Day 15 - Part J: mRNA-1273.231 and mRNA-1273.815

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against BA.4/BA.5 at Day 15 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5.

Time frame: Day 15

SRR (Based on the Pre-vaccination Baseline) for Serum Pseudovirus nAb ID50 Titers Against BA.4/BA.5 at Day 29 - Part J: mRNA-1273.231 and mRNA-1273.815

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against BA.4/BA.5 at Day 29 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5.

Time frame: Day 29

SRR (Based on the Pre-booster Baseline) for Serum Pseudovirus nAb ID50 Titers Against BA.4/BA.5 at Day 29 - Part J: mRNA-1273.231 and mRNA-1273.815

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against BA.4/BA.5 at Day 29 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5.

Time frame: Day 29

Secondary Outcomes

GMT of Serum Pseudovirus nAb ID50 Titers Against Ancestral SARS-CoV-2 (D614G) at Day 29 - Part F (Cohort 2): mRNA-1273.529 and mRNA-1273

GMT of serum pseudovirus nAb ID50 titers against ancestral SARS-CoV-2 (D614G) at Day 29 is reported. Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 29

SRR (Based on the Pre-vaccination Baseline) for Serum Pseudovirus nAb ID50 Titers Against Ancestral SARS-CoV-2 (D614G) at Day 29 - Part F (Cohort 2): mRNA-1273.529 and mRNA-1273

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against ancestral SARS-CoV-2 (D614G) at Day 29 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 29

SRR (Based on the Pre-booster Baseline) for Serum Pseudovirus nAb ID50 Titers Against Ancestral SARS-CoV-2 (D614G) at Day 29 - Part F (Cohort 2): mRNA-1273.529 and mRNA-1273

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against ancestral SARS-CoV-2 (D614G) at Day 29 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 29

SRR (Based on the Pre-vaccination Baseline) for Serum Pseudovirus nAb ID50 Titers Against Ancestral SARS-CoV-2 (D614G) on Days 29, 91, 181, and 366 - mRNA-1273.214 (Part G) and mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against ancestral SARS-CoV-2 (D614G) on Days 29, 91, 181, and 366 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Days 29, 91, 181, and 366

SRR (Based on the Pre-booster Baseline) for Serum Pseudovirus nAb ID50 Titers Against Ancestral SARS-CoV-2 (D614G) on Days 29, 91, 181, and 366 - mRNA-1273.214 (Part G) and mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against ancestral SARS-CoV-2 (D614G) on Days 29, 91, 181, and 366 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Days 29, 91, 181, and 366

GMT of Serum Pseudovirus nAb ID50 Titers Against BA.4/BA.5 at Day 181 - mRNA-1273.222 (Part H)

GMT of serum pseudovirus nAb ID50 titers against BA.4/BA.5 at Day 181 is reported. Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5.

Time frame: Day 181

GMT of Serum Pseudovirus nAb ID50 Titers Against Ancestral SARS-CoV-2 (D614G) at Day 181 - mRNA-1273.222 (Part H) and mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

GMT of serum pseudovirus nAb ID50 titers against ancestral SARS-CoV-2 (D614G) at Day 181 is reported. Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 181

SRR (Based on Pre-vaccination Baseline) for Serum Pseudovirus nAb ID50 Titers Against BA.4/BA.5 at Day 181 - mRNA-1273.222 (Part H)

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against BA.4/BA.5 at Day 181 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5.

Time frame: Day 181

SRR (Based on Pre-vaccination Baseline) for Serum Pseudovirus nAb ID50 Titers Against Ancestral SARS-CoV-2 (D614G) at Day 181 - mRNA-1273.222 (Part H) and mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against ancestral SARS-CoV-2 (D614G) at Day 181 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 181

SRR (Based on Pre-booster Baseline) for Serum Pseudovirus nAb ID50 Titers Against BA.4/BA.5 at Day 181 - mRNA-1273.222 (Part H)

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against BA.4/BA.5 at Day 181 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 36.7 AU/mL and ULOQ was 13705 AU/mL for ID50 titer against BA.4/BA.5.

Time frame: Day 181

SRR (Based on Pre-booster Baseline) for Serum Pseudovirus nAb ID50 Titers Against Ancestral SARS-CoV-2 (D614G) at Day 181 - mRNA-1273.222 (Part H) and mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against ancestral SARS-CoV-2 (D614G) at Day 181 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Day 181

SRR (Based on the Pre-vaccination Baseline) for Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) at Days 181 and 366 - mRNA-1273.214 (Part G) and mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-vaccination baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) at Days 181 and 366 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529.

Time frame: Days 181 and 366

SRR (Based on the Pre-booster Baseline) for Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) at Days 181 and 366 - mRNA-1273.214 (Part G) and mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

Percentage of participants with seroresponse (based on the pre-booster baseline) for pseudovirus nAb ID50 against Omicron BA.1 Variant (B.1.1.529) at Days 181 and 366 are reported. Seroresponse was defined as a change from below the LLOQ to equal above 4 \* LLOQ, or at least a 4-fold rise if baseline is equal to or above the LLOQ. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529.

Time frame: Days 181 and 366

GMT of Serum Pseudovirus nAb ID50 Titers Against Omicron BA.1 Variant (B.1.1.529) and Ancestral SARS-CoV-2 (D614G) on Days 181 and 366 - mRNA-1273.214 (Part G) and mRNA-1273 (Part F, Cohort 2, 50 μg mRNA-1273)

GMT of serum pseudovirus nAb ID50 titers against Omicron BA.1 Variant (B.1.1.529) and ancestral SARS-CoV-2 (D614G) on Days 181 and 366 is reported. Antibody values reported as below the LLOQ were replaced by 0.5 \* LLOQ. Values greater than the ULOQ were replaced by the ULOQ if actual values were not available. LLOQ was 19.85 AU/mL and ULOQ was 15502.7 AU/mL for ID50 titer against B.1.1.529. LLOQ was 18.5 AU/mL and ULOQ was 45118 AU/mL for ID50 titer against ancestral SARS-CoV-2.

Time frame: Days 181 and 366