The Flavor test has been developed and validated by our group to assess retro-nasal olfactory performances.

The original flavor test has been simplified, with the great advantage to be self-administrable for COVID-19 patients in isolation, without any risk to health professionals.

Smell and taste dysfunctions (STDs) are symptoms associated with COVID-19 syndrome, even if their incidence is still uncertain and variable. In this study, the effects of SARS-CoV-2 infection on chemosensory function have been investigated using both a self-reporting questionnaire on smell and flavor perception, and a simplified flavor test. A total of 111 subjects (19 hospitalized [HOS] and 37 home-isolated [HI] COVID-19 patients, and 55 healthy controls [CTRL]) were enrolled in the study. The flavor test used consists in the self-administration of four solution with a pure olfactory stimulus (coffee), a mixed olfactory-trigeminal stimulus (peppermint), and a complex chemical mixture (banana).

After SARS-CoV-2 infection, HOS and HI patients reported similar frequency of STDs, with a significant reduction of both smell and flavor self-estimated perception.

The aromas of the Flavor test were recognized by HI and HOS COVID-19 patients similarly to CTRL, however the intensity of the perceived aromas was significantly lower in patients compared to controls.

This suggests that a chemosensory impairment is present after SARS-CoV-2 infection, and the modified "flavor test" could be a novel self-administering objective screening test to assess STDs in COVID-19 patients.

Inclusion Criteria:

• Adults (≥18 years of age) that gave their written informed consent to the study
• Diagnosis of COVID-19 was confirmed by PCR of nasopharyngeal swab (HI or HOS)
• Negative COVID-19 nasopharyngeal swab (CTRL)
• Subjects with no critical conditions and able to understand the protocol

Exclusion Criteria:

• nasal obstruction or previous nasal diseases

A total of 111 subjects (19 hospitalized [HOS] and 37 home-isolated [HI] COVID-19 patients, and 55 healthy controls [CTRL]) were enrolled in the study. The mean age for overall population was 41.52±14.45 years.