1. inability to comprehend and to follow all required study procedures 2. allergy or severe reactions to the study drug or smell training 3. pregnant or breastfeeding women 4. pre-existing factors which may account for persistent olfactory dysfunction besides covid-19 (e.g. nasal polyps, obstructive lesions within the nasal cavity, severe anatomical malformations...) 5. received an experimental agent (vaccine, drug, biologic, device, blood product, or medication) within 1 month prior to recruitment in this study or expect to receive an experimental agent during this study. unwilling to refuse participation in another clinical study through the end of this study. 6. have any condition that the investigator believes may interfere with successful completion of the study.

1. inability to comprehend and to follow all required study procedures 2. allergy or severe reactions to the study drug or smell training 3. pregnant or breastfeeding women 4. pre-existing factors which may account for persistent olfactory dysfunction besides covid-19 (e.g. nasal polyps, obstructive lesions within the nasal cavity, severe anatomical malformations...) 5. received an experimental agent (vaccine, drug, biologic, device, blood product, or medication) within 1 month prior to recruitment in this study or expect to receive an experimental agent during this study. unwilling to refuse participation in another clinical study through the end of this study. 6. have any condition that the investigator believes may interfere with successful completion of the study.

inability to comprehend and to follow all required study procedures allergy or severe reactions to the study drug or smell training pregnant or breastfeeding women pre-existing factors which may account for persistent olfactory dysfunction besides covid-19 (e.g. nasal polyps, obstructive lesions within the nasal cavity, severe anatomical malformations…) received an experimental agent (vaccine, drug, biologic, device, blood product, or medication) within 1 month prior to recruitment in this study or expect to receive an experimental agent during this study. unwilling to refuse participation in another clinical study through the end of this study. have any condition that the investigator believes may interfere with successful completion of the study.

inability to comprehend and to follow all required study procedures allergy or severe reactions to the study drug or smell training pregnant or breastfeeding women pre-existing factors which may account for persistent olfactory dysfunction besides covid-19 (e.g. nasal polyps, obstructive lesions within the nasal cavity, severe anatomical malformations…) received an experimental agent (vaccine, drug, biologic, device, blood product, or medication) within 1 month prior to recruitment in this study or expect to receive an experimental agent during this study. unwilling to refuse participation in another clinical study through the end of this study. have any condition that the investigator believes may interfere with successful completion of the study.

1. inability to comprehend and to follow all required study procedures 2. allergy or severe reactions to the study drug or smell training 3. pregnant or breastfeeding women 4. pre-existing factors which may account for persistent olfactory dysfunction besides covid-19 (e.g. nasal polyps, obstructive lesions within the nasal cavity, severe anatomical malformations…) 5. received an experimental agent (vaccine, drug, biologic, device, blood product, or medication) within 1 month prior to recruitment in this study or expect to receive an experimental agent during this study. unwilling to refuse participation in another clinical study through the end of this study. 6. have any condition that the investigator believes may interfere with successful completion of the study.

1. inability to comprehend and to follow all required study procedures 2. allergy or severe reactions to the study drug or smell training 3. pregnant or breastfeeding women 4. pre-existing factors which may account for persistent olfactory dysfunction besides covid-19 (e.g. nasal polyps, obstructive lesions within the nasal cavity, severe anatomical malformations…) 5. received an experimental agent (vaccine, drug, biologic, device, blood product, or medication) within 1 month prior to recruitment in this study or expect to receive an experimental agent during this study. unwilling to refuse participation in another clinical study through the end of this study. 6. have any condition that the investigator believes may interfere with successful completion of the study.