inclusion criteria: * signed written informed consent taken before any study procedure from any patient capable of giving consent, or, when the patient is incapable of doing so, by his or her legal/authorized representative. * age ≥18 years. at least 30% of participants will be ≥ 65 years old. * first nasopharyngeal swab testing positive for sars-cov-2 by rt-pcr taken no more than 3 days before randomization (visit 1). results of "rapid" semiquantitative tests are not acceptable. * asymptomatic to moderately symptomatic outpatients with no need for immediate hospitalization: grade 1, or grade 2 or grade 3 of clinical severity scale. * no childbearing potential (post-menopause, surgically-induced, or pharmacologically-induced sterility) or, if of childbearing potential, negative urinary pregnancy test (women) and commitment to use at least 2 forms of contraception for at least 168 days from administration of study drug (men and women).

inclusion criteria: * signed written informed consent taken before any study procedure from any patient capable of giving consent, or, when the patient is incapable of doing so, by his or her legal/authorized representative. * age ≥18 years. at least 30% of participants will be ≥ 65 years old. * first nasopharyngeal swab testing positive for sars-cov-2 by rt-pcr taken no more than 3 days before randomization (visit 1). results of "rapid" semiquantitative tests are not acceptable. * asymptomatic to moderately symptomatic outpatients with no need for immediate hospitalization: grade 1, or grade 2 or grade 3 of clinical severity scale. * no childbearing potential (post-menopause, surgically-induced, or pharmacologically-induced sterility) or, if of childbearing potential, negative urinary pregnancy test (women) and commitment to use at least 2 forms of contraception for at least 168 days from administration of study drug (men and women).

inclusion criteria: - signed written informed consent taken before any study procedure from any patient capable of giving consent, or, when the patient is incapable of doing so, by his or her legal/authorized representative. - age ≥18 years. at least 30% of participants will be ≥ 65 years old. - first nasopharyngeal swab testing positive for sars-cov-2 by rt-pcr taken no more than 3 days before randomization (visit 1). results of "rapid" semiquantitative tests are not acceptable. - asymptomatic to moderately symptomatic outpatients with no need for immediate hospitalization: grade 1, or grade 2 or grade 3 of clinical severity scale. - no childbearing potential (post-menopause, surgically-induced, or pharmacologically-induced sterility) or, if of childbearing potential, negative urinary pregnancy test (women) and commitment to use at least 2 forms of contraception for at least 168 days from administration of study drug (men and women).

inclusion criteria: - signed written informed consent taken before any study procedure from any patient capable of giving consent, or, when the patient is incapable of doing so, by his or her legal/authorized representative. - age ≥18 years. at least 30% of participants will be ≥ 65 years old. - first nasopharyngeal swab testing positive for sars-cov-2 by rt-pcr taken no more than 3 days before randomization (visit 1). results of "rapid" semiquantitative tests are not acceptable. - asymptomatic to moderately symptomatic outpatients with no need for immediate hospitalization: grade 1, or grade 2 or grade 3 of clinical severity scale. - no childbearing potential (post-menopause, surgically-induced, or pharmacologically-induced sterility) or, if of childbearing potential, negative urinary pregnancy test (women) and commitment to use at least 2 forms of contraception for at least 168 days from administration of study drug (men and women).