• Had close contact (without personal protective equipment) as defined by the Centers for Disease Control and Prevention (CDC) in the past 14 days to someone diagnosed with SARS-CoV-2 infection or Covid-19 within 10 days of the close contact. Participants could be rescreened after 14 days provided that they remain asymptomatic
• Participant was acutely ill or febrile (temperature ≥38.0°C/100.4°F) 72 hours prior to or at the Screening Visit or day 1. Participants meeting this criterion could be rescheduled within the 28-day screening window and will retain their initially assigned participant number
• Had tested positive for SARS-CoV-2 by an authorized/approved lateral flow/rapid antigen or PCR test within 90 days of Screening
• Had received a Covid-19 vaccine within 90 days of the Screening Visit
• Had received a total of 4 doses or more of Covid-19 vaccine
• Had received a Covid-19 vaccine at a dose different from the authorized/approved dose
• History of a diagnosis or condition that, in the judgment of the Investigator, was clinically unstable or may affect participant safety, assessment of safety endpoints, assessment of immune response, or adherence to study procedures. Clinically unstable was defined as a diagnosis or condition requiring significant changes in management or medication within the 2 months prior to screening and includes ongoing workup of an undiagnosed illness that could lead to a new diagnosis or condition
• Reported history of congenital or acquired immunodeficiency, immunosuppressive condition, or immune-mediated disease requiring immunosuppressive treatment or other immunosuppressive condition
• Dermatologic conditions that could affect local solicited AR assessments (eg, tattoos, psoriasis patches affecting skin over the deltoid areas)
• Reported history of anaphylaxis or severe hypersensitivity reaction after receipt of any components of mRNA vaccine
• Reported history of bleeding disorder that is considered a contraindication to intramuscular injection or phlebotomy
• Any medical, psychiatric, or occupational condition, including reported history of substance abuse, that, in the opinion of the Investigator, might pose additional risk due to participation in the study or could interfere with the interpretation of study results
• Had received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 181 days prior to screening (for corticosteroids ≥10 mg/day of prednisone or equivalent) or was anticipating the need for immunosuppressive treatment at any time during participation in the study
• Had received or planned to receive any licensed vaccine ≤28 days prior to the study injection (day 1) or planned to receive a licensed vaccine within 28 days after the study injection (with the exception that approved seasonal influenza vaccine may be received by at least 7 days and preferably 14 days apart from the study injection)
• Had received systemic immunoglobulins or blood products within 90 days prior to the Screening Visit or plans to receive during the study
• Diagnosis of malignancy within the previous 10 years (excluding nonmelanoma skin cancer)
• Had donated ≥ 450 mL of blood products within 28 days prior to the Screening Visit or planned to donate blood products during the study
• Had participated in an interventional clinical study within 28 days prior to the Screening Visit based on the medical history interview or planned to do so while participating in this study
• Was an immediate family or household member of study personnel, study site staff, or Sponsor personnel.

Protocol

NR

Statistical plan

*

Data-sharing stated: Yes, once the trial is complete
Data accessibility: As the trial is ongoing, access to patient-level data and supporting clinical documents by qualified external researchers may be available upon request and subject to review once the trial is complete. Corresponding author Ivan T. Lee, M.D., Ph.D.: Ivan.Lee@ModernaTx.com