SARS-CoV-2 Virologic and Immunologic Correlates in Patients with Olfactory and Taste Disorders

Abstract

The main object of the study was to investigate the SARS-CoV-2 molecular and serological pattern in patients with mild symptoms including anosmia and ageusia. A cohort of 69 patients with olfactory and taste disorders (OTDs) were enrolled and prospectively monitored. Serological and molecular assays for the characterization of SARS-CoV-2 IgG and SARS-CoV-2 RNA, respectively, were performed at the time of enrolment and after 7 and 14 days. Patients were stratified according to the symptoms' onset. A total of 52 patients (75.4%) were diagnosed as COVID-19 positive being SARS-CoV-2 RNA and/or SARS-CoV-2 IgG positive. The remaining 17 (24.6%) were negative for COVID-19 and excluded from the analysis. We reported that only 34 out of 52 patients (65.4%) were positive for SARS-CoV-2 RNA. Moreover, the median time from onset of symptoms and enrolment was significantly higher in those patients with negative SARS-CoV-2 RNA in nasal swabs, suggesting that symptoms might last longer than SARS-CoV-2 replication. The great majority of patients (80%) developed SARS-CoV-2 IgG at three weeks after symptoms' onset while the detectability of SARS-CoV-2 RNA dramatically decreased over time, suggesting the crucial role of combination of molecular and serological assays for the diagnosis of COVID-19 in those patients reporting mild symptoms.

Keywords: SARS-CoV-2; ageusia; anosmia; serology.

Figure 1

Olfactory and taste disorder severity at T0, T7 and T14 scored according to HSR (A) and a questionnaire based on CiTAS (B) in COVID-19 positive patients. All the relevant statistics values are reported in the corresponding tables.

Figure 2

Prevalence and kinetics of SARS-CoV-2 RNA and SARS-CoV-2 IgG positive patients in a cohort of 52 COVID-19 positive anosmic and aguesic patients since symptoms’ onset. Prevalence of SARS-CoV-2 RNA positive patients (dark gray bars) and SARS-CoV-2 IgG positive patients (white bars) was evaluated according to days after symptoms’ onset. Percentage of positive patients was given for each bar (A). Median SARS-CoV-2 IgG titer (B) and SARS-CoV-2 SARS-CoV-2 RNA (C) were evaluated during the follow-up. P-values for significant comparison were given for each graph. n.a: not available (not positive results reported).