Using Anti-SARS-CoV-2 IgG and IgM Antibodies to Detect Outpatient Cases with Olfactory and Taste Disorders Suspected as Mild Form of COVID-19: a Retrospective Survey

Abstract

Many patients with olfactory disorders were referred during the COVID-19 pandemic in 2020. The aim of this study was to detect outpatient cases with olfactory and taste disorders suspected to mild form of COVID-19 disease in Gorgan city in the north of Iran retrospectively. This study was performed on patients who had the complaints of olfactory disorders during 03/01/2020 to 04/01/2020. They also had the mild symptoms of upper respiratory tract infection. The control group included patients who had similar symptoms during this period but did not report olfactory or taste disturbances. Due to the limitations of serologic kits, this study was performed 2-3 months after the onset of symptoms. The number of patients and controls was 72 and 36 respectively. The range and the mean ± SD of patient's age were 21-63 and 39.82 ± 9.82 years. In both groups, 44.44% were male and 55.56% were female. The time interval between the onset of symptoms and the serologic tests in both groups was 91.11 ± 16.20 days. In the cases and controls, the IgG titer was positive in 44.4% and 22.2% and the IgM titer was positive in 5.6% and 8.3% respectively. IgG antibody titers were higher in cases than in the control group (P = 0.024). There was no correlation among antibody titers and the severity of olfactory disturbances, the gender, and the age. The high COVID-19 IgG antibody titer in patients with olfactory disorder during the pandemic can probably be considered as a warning complaint of COVID-19 and may be used for isolation plans.

Keywords: Anosmia; COVID-19; IgG; IgM; Olfactory; Taste.