SARS-CoV-2-Neutralizing Monoclonal COVID-19 Antibody DZIF-10c by Inhalation

Inclusion Criteria: Groups 1A-1C * Age 18-65. * SARS-CoV-2-RNA negative naso- or oropharyngeal swab obtained within 3 calendar days before study drug administration by NAAT (e.g., qRT-PCR). * Non-reactivity of serum antibodies (IgG; and IgA and/or IgM when tested) against SARS-CoV-2 by serological assay at screening. Groups 2A-2D * Age 18-70. * SARS-CoV-2-RNA positive naso- or oropharyngeal swab obtained within 3 calendar days before study drug administration by NAAT (e.g., qRT-PCR). * Onset of COVID-19 symptoms (e.g., sore throat, cough, fever, chills, fatigue, dys- or anosmia, dys- or ageusia, headache, muscle pain, gastrointestinal symptoms) within 7 days prior to study drug administration or Non-reactivity of serum or plasma antibodies (IgG; and IgA and/or IgM when tested) against SARS-CoV-2 by serological assay at screening. * Disease severity score 1-4 as defined by the WHO Clinical Progression Scale (WHO, Lancet Inf Dis 2020) Exclusion Criteria (all groups): * Known hypersensitivity to any constituent of the investigational medicinal product. * Hepatitis B infection indicated by detectable HBsAg (Hepatitis B surface antigen) in blood. * Detectable antibodies against hepatitis C virus in blood unless active hepatitis C is ruled out by negative HCV-RNA. * HIV infection indicated by detectable HIV antigen and/or HIV antibodies in blood. * Neutrophil count ≤1,000 cells/µl * Hemoglobin ≤10 g/dl * Platelet count ≤100,000 cells/µl * ALT ≥2.0 x ULN * AST ≥2.0 x ULN * Total bilirubin ≥1.5 ULN * eGFR \<60 ml/min/1.73m2 * Pregnancy or lactation. * Any vaccination within 14 days prior to DZIF-10c administration. * Receipt of any SARS-CoV-2 vaccine or SARS-CoV-2 monoclonal antibody in the past. * Diagnosis of bronchial asthma or history of bronchial hyperresponsiveness, COPD, pulmonary fibrosis, or other chronic lung diseases. * Any chronic or clinically significant medical condition that in the opinion of investigator would jeopardize the safety or rights of the volunteer. * History of systemic corticosteroids, immunosuppressive anti-cancer, or other medications considered significant by the trial physician within the last 6 months (a single administration of systemic corticosteroids within ≤6 months and ≥4 weeks of enrollment is acceptable). * Participation in another clinical trial of an investigational medicinal product within the past 12 weeks or expected participation during this study. * Dependency on the principal investigator or study staff; or site personnel directly affiliated with this trial. * Legally incapacitated individuals * Individuals held in an institution by legal or official order * If engaging in sexual activity that could result in pregnancy, inability or unwillingness to comply with the requirements for highly effective contraception