Hvidovre Hospital
Hvidovre, Denmark
Not recruiting
Study on the Safety and Immune Response of mRNA-1345 Vaccine for Respiratory Syncytial Virus in Pregnant Women and Their Infants
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What is this trial about?
A plain-language summary of the goals, design and what participants do
This clinical trial is focused on studying a disease called Respiratory Syncytial Virus (RSV), which can cause lung infections, especially in young children and older adults. The study is testing a new vaccine called mRNA-1345, which is designed to help the body fight off RSV. The vaccine is given as an injection into the muscle. Another substance used in the study is a Sodium Chloride Solution 0.9%, which is a common salt solution used in medical treatments.
The purpose of the study is to evaluate how safe the mRNA-1345 vaccine is and how well it works in pregnant women and their babies. The study will look at how the vaccine affects the mothers during pregnancy and how it affects their babies after they are born. Participants in the study will receive either the vaccine or a placebo, and their health will be monitored over time to see if there are any side effects or health changes.
During the study, pregnant women will receive the vaccine and will be observed for any reactions or side effects. After the babies are born, they will also be monitored to see how the vaccine affects them. The study will last for several months, with regular check-ups to ensure the safety and health of both the mothers and their babies. The goal is to gather information that could help in the development of a safe and effective vaccine against Respiratory Syncytial Virus.
The research process
The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.
Who can join the trial?
11 criteria
- Participants must be pregnant women aged 18 to 39 years old at the time of signing the consent form.
- Participants must be receiving and plan to continue receiving antenatal care (medical care during pregnancy).
- Japanese participants are defined as individuals born in Japan, with both parents and four grandparents also born in Japan.
- Participants must have consent from the infant's parent(s) or legal representative if required by local regulations.
- Participants must be willing and able to give written informed consent for themselves and their unborn child before joining the study.
- Participants must be healthy as determined by a medical evaluation, which includes medical history, physical examination, and laboratory tests.
- Participants must be between 280/7 to 360/7 weeks pregnant at the time of vaccination, confirmed by an ultrasound report.
- Participants must plan to live in an area where emergency pediatric care is available through a study-affiliated site.
- Participants must plan to deliver at a maternity unit where study procedures can be performed.
- Participants must be willing and able to attend all study visits, undergo all study procedures, and comply with study requirements, including having a way to communicate with study staff (e.g., phone, text message, or email).
- Participants must give permission for study staff to access their or their infant's relevant medical information from other healthcare facilities if needed.
Who cannot join the trial?
10 criteria
- Participants must not have any known allergies to the components of the vaccine.
- Participants should not have a history of severe allergic reactions, also known as anaphylaxis, to any vaccine.
- Participants must not have any medical conditions that could interfere with the study results.
- Participants should not be currently participating in another clinical trial.
- Participants must not have a history of any significant medical conditions that could affect their safety during the trial.
- Participants should not have any known or suspected immunodeficiency, which means their immune system is not working properly.
- Participants must not have received any other vaccines within a certain period before the study starts.
- Participants should not have any acute illness or fever at the time of enrollment.
- Participants must not be using any medications that could interfere with the immune response to the vaccine.
- Participants should not have a history of drug or alcohol abuse that could affect their ability to follow the study procedures.
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Verified Responsive Region Midtjylland
Aarhus, Denmark
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Investigated drugs
mRNA-1345 is a vaccine designed to protect against a virus called Respiratory Syncytial Virus, or RSV for short. RSV can cause lung infections, especially in young children and older adults. This vaccine uses a technology called mRNA, which helps the body learn how to fight the virus if it encounters it in the future. In this clinical trial, the vaccine is given to pregnant women to see if it is safe and if it helps protect their babies from RSV after they are born. The study looks at how the vaccine affects both the mothers and their infants, focusing on safety and how well it works to prevent RSV infections.
What is already known about the treatment
mRNA-1345 – This medication is an mRNA vaccine designed to protect against the respiratory syncytial virus (RSV). It is administered as an injection, typically given to pregnant women to help protect their infants from RSV after birth. Currently, mRNA-1345 is being studied in clinical trials to assess its safety and effectiveness in both mothers and their newborns. The vaccine works by using a small piece of genetic material called mRNA to instruct cells in the body to produce a protein similar to one found in RSV, which helps the immune system recognize and fight the virus. This vaccine is classified as a preventive treatment for viral infections.
Investigated diseases
Respiratory Syncytial Virus – Respiratory Syncytial Virus (RSV) is a common virus that infects the respiratory tract. It typically causes mild, cold-like symptoms in adults and older children. In infants and young children, it can lead to more severe respiratory illnesses such as bronchiolitis and pneumonia. The virus spreads through respiratory droplets when an infected person coughs or sneezes. RSV infection usually begins with a runny nose, decrease in appetite, coughing, sneezing, fever, and wheezing. The symptoms generally appear in stages and not all at once.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-505359-37-00Protocol codemRNA-1345-P201Estimated enrolment360 patientsSponsorModerna Inc.
sourced from the EU Clinical Trials Register and site verification
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