A Study of mRNA-1345 Vaccine Targeting Respiratory Syncytial Virus in Pregnant Women and in Infants Born to Vaccinated Mothers

NCT ID: NCT06143046

Last Updated: 2026-02-05

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

ACTIVE_NOT_RECRUITING

Clinical Phase

PHASE2

Total Enrollment

360 participants

Study Classification

INTERVENTIONAL

Study Start Date

2023-11-15

Study Completion Date

2026-05-27

Brief Summary

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The purpose of the study is to evaluate the reactogenicity, safety, and immunogenicity of an investigational respiratory syncytial virus (RSV) vaccine, mRNA-1345, in pregnant women, and safety and immunogenicity in infants born to vaccinated mothers.

Detailed Description

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Conditions

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Respiratory Syncytial Virus

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

PREVENTION

Blinding Strategy

QUADRUPLE

Participants Caregivers Investigators Outcome Assessors
Observer-blind study

Study Groups

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mRNA-1345 Dose A

Participants will be vaccinated in the period from 28 weeks to 36 weeks of gestation with a single intramuscular (IM) injection of mRNA-1345 Dose A.

Group Type EXPERIMENTAL

mRNA-1345

Intervention Type BIOLOGICAL

Sterile liquid for injection

mRNA-1345 Dose B

Participants will be vaccinated in the period from 28 weeks to 36 weeks of gestation with a single IM injection of mRNA-1345 Dose B.

Group Type EXPERIMENTAL

mRNA-1345

Intervention Type BIOLOGICAL

Sterile liquid for injection

mRNA-1345 Dose C

Participants will be vaccinated in the period from 28 weeks to 36 weeks of gestation with a single IM injection of mRNA-1345 Dose C.

Group Type EXPERIMENTAL

mRNA-1345

Intervention Type BIOLOGICAL

Sterile liquid for injection

Placebo

Participants will receive single IM injection of mRNA-1345 vaccine matching placebo in the period from 28 weeks to 36 weeks of gestation.

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type BIOLOGICAL

0.9% sodium chloride (normal saline) injection

Interventions

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mRNA-1345

Sterile liquid for injection

Intervention Type BIOLOGICAL

Placebo

0.9% sodium chloride (normal saline) injection

Intervention Type BIOLOGICAL

Eligibility Criteria

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Inclusion Criteria

Maternal Participants

* Are adults ≥18 years to \<40 years of age inclusive, at the time of signing the informed consent.
* Will be 28 to 36 weeks pregnant at the time of vaccination (confirmed by an obstetric ultrasound report).
* Intend to deliver at a maternity unit where study procedures can be performed.
* Are willing and able to attend all study visits, to undergo all study procedures/or have their infant undergo all study procedures, and to comply with study requirements, including a means of communication (for example, phone, text message or email) with study site staff.
* Have engaged with local antenatal care and will continue to do so through the remainder of their pregnancy.
* Have had an antenatal obstetric ultrasound at ≥18 weeks of pregnancy or be willing to have an antenatal obstetric ultrasound at Screening if not already conducted.


* Japanese participants are defined as individuals born in Japan, with both parents and 4 grandparents who were born in Japan.

Infant Participants

* Have consent from infant participant's parent(s)/legally authorized representative (LAR) if required by local regulations.

Exclusion Criteria

Maternal Participants

* Acutely ill or febrile (temperature ≥38.0 degrees Celsius \[℃\]/100.4 degrees Fahrenheit \[°F\]) within 72 hours prior to or at the Screening Visit or Day 1.
* Reported history of anaphylaxis or severe hypersensitivity reaction after receipt of any mRNA vaccine or therapeutic or any components of an mRNA-1345 vaccine.
* Any medical, psychiatric, or occupational condition, including reported history of drug or alcohol abuse, that, in the opinion of the Investigator, might pose additional risk due to participation in the study or could interfere with the interpretation of study results.
* Have conditions in the current pregnancy or in previous pregnancies that may affect participant safety, assessment of safety endpoints, assessment of immune response, or adherence to study procedures.
* Received or plans to receive any mRNA vaccine or COVID-19 vaccine within 4 weeks before or after Day 1 and/or any other nonstudy vaccine within 2 weeks before or after Day 1.
* Previous vaccination with any licensed or investigational RSV vaccine or planned receipt during study participation.
* Intend for their infant to receive RSV monoclonal antibodies after delivery.

Infant Participants

* Is a child who has been placed under the control or protection of an agency, organization, institution, or entity by the courts, the government, or a government body acting in accordance with powers conferred on them by laws and regulation (for example, foster care). This does not include a child who is adopted or has an appointed LAR.
Minimum Eligible Age

0 Years

Maximum Eligible Age

40 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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ModernaTX, Inc.

