Taste alteration in COVID-19: a rapid review with data synthesis reveals significant geographical differences

Abstract

To facilitate a timely understanding of the differences in the prevalence of gustatory disturbances (GD) in individuals infected with SARS-CoV-2, we undertook a rapid systematic review of articles published in the repository of the National Library of Medicine (MEDLINE/PubMed) and medRxiv from their inception until September 3, 2020. The minimum requirements for completing a restricted systematic review were met. Of the 431 articles retrieved, 61 eligible studies (28,374 confirmed COVID-19 cases) from 20 countries were included in the analysis. The results show strong significant differences in the overall reported prevalence of GD between East Asia [13%, 95% CI 0.14-26.06%], Middle East [38.83%, 95% CI 27.47-50.19%], Europe [57.18%, 95% CI 52.35-62.01%], and The Americas [66.78%, 95% CI 54.77-78.79%]. There were no trends showing differences of prevalence of GD in the available literature between February and August,, 2020. These data show that there is a distinct geographical distribution of GD in COVID-19 patients and this may explain the differences of diagnostic criteria for COVID-19 case definition.

Self-reported smell and taste alteration as the sole clinical manifestation of SARS-CoV-2 infection

“…In the systematic reviews analyzing smell and/or taste together, the range was 5.6-94%. The heterogeneity of these findings may be partially due to differences in the geographical distribution of this association 3 . Interestingly, when the prevalence was pooled on the total number of cases examined, olfactory and gustatory alterations were found in approximately half of COVID-19 patients.…”

“…In agreement with the growing body of evidence, sudden onset of anosmia, ageusia or dysgeusia have now been recognized as major clinical characteristics of the disease and have been included in the list of key clinical criteria for case definition of COVID-19 by the European Centre for Disease Prevention and Control as well as other Public Health surveillance organizations across the world such as CDC, WHO 3 , and Public Health England 7 . However, it is not known whether concurrent olfactory and gustatory alterations may indeed represent the only clinical sign of SARS-CoV-2 infection in otherwise healthy patients.…”

“…cough, fever, and fatigue, according to a recent meta-analysis 2 ) have been used as cardinal clinical diagnostic criteria since the beginning of the outbreak, new olfactory and taste disorder(s) were not initially linked to SARS-CoV-2 infection and have not been used for case identification and testing prioritization by the US Centers for Disease Control and Prevention (CDC) or World Health Organization (WHO) until August 2020. 3 The first systematic assessments of the evidence available up to March 2020 failed to identify associations between anosmia/ageusia and COVID-19 4,5 . For example, none of the studies included in an early systematic review reported about olfactory or gustative dysfunctions 4 .…”

Estimating the prevalence of oral manifestations in COVID-19 patients: a systematic review

“…Professor C. Hopkins, President of the British Rhinological Society, has noted that the loss of smell or taste may be the sole symptom of COVID-19 [ 91 ]. Several public health surveillance organizations, including the European Centre for Disease Prevention and Control, the Centers for Disease Control and Prevention, the WHO [ 92 ], and Public Health England, have incorporated the sudden onset of anosmia, ageusia, or dysgeusia into their primary clinical criteria for defining a COVID-19 case [ 93 ]. The present systematic review also found that general symptoms typically follow oral symptoms, particularly the loss of taste.…”

Prognostic Value of Anosmia in SARS-COV-2: A Case Control Study

“…Novel coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an outbreak that emerged in China in December 2019, has rapidly evolved into a global pandemic and has become a persistent global health threat. Sudden onset of anosmia, ageusia, or dysgeusia has now been recognized as a major clinical characteristic of the disease and has been included in the list of key clinical criteria for case definition of COVID-19 by the European Centre for Disease Prevention and Control as well as other public health surveillance organizations across the world, such as the CDC, the WHO 1 and Public Health England 2 .…”