Healthy Volunteers  Inclusion Criteria:  Is male or non-pregnant female adult ≥ 18 and ≤ 55 years of age Has a body mass index (BMI) < 35 kg/m2. Is healthy as determined by medical history and physical examination Agrees to use contraception through 3 months after the last dose of IGM-6268  Exclusion Criteria:  Receipt of any COVID-19 vaccine during this study and follow-up period Prior positive SARS-CoV2 test Hepatitis B virus (HBV), hepatitis C virus (HCV), or uncontrolled human immunodeficiency virus (HIV) infection Use of any nasally administered drug  Mild-Moderate COVID Patients  Inclusion Criteria:  Is male or non-pregnant female adult ≥ 18 and ≤ 55 years of age Agrees to use contraception through 3 months after the last dose of IGM-6268 Agrees to the collection of blood, urine, saliva, and nasopharyngeal samples, per protocol. Signs and symptoms of mild to moderate COVID-19 but not requiring hospitalization Has a laboratory-confirmed SARS-CoV-2 infection as determined by FDA-authorized antigen or NAAT diagnostic assay during the period of 72 hours prior to enrollment.  Exclusion Criteria:  Receipt of any COVID-19 vaccine during this study and follow-up period Receipt of remdisivir, antiviral antibody treatment (plasma or Mabs), immosuppressive therapies, or cytokine-targeted anti-inflammatory drugs Concurrent use of drugs not approved for use in COVID-19 patients (e.g., ivermectin, chloroquine/hydroxychloroquine, budesonide). Co-morbidities including but not limited to hypertension, cardiovascular disease, diabetes (Type 1 or 2), chronic kidney disease, or asthma Subject is considered to be in their last few weeks of life prior to this acute illness Cancer within the last 5 years except stable prostate cancer and basal cell carcinoma Hepatitis B virus (HBV), hepatitis C virus (HCV), or uncontrolled human immunodeficiency virus (HIV) infection Influenza or confirmed or suspected pulmonary or systemic bacterial infection Receipt of any COVID-19 vaccine during this study and follow-up period Use of any nasally administered drug