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Locations

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SEC Clinical Research LLC - Dothan 2 - ClinEdge - PPDS

Dothan, Alabama, United States

Site Status

Abby's Research Institute

Phoenix, Arizona, United States

Site Status

Watching Over Mothers & Babies

Tucson, Arizona, United States

Site Status

Applied Research Center of Arkansas - ClinEdge - PPDS

Little Rock, Arkansas, United States

Site Status

Matrix Clinical Research - Gardena

Gardena, California, United States

Site Status

Matrix Clinical Research - Huntington Park

Huntington Park, California, United States

Site Status

Matrix Clinical Research, Inc - Corporate Office

Los Angeles, California, United States

Site Status

Clinical Research Prime - ClinEdge - PPDS

Idaho Falls, Idaho, United States

Site Status

Bingham Memorial Hospital

Pocatello, Idaho, United States

Site Status

Clinical Research Prime - ClinEdge - Rexburg - PPDS

Rexburg, Idaho, United States

Site Status

Velocity Clinical Research - Covington - PPDS

Covington, Louisiana, United States

Site Status

Saginaw Valley Medical Research Group LLC

Saginaw, Michigan, United States

Site Status

Boeson Research GTF - Great Falls - ERN - PPDS

Great Falls, Montana, United States

Site Status

Boeson Research KAL - Kalispell - ERN - PPDS

Kalispell, Montana, United States

Site Status

Boeson Research MSO - Missoula - ERN - PPDS

Missoula, Montana, United States

Site Status

Velocity Clinical Research (Grand Island - Nebraska) - PPDS

Grand Island, Nebraska, United States

Site Status

Velocity Clinical Research (Hastings - Nebraska) - PPDS

Hastings, Nebraska, United States

Site Status

Velocity Clinical Research (Norfolk - Nebraska) - PPDS

Norfolk, Nebraska, United States

Site Status

DM Clinical Research - Bellaire - ERN - PPDS

Houston, Texas, United States

Site Status

Maximos OB/GYN

League City, Texas, United States

Site Status

SMS Clinical Research

Mesquite, Texas, United States

Site Status

Maternal Fetal Diagnostics Center

Salt Lake City, Utah, United States

Site Status

Dalhousie University - 5820 University Ave

Halifax, Nova Scotia, Canada

Site Status

Ottawa Hospital

Ottawa, Ontario, Canada

Site Status

Sainte Justine Hospital

Montreal, Quebec, Canada

Site Status

Centre Hospitalier de l'Université Laval

Québec, , Canada

Site Status

Clínica Universidad de los Andes

Las Condes, Región-MetropolitanadeSantiago, Chile

Site Status

Centro Internacional de Estudios Clínicos

Recoleta, Región-MetropolitanadeSantiago, Chile

Site Status

Red Hospital Clinico de la Universidad de Chile

Santiago, , Chile

Site Status

Hvidovre Hospital

Hvidovre, Capital, Denmark

Site Status

Aarhus Universitetshospital

Aarhus, Central Jutland, Denmark

Site Status

Regionshospitalet Gødstrup

Herning, Central Jutland, Denmark

Site Status

Shonan Kamakura General Hospital

Kamakura-Shi, Kanagawa, Japan

Site Status

Saiseikai Yokohamashi Nanbu Hospital

Yokohama, Kanagawa, Japan

Site Status

Saitama City Hospital

Saitama-Shi, Saitama, Japan

Site Status

Center Hospital of the National Center for Global Health and Medicine

Shinjuku-Ku, Tokyo, Japan

Site Status

Centro De Vacunacion Internacional, S.A. (Cevaxin) - David

David, Chiriquí Province, Panama

Site Status

Centro De Vacunacion Internacional, S.A. (Cevaxin) Sede La Chorrera

Panama City, , Panama

Site Status

Centro De Vacunacion Internacional, S.A. (Cevaxin)

Panama City, , Panama

Site Status

CEVAXIN 24 de diciembre

Panama City, , Panama

Site Status

Instituto de Investigaciones Científicas Y Servicios de Alta Tecnología Asociación de Interés Panama

Pueblo Nuevo, , Panama

Site Status

Josha Research

Bloemfontein, Free State, South Africa

Site Status

Drs. YAK Vahed & Partners

Welkom, Free State, South Africa

Site Status

Ubuntu Clinical Research

Krugersdorp, Gauteng, South Africa

Site Status

Bothe ke Bontle Health Services-316 Kuit st

Pretoria, Gauteng, South Africa

Site Status

Setshaba Research Centre

Soshanguve, Gauteng, South Africa

Site Status

WITS Clinical Research Site - PPDS

Soweto, Gauteng, South Africa

Site Status

Merclinico Middelburg

Middelburg, Mpumalanga, South Africa

Site Status

FAM-CRU

Cape Town, Western Cape, South Africa

Site Status

Royal Bournemouth Hospital

Bournemouth, Dorset, United Kingdom

Site Status

Southampton General Hospital

Southampton, Hampshire, United Kingdom

Site Status

The Royal London Hospital

London, London, City of, United Kingdom

Site Status

The Royal Free Hospital

London, Middlesex, United Kingdom

Site Status

Cardiff & Vale University Health Board-PPDS

Cardiff, South Glamorgan, United Kingdom

Site Status

St George's Hospital

London, Surrey, United Kingdom

Site Status

Glasgow Clinical Research Facility - PPDS

Glasgow, , United Kingdom

Site Status

Countries

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United States Canada Chile Denmark Japan Panama South Africa United Kingdom

Other Identifiers

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2023-505359-37-00

Identifier Type: OTHER

Identifier Source: secondary_id

mRNA-1345-P201

Identifier Type: -

Identifier Source: org_study_id

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