inclusion criteria: * part 1 only: patients hospitalized with a primary diagnosis of covid-19 with or without pneumonia, who are expected to remain in hospital at least seven days after the randomization and who accept continuing to be assessed for the study procedures (home or outpatient unit) up to 6 weeks in case of discharge. part 2 only: patients with a primary diagnosis of covid-19 with or without pneumonia who are not planned to be hospitalized. * patients who prior to developing covid-19 usually have normal bowel habits defined as at least solid-formed 3 stools per week and no more than 3 solid-formed stools per day. * sars-cov-2 rna presence in rectal swab (or stool test) ≤2 days before randomization by local or central lab. * diarrhea defined as at least 3 watery stools in the last 24 hours prior to enrolment

inclusion criteria: * part 1 only: patients hospitalized with a primary diagnosis of covid-19 with or without pneumonia, who are expected to remain in hospital at least seven days after the randomization and who accept continuing to be assessed for the study procedures (home or outpatient unit) up to 6 weeks in case of discharge. part 2 only: patients with a primary diagnosis of covid-19 with or without pneumonia who are not planned to be hospitalized. * patients who prior to developing covid-19 usually have normal bowel habits defined as at least solid-formed 3 stools per week and no more than 3 solid-formed stools per day. * sars-cov-2 rna presence in rectal swab (or stool test) ≤2 days before randomization by local or central lab. * diarrhea defined as at least 3 watery stools in the last 24 hours prior to enrolment

inclusion criteria: - part 1 only: patients hospitalized with a primary diagnosis of covid-19 with or without pneumonia, who are expected to remain in hospital at least seven days after the randomization and who accept continuing to be assessed for the study procedures (home or outpatient unit) up to 6 weeks in case of discharge. part 2 only: patients with a primary diagnosis of covid-19 with or without pneumonia who are not planned to be hospitalized. - patients who prior to developing covid-19 usually have normal bowel habits defined as at least solid-formed 3 stools per week and no more than 3 solid-formed stools per day. - sars-cov-2 rna presence in rectal swab (or stool test) ≤2 days before randomization by local or central lab. - diarrhea defined as at least 3 watery stools in the last 24 hours prior to enrolment

inclusion criteria: - part 1 only: patients hospitalized with a primary diagnosis of covid-19 with or without pneumonia, who are expected to remain in hospital at least seven days after the randomization and who accept continuing to be assessed for the study procedures (home or outpatient unit) up to 6 weeks in case of discharge. part 2 only: patients with a primary diagnosis of covid-19 with or without pneumonia who are not planned to be hospitalized. - patients who prior to developing covid-19 usually have normal bowel habits defined as at least solid-formed 3 stools per week and no more than 3 solid-formed stools per day. - sars-cov-2 rna presence in rectal swab (or stool test) ≤2 days before randomization by local or central lab. - diarrhea defined as at least 3 watery stools in the last 24 hours prior to enrolment