A Study to Investigate Cardiac Troponin Levels After mRNA-1273.712 Vaccine in Participants 12 Through 30 Years of Age

Inclusion criteria

• Investigator's assessment that participant understands and is willing and physically able to comply with protocol-mandated follow-up, including all procedures.
• Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF).
• Contraceptive use by participants should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies.

Exclusion criteria

• History of anaphylaxis or severe hypersensitivity reaction requiring medical intervention after receipt of any mRNA vaccine or therapeutic or any components of an mRNA vaccine or therapeutic.
• Has known history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection within 3 months prior to enrollment.
• Has a documented history of myocarditis or pericarditis.
• Is acutely ill or febrile (temperature ≥38.0 degrees Celsius [°C]/100.4 degrees Fahrenheit [°F]) less than 72 hours prior to or at the Screening Visit or Day 1.
• Has known conditions that may cause elevated cTnI.

• Cardiac disease/conditions including rhythm disorders and congenital heart disease
• Diabetes
• Uncontrolled hypertension (defined as systolic blood pressure >140 millimeter of mercury (mmHg) or diastolic blood pressure >90 mmHg)
• Alcohol or substance abuse
• Kidney disease
• Severe obesity, defined as body mass index (BMI) ≥40 kilograms per square meter (kg/m^2) (>20 years) or severe obesity defined as BMI for sex and age ≥120% of the 95th percentile [BMI ≥35 kg/m^2] (for 12 to 20 years)
• Currently has symptomatic acute or unstable chronic disease requiring medical or surgical care, to include significant change in therapy or hospitalization for worsening disease, at the discretion of the Investigator.
• Has a medical, psychiatric, or occupational condition that may pose additional risk as a result of participation, or that could interfere with safety assessments or interpretation of results according to the Investigator's judgment.
• Reported history of congenital or acquired immunodeficiency (eg, human immunodeficiency virus [HIV]), immunosuppressive condition or immune-mediated disease, asplenia, or recurrent severe infections disease.
• History of Guillain-Barré syndrome.
• Receipt of the following:

• Coronavirus disease 2019 (COVID-19) vaccine within 3 months prior to the first injection or if planning to receive at any time during the study (except for study intervention).
• Any other licensed vaccine within 28 days before the study injection or planned receipt prior to end of study (EOS).
• Systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to Screening (for corticosteroids ≥10 milligrams (mg)/day of prednisone equivalent) or is anticipating the need for immunosuppressive treatment at any time during participation in the study.
• Systemic immunoglobulins or blood products within 3 months prior to the Screening/Baseline Visit or plans for receipt during the study.