A Study to Evaluate the Safety and Immunogenicity of mRNA-1975 and mRNA-1982 Against Lyme Disease in Participants 18 Through 70 Years of Age

A Phase 1/2, Randomized, Observer-blind, Placebo-controlled, Dose-ranging Study to Evaluate the Safety and Immunogenicity of Heptavalent mRNA-1975 (SR1-7) and Monovalent mRNA-1982 (SR1) in Parallel Against Lyme Disease in Healthy Participants 18 Through 70 Years of Age

The purpose of this study is to evaluate the safety and immunogenicity in parallel of heptavalent mRNA-1975 and monovalent mRNA-1982 against Lyme disease in healthy adult participants.

Inclusion Criteria:

• Body mass index of 18 to 39 kilograms/square meter (inclusive) at the Screening Visit.
• Participants of nonchildbearing potential may be enrolled in the study.
• For female participants of childbearing potential: negative pregnancy test, adequate contraception or has abstained from all activities that could result in pregnancy during the study intervention period, and agreement to continue adequate contraception or abstinence through 3 months following last study injection.

Exclusion Criteria:

• Have chronic illness related to Lyme disease or an active symptomatic Lyme disease infection as suspected or diagnosed by a physician.
• Received treatment for Lyme disease within the prior 3 months.
• Had previous vaccination against Lyme disease or participated in the past in any vaccine study for Lyme disease.
• Had a tick bite within 4 weeks prior to the study injection visit.
• Dermatologic conditions that could affect local solicited AR assessments (for example, tattoos; psoriasis patches affecting skin over the deltoid areas).
• Received systemic immunosuppressants for >14 days in total within 180 days prior to the Screening Visit (for corticosteroids, ≥10 milligrams/day of prednisone or equivalent) or is anticipating the need for systemic immunosuppressive treatment at any time during participation in the study.
• History of myocarditis, pericarditis, or myopericarditis regardless of the timing of past medical history.
• History of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine or intervention that includes one or more of the same components contained in the study injection.
• Has received systemic immunoglobulins, long-acting biological therapies that affect immune responses (for example, infliximab) or blood products within 90 days prior to the Screening Visit or plans to receive them during the study.

Note: Other inclusion and exclusion criteria may apply.