* participating in another rct in the past 12 months; * presence of comorbidities, which have a contraindication to the use of the study product, not being restricted to: * hiv or htlv virus infection; * chronic hepatitis c (hcv) treated with direct antiviral drugs; * liver failure; * severe renal failure, including dialysis; * present hypersensitivity to the study product (nitazoxanide), as well as to related compounds; * concomitant administration of drugs that may interact with the product under study (nitazoxanide); * participants who underwent treatment with other antiviral drugs; * subject in antineoplastic treatment with chemotherapy or radiation therapy; * subject with severe autoimmune diseases in immunosuppression; * transplanted participants; * pregnant or lactating women; * any other clinical condition that is deemed by the investigator to be an imminent risk to the health and life of the subject.

* participating in another rct in the past 12 months; * presence of comorbidities, which have a contraindication to the use of the study product, not being restricted to: * hiv or htlv virus infection; * chronic hepatitis c (hcv) treated with direct antiviral drugs; * liver failure; * severe renal failure, including dialysis; * present hypersensitivity to the study product (nitazoxanide), as well as to related compounds; * concomitant administration of drugs that may interact with the product under study (nitazoxanide); * participants who underwent treatment with other antiviral drugs; * subject in antineoplastic treatment with chemotherapy or radiation therapy; * subject with severe autoimmune diseases in immunosuppression; * transplanted participants; * pregnant or lactating women; * any other clinical condition that is deemed by the investigator to be an imminent risk to the health and life of the subject.

- participating in another rct in the past 12 months; - presence of comorbidities, which have a contraindication to the use of the study product, not being restricted to: - hiv or htlv virus infection; - chronic hepatitis c (hcv) treated with direct antiviral drugs; - liver failure; - severe renal failure, including dialysis; - present hypersensitivity to the study product (nitazoxanide), as well as to related compounds; - concomitant administration of drugs that may interact with the product under study (nitazoxanide); - participants who underwent treatment with other antiviral drugs; - subject in antineoplastic treatment with chemotherapy or radiation therapy; - subject with severe autoimmune diseases in immunosuppression; - transplanted participants; - pregnant or lactating women; - any other clinical condition that is deemed by the investigator to be an imminent risk to the health and life of the subject.

- participating in another rct in the past 12 months; - presence of comorbidities, which have a contraindication to the use of the study product, not being restricted to: - hiv or htlv virus infection; - chronic hepatitis c (hcv) treated with direct antiviral drugs; - liver failure; - severe renal failure, including dialysis; - present hypersensitivity to the study product (nitazoxanide), as well as to related compounds; - concomitant administration of drugs that may interact with the product under study (nitazoxanide); - participants who underwent treatment with other antiviral drugs; - subject in antineoplastic treatment with chemotherapy or radiation therapy; - subject with severe autoimmune diseases in immunosuppression; - transplanted participants; - pregnant or lactating women; - any other clinical condition that is deemed by the investigator to be an imminent risk to the health and life of the subject.