A Study on the Safety and Immune Response to an mRNA-based RSV Investigational Vaccine in Healthy Adults Aged 18-45 Years

Inclusion Criteria: * Participants, who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g., completion of the eDiary, return for follow-up visits). * Written informed consent obtained from the participant prior to performance of any study-specific procedure. * Healthy participants as established by medical history, clinical examination and laboratory assessment at screening. * Male or female between and including 18 and 45 years of age at the time of enrollment into the study. * Body mass index more than or equal to (\>=) 18 kg/m\^2 and less than (\<) 40 kg/m\^2. * Female participants of non-childbearing potential may be enrolled in the study. * Female participants of childbearing potential may be enrolled in the study if the participant: * has practiced adequate contraception for 1 month prior to study intervention administration period, and * has a negative pregnancy test (on urine sample) on the day of study intervention administration, and * has agreed to continue adequate contraception during the entire treatment period and for at least 1 month after completion of the study intervention administration series. Exclusion Criteria: Medical conditions * History of any reaction or hypersensitivity likely to be exacerbated by any component of the study interventions. * Hypersensitivity to latex. * Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examinat…