a study of mrna-1345, an mrna vaccine targeting respiratory syncytial virus, in children 2 to <18 years of age at high risk of respiratory syncytial virus

Conditions: Respiratory Syncytial Virus

Summary: part a: the purpose is to evaluate the safety, reactogenicity, and immunogenicity of mrna-1345 in children aged 2 to \<5 years (cohort 1) and in children at high risk of respiratory syncytial virus (rsv) disease 5 to \<18 years of age (cohort 2) to inform the dose level selection for the next phase of development (phase 3). part b: the purpose is to provide surveillance for rsv disease for the next rsv season (6 months after re-enrollment) and safety follow-up for cohort 1 participants that were enrolled and dosed in part a.


Eligibility criteria:
key inclusion criteria: part a cohort 1: * 2 to \<5 years of age at day 1. * healthy, or with stable chronic conditions increasing the risk of rsv disease, per the clinical judgment of the investigator. cohort 2: * 5 to \<18 years of age at day 1. * participants with stable chronic conditions increasing the risk of rsv disease. * female participants of child-bearing potential may be enrolled in the study, if the participant: 1) has a negative urine pregnancy test at screening and on the day of injection (day 1); 2) has practiced adequate contraception or has abstained from all activities that could lead to pregnancy for 28 days prior to day 1; 3) has agreed to continue adequate contraception through 90 days following injection; and 4) is not currently breastfeeding. part b: cohort 1 re-enrollment participants are eligible to be included in the study only if all of the following criteria apply: 1. enrolled and dosed in part a of cohort 1; either reached eos for part a or were dosed and subsequently discontinued from study for various reasons. this includes participants who were lost to follow-up, if they can be re-engaged. 2. participant's parent(s)/lar(s) has provided written informed consent for participation in this study. key exclusion criteria (all cohorts): * acutely ill or febrile (temperature ≥38.0°celsius \[100.4°fahrenheit\]) within 72 hours prior to or at the screening visit or day 1. * history of a diagnosis or condition that, in the judgment of the investigator, may affect study assessment or compromise participant safety. * has received or plans to receive any licensed or authorized vaccine ≤14 days prior to the study vaccine injection (day 1) or plans to receive a licensed or authorized vaccine within 14 days after the study vaccine injection. * receipt of any prior systemic immunosuppressants. short courses (\<7 days) of oral corticosteroids are allowed if completed at least 3 months prior to enrollment. * receipt of rsv monoclonal antibodies within 6 months prior to enrollment in the study. * participated in an interventional clinical study within 28 days (6 months for a study assessing a product unlicensed/unauthorized in this age group in country of residence at time of enrollment) prior to the day of enrollment or plans to do so while enrolled in this study. part b: cohort 1 re-enrollment 1. participant is currently enrolled in another interventional clinical study. note: other protocol-defined inclusion and exclusion criteria may apply.

Keywords: pediatric mrna-1345 rsv vaccine viral diseases messenger rna moderna