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Clinical Trial
. 2022 Aug;191(4):1759-1766.
doi: 10.1007/s11845-021-02786-x. Epub 2021 Sep 25.

Quantitative but not qualitative flavor recognition impairments in COVID-19 patients

Immacolata Cristina Nettore #  1 , Elena Cantone #  2 , Giuseppe Palatucci  1 , Fabiana Franchini  1 , Rufina Maturi  1 , Mariagiovanna Nerilli  3 , Elio Manzillo  3 , Maria Foggia  1 , Luigi Maione  1 , Paola Ungaro  4 , Annamaria Colao  1 , Paolo Emidio Macchia  5
Affiliations
Clinical Trial

Quantitative but not qualitative flavor recognition impairments in COVID-19 patients

Immacolata Cristina Nettore et al. Ir J Med Sci. 2022 Aug.

Abstract

Background: Smell and taste dysfunctions (STDs) are symptoms associated with COVID-19 syndrome, even if their incidence is still uncertain and variable.

Aims: 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.

Methods: 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. They received a self-evaluation questionnaire and a self-administered flavor test kit. The flavor test used consists in the self-administration of four solutions with a pure olfactory stimulus (coffee), a mixed olfactory-trigeminal stimulus (peppermint), and a complex chemical mixture (banana).

Results: After SARS-CoV-2 infection, HOS and HI patients reported similar prevalence 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.

Conclusion: Data reported here 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.

Clinical trial registration no: NCT04840966; April 12, 2021, retrospectively registered.

Keywords: COVID-19; Flavor; Flavor test; Hyposmia; Retro-nasal olfaction; Smell.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Quantitative self-estimated effect of SARS-CoV-2 infection on smell (A) and flavor (B). Chemosensory function was investigated asking the patients to score on a 1–10 scale their ability to recognize smell and flavors before (pre) and after (post) the infection. Median scores and IQR are shown. No differences across the HOS and HI groups were detected using the two-way ANOVA test. HOS hospitalized COVID-19, HI home-isolated COVID-19. ***p < 0.0001
Fig. 2
Fig. 2
Perceived intensity of the tested aromas (A banana, B coffee, C peppermint, D water). Median scores and IQR are shown. CTRL healthy controls, HOS hospitalized COVID-19, HI home-isolated COVID-19 patients, ns not significant; *p < 0.05, **p < 0.01, ***p < 0.001
Fig. 3
Fig. 3
Correlation between self-estimated smell (A and B) and flavor (C and D) perception with number of properly recognized aromas (A and C) and average perceived intensity for the tested aromas (B and D). All correlations are significant. The analyses for each single aroma are shown in figs. S1 and  S2
See this image and copyright information in PMC

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