inclusion criteria: * ≥ 18 years old, males and females * signed and dated written informed consent in accordance with international council on harmonisation - good clinical practice (ich-gcp) and local legislation prior to admission to the trial * asymptomatic for coronavirus disease 2019 (covid-19) at time of screening and at randomization * household contact with exposure to an individual with a diagnosis of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection (i.e. exposure to the index case) * randomization within 96 hours of collection of the index cases' positive sars-cov-2 diagnostic test sample (nucleic acid or antigen-based) from any respiratory tract specimen (e.g. oropharyngeal, nasopharyngeal (np), or nasal swab, or saliva); based on test sample collection date, not the result date. * from screening and randomization, the trial participant anticipates living in the same household with the index case until protocol day 29. * women of childbearing potential (wocbp)\* and men able to father a child must be ready and able to use highly effective methods of birth control per international council on harmonisation (ich) m3 (r2) that result in a low failure rate of less than 1% per year when used consistently and correctly. * a woman is considered of childbearing potential (wocbp), i.e. fertile, following menarche and until becoming post-menopausal unless permanently sterile. permanent sterilisation methods include hysterectomy, bilateral salpingectomy and bilateral oophorectomy. tubal ligation is not a method of permanent sterilisation. a postmenopausal state is defined as no menses for 24 months without an alternative medical cause.

inclusion criteria: * ≥ 18 years old, males and females * signed and dated written informed consent in accordance with international council on harmonisation - good clinical practice (ich-gcp) and local legislation prior to admission to the trial * asymptomatic for coronavirus disease 2019 (covid-19) at time of screening and at randomization * household contact with exposure to an individual with a diagnosis of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection (i.e. exposure to the index case) * randomization within 96 hours of collection of the index cases' positive sars-cov-2 diagnostic test sample (nucleic acid or antigen-based) from any respiratory tract specimen (e.g. oropharyngeal, nasopharyngeal (np), or nasal swab, or saliva); based on test sample collection date, not the result date. * from screening and randomization, the trial participant anticipates living in the same household with the index case until protocol day 29. * women of childbearing potential (wocbp)\* and men able to father a child must be ready and able to use highly effective methods of birth control per international council on harmonisation (ich) m3 (r2) that result in a low failure rate of less than 1% per year when used consistently and correctly. * a woman is considered of childbearing potential (wocbp), i.e. fertile, following menarche and until becoming post-menopausal unless permanently sterile. permanent sterilisation methods include hysterectomy, bilateral salpingectomy and bilateral oophorectomy. tubal ligation is not a method of permanent sterilisation. a postmenopausal state is defined as no menses for 24 months without an alternative medical cause.

inclusion criteria: - ≥ 18 years old, males and females - signed and dated written informed consent in accordance with international council on harmonisation - good clinical practice (ich-gcp) and local legislation prior to admission to the trial - asymptomatic for coronavirus disease 2019 (covid-19) at time of screening and at randomization - household contact with exposure to an individual with a diagnosis of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection (i.e. exposure to the index case) - randomization within 96 hours of collection of the index cases' positive sars-cov-2 diagnostic test sample (nucleic acid or antigen-based) from any respiratory tract specimen (e.g. oropharyngeal, nasopharyngeal (np), or nasal swab, or saliva); based on test sample collection date, not the result date. - from screening and randomization, the trial participant anticipates living in the same household with the index case until protocol day 29. - women of childbearing potential (wocbp)* and men able to father a child must be ready and able to use highly effective methods of birth control per international council on harmonisation (ich) m3 (r2) that result in a low failure rate of less than 1% per year when used consistently and correctly. - a woman is considered of childbearing potential (wocbp), i.e. fertile, following menarche and until becoming post-menopausal unless permanently sterile. permanent sterilisation methods include hysterectomy, bilateral salpingectomy and bilateral oophorectomy. tubal ligation is not a method of permanent sterilisation. a postmenopausal state is defined as no menses for 24 months without an alternative medical cause.

inclusion criteria: - ≥ 18 years old, males and females - signed and dated written informed consent in accordance with international council on harmonisation - good clinical practice (ich-gcp) and local legislation prior to admission to the trial - asymptomatic for coronavirus disease 2019 (covid-19) at time of screening and at randomization - household contact with exposure to an individual with a diagnosis of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection (i.e. exposure to the index case) - randomization within 96 hours of collection of the index cases' positive sars-cov-2 diagnostic test sample (nucleic acid or antigen-based) from any respiratory tract specimen (e.g. oropharyngeal, nasopharyngeal (np), or nasal swab, or saliva); based on test sample collection date, not the result date. - from screening and randomization, the trial participant anticipates living in the same household with the index case until protocol day 29. - women of childbearing potential (wocbp)* and men able to father a child must be ready and able to use highly effective methods of birth control per international council on harmonisation (ich) m3 (r2) that result in a low failure rate of less than 1% per year when used consistently and correctly. - a woman is considered of childbearing potential (wocbp), i.e. fertile, following menarche and until becoming post-menopausal unless permanently sterile. permanent sterilisation methods include hysterectomy, bilateral salpingectomy and bilateral oophorectomy. tubal ligation is not a method of permanent sterilisation. a postmenopausal state is defined as no menses for 24 months without an alternative medical cause.