The purpose of this study is to evaluate whether LY3819253 given alone and with LY3832479 prevent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease - 2019 (COVID-19). Facility staff and residents in contracted skilled nursing and assisted living facility networks with a high risk of SARS-CoV-2 exposure will receive LY3819253, LY3819253 and LY3832479, or placebo via an injection into a vein. Samples will be taken from the nose. Blood samples will be drawn. Participation could last up to 25 weeks and may include up to 19 visits.

Inclusion Criteria:

• Part 1 and Part 2: Resident or facility staff in a skilled nursing or assisted living facility with at least one confirmed case of SARS-CoV-2 detection less than or equal to (≤)7 days prior to randomization

• Are men or non-pregnant women who agree to contraceptive requirements

• Agree to the collection of nasal, mid-turbinate, oropharyngeal, and nasopharyngeal swabs, and venous blood as specified in the schedule of activities

• Have venous access sufficient to allow intravenous infusions and blood sampling

• The participant or legally authorized representative give signed informed consent

• Part 3 only: Resident or staff in a skilled nursing or assisted living facility who satisfy at least one of the following at the time of screening

  • Are greater than or equal to (≥) 65 years of age

  • Have a body mass index (BMI) ≥ 35

  • Have chronic kidney disease

  • Have type 1 or type 2 diabetes

  • Have immunosuppressive disease

  • Are currently receiving immunosuppressive treatment, or

  • Are ≥ 55 years of age AND have

    • cardiovascular disease, OR
    • hypertension, OR
    • chronic obstructive pulmonary disease or other chronic respiratory disease

• Positive SARS-CoV-2 test and infusion within 10 days of symptom onset, OR positive SARS-CoV-2 test and infusion within 10 days of testing if asymptomatic

Exclusion Criteria:

• Parts 1 and 2:

  • Recovered from confirmed COVID-19 disease or asymptomatic infection
  • Prior history of a positive SARS-CoV-2 serology test
  • History of convalescent COVID-19 plasma treatment
  • Participation in a previous SARS-CoV-2 vaccine trial or received an approved SARS-CoV-2 vaccine
  • Previous receipt of SAR-CoV-2-specific monoclonal antibodies

• Have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study

Anonymized individual patient level data will be provided in a secure access environment upon approval of a research proposal and a signed data sharing agreement.

Data are available 6 months after the primary publication and approval of the indication studied in the US and EU, whichever is later. Data will be indefinitely available for requesting.

A research proposal must be approved by an independent review panel and researchers must sign a data sharing agreement.