Eight-month follow-up of olfactory and gustatory dysfunctions in recovered COVID-19 patients

Abstract

Purpose To investigate the recovery of loss of smell and taste among recovered COVID-19 patients. Materials and methods This cross-sectional follow-up study is a sequel to a study by Biadsee et al. Among the previous study population of 128 non-hospitalized patients, positive for COVID-19 by reverse transcription-polymerase chain reaction (RT-PCR), 97 patients participated in a survey designed for this study. Information and data regarding loss of smell and taste, rate of recovery, xerostomia, and additional symptoms; (Cough, Myalgia, Weakness, Rhinorrhea, Nasal congestion) were collected. Results A total of 43 men and 54 women were included. Mean age was 37.5 years (range 19–74). Mean follow-up was 229 days (range 191–253). Sixty-five patients reported gustatory dysfunction during the disease of which 61.5% reported full recovery, 38.5% partial recovery. Of 65 patients who reported olfactory impairment during the disease, 52% had full recovery and 48% reported partial recovery of olfactory function. Complete recovery of olfactory function was positively associated with full recovery of gustatory function ( p = 0.01). Gender did not significantly affect the recovery of OD and GD ( p = 0.45, p = 0.90, respectively). Patients who experienced olfactory dysfunction as an initial symptom had lower rates of olfactory complete recovery ( p = 0.043). Conclusion After a mean follow-up of 229 days, complete recovery of smell and taste functions occurred in 52% and 61.5%, respectively. However, dysfunction persisted in 48%–38.5% of patients.

Olfactory recovery following infection with COVID-19: A systematic review

“…The remaining 18 studies were conducted in other regions (a pie chart showing distribution is included in the supplementary data provided— S1 Fig ). 10 studies were conducted in Asia: Turkey (n = 5) [ 18 , 27 , 38 , 41 , 50 ], Iran (n = 2) [ 22 , 55 ], India (n = 2) [ 33 , 52 ], Israel (n = 1) [ 32 ]. Four studies were conducted in North America: United States (n = 4), [ 21 , 42 , 48 , 51 ].…”

“…Two studies were conducted in Africa: Egypt (n = 2) [ 34 , 49 ], and two in South America: Brazil (n = 1) [ 53 ], Chile (n = 1) [ 15 , 53 ]. Of the 44 studies, twenty-five (56.8%) reported no funding requirements for the project [ 16 , 18 , 19 , 22 , 27 – 30 , 32 , 33 , 39 , 40 , 42 – 47 , 49 – 51 , 53 , 58 ]; six (13.6%) studies reported funding for the project (sources included academic institutions, government and not-for-profit organizations) [ 15 , 24 , 25 , 31 , 48 , 57 ], and thirteen (29.5%) did not report whether funding was provided [ 17 , 21 , 23 , 26 , 37 , 38 , 52 , 54 – 56 , 58 , 59 ].…”

“…COVID-19 was confirmed by RT-PCR test in all but six studies that either used RT-PCR or serology as a diagnostic tool of COVID-19 [ 25 , 48 , 51 , 54 , 58 , 60 ]. Although most of the patients recruited within studies were not hospitalized due to COVID-19 infection [ 17 , 21 – 26 , 28 , 30 – 32 , 35 , 36 , 41 – 43 , 45 , 47 – 49 , 51 , 54 , 56 , 60 ], some did include patients hospitalized either for monitoring purposes or quarantine [ 18 , 19 , 33 , 52 , 55 , 57 – 59 ]. Twelve studies included a mixture of hospitalized and non hospitalized patients [ 15 , 19 , 20 , 27 , 29 , 34 , 38 – 40 , 46 , 50 , 53 ].…”

Taste Dysfunction and Long COVID-19

“…Indeed, self-reported loss of smell and taste has been observed to be more prognostic than other symptoms including fatigue, fever, or cough in predicting symptomatic infection (Agyeman et al, 2020;Mastrangelo et al, 2021). Significantly, loss of taste is consistently reported as a common symptom of long COVID-19, defined as persistence of symptoms four weeks after infection (Biadsee et al, 2021). Following over four-hundred SARS-CoV-2 infected individuals for severity, improvement, and recovery of subjective chemosensory dysfunction for four months, Schwab et al have reported that the recovery from loss of taste became stagnant after about two months with little improvement subsequently (Schwab et al, 2021).…”

Neurological sequelae of COVID-19: a review

“…2 weeks [ 67 , 68 ] and a minority of patients experiencing OD at 7-month follow-up [ 69 ]. Of interest are the minority of patients whose symptoms persist after several weeks [ 70 , 71 ]. For example, Riestra-Ayora and colleagues noted persistence of OD in 11.2% (14/125) patients at 6-month follow-up [ 72 ] and Nguyen and colleagues noted 24.0% (30/125) 7 months after onset [ 69 ].…”