- allergy to "iodine," shellfish, or food dye - receiving intranasal steroids - sinus surgery within 30 days of beginning the study - intubated at the time of enrollment - pregnancy - participation in other covid-19 studies - to be determined on a case by case basis

- allergy to "iodine," shellfish, or food dye - receiving intranasal steroids - sinus surgery within 30 days of beginning the study - intubated at the time of enrollment - pregnancy - participation in other covid-19 studies - to be determined on a case by case basis