*mRNA-1345 safety and immunogenicity in pregnant women and their infants

  • Research type

    Research Study

  • Full title

    *A Phase 2, randomized, observer-blind, placebo-controlled, dose-escalation study to evaluate the reactogenicity, safety, and immunogenicity of mRNA-1345, an mRNA vaccine targeting respiratory syncytial virus, in pregnant women, and safety and immunogenicity in infants born to vaccinated mothers



  • Contact name

    Robert Meehan

  • Contact email


  • Sponsor organisation

    ModernaTX, Inc.

  • Eudract number


  • Research summary

    RSV is a common virus that infects the lungs and respiratory tract and can cause a runny nose, sore throat, cough, and fever. RSV can lead to serious respiratory tract problems like pneumonia and bronchiolitis, especially in young children. Infants under 6 months of age are at greatest risk of developing severe RSV disease due to their immature respiratory and immune systems. In 2019 RSV was associated with over 100,000 deaths of children across the world.
    The only existing RSV preventive strategy in use for this age group are monoclonal antibodies with palivizumab, which is limited in its usage to high-risk infants in the RSV season in high-income countries because of the high cost and short durability, and nirsevimab approved for broad protection against RSV-lower respiratory tract infection in infants, but which is not yet in use.
    An alternative preventive strategy for young infants is maternal vaccination. Studies with RSV vaccines have demonstrated the potential for maternal vaccination to reduce RSV disease in infants born to vaccinated mothers.

    By vaccinating pregnant women with mRNA-1345, the aim is to protect babies from RSV by passing on immunity through the placenta. This approach works for vaccines such as whooping cough, tetanus, flu, and COVID-19.
    This is a randomized, observer-blind trial (study doctor and participants won’t know if a participant is receiving mRNA-1345 or placebo). Participants will receive one injection of either mRNA-1345 or placebo and will have a 25% chance of receiving placebo.
    About 360 pregnant women between the ages of 18 to 40 years old will take part in this clinical trial across 09 countries and 70 sites worldwide.
    The Sponsor of this study is ModernaTX, Inc.

  • REC name

    East of England - Cambridge Central Research Ethics Committee

  • REC reference


  • Date of REC Opinion

    20 Dec 2023

  • REC opinion

    Further Information Favourable Opinion