key: cord-0980326-39eiqgxx authors: Kim, So Young; Kim, Dae Woo title: Does the Clinical Spectrum of Coronavirus Disease 2019 (COVID-19) Show Regional Differences? date: 2020-05-08 journal: Clin Exp Otorhinolaryngol DOI: 10.21053/ceo.2020.00612 sha: 5d2567c6aea77c3945552b9b490de51b7d640099 doc_id: 980326 cord_uid: 39eiqgxx nan symptom in European patients, but not in Asian patients [6, 7] . In a multicenter study in Europe, as many as 85.6% and 88.0% of mild-to-moderate COVID-19 patients showed anosmia and dysgeusia [6] . These symptoms preceded other symptoms in 11.8% of patients and were not accompanied by symptoms of nasal obstruction or rhinorrhea [6] . In a single-center study in US, approximately 68% (40/59) and 71% (42/59) of COVID-19 patients reported olfactory disturbance and dysgeusia [8] . Moreover, studies from the United Kingdom have even stated that olfactory dysfunction could be the only symptom of COVID-19 [7, 9] . Thus, abrupt olfactory or gustatory dysfunction might be a clue that a patient has COVID-19. However, findings regarding olfaction seem to be rare in Asian populations. Only 0.93% (2/214) of COVID-19 patients from Wuhan had olfactory disturbance [10] . Although the pathophysiology of these differences remains elusive, there are three plausible explanations. First, it is possible that olfactory disturbance could be underdiagnosed in Asian populations. A study of internet search activities using Google Trends in Europe and the United States demonstrated a strong correlation between the number of COVID-19 patients and searches for olfaction-related information, which led researchers to hypothesize that olfactory disturbance could be a previously unrecognized symptom [11] . Second, it has been suggested that regional differences in the viral spike protein genotypes of SARS-CoV-2 between Asia and Europe could result in differences in viral invasiveness of the olfactory system [12] . Finally, during the last decade, many studies have documented the presence of different endotypes of sinonasal inflammation, such as chronic rhinosinusitis (CRS). Since CRS is characterized by an imbalance between external stimuli and the host response, the possibility of regional differences in the mucosal response to SARS-CoV-2 might be cautiously suggested. COVID-19 is highly infectious and has caused catastrophic impacts on populations throughout the globe. Therefore, early clin- Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding The architecture of SARS-CoV-2 transcriptome Early transmission dynamics in Wuhan, China, of novel coronavirus-infected pneumonia World Health Organization. Coronavirus disease (COVID-19) pandemic [Internet]. Geneva: World Health Organization The clinical manifestations and chest computed tomography findings of coronavirus disease 2019 (COVID-19) patients in China: a proportion meta-analysis Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multicenter European study. Eur Arch Otorhinolaryngol Isolated sudden onset anosmia in CO-VID-19 infection. A novel syndrome? Rhinology Association of chemosensory dysfunction and Covid-19 in patients presenting with influenza-like symptoms. Int Forum Allergy Rhinol Presentation of new onset anosmia during the COVID-19 pandemic Neurologic manifestations of hospitalized patients with coronavirus disease 2019 in Wuhan, China The use of google trends to investigate the loss of smell related searches during COVID-19 outbreak. Int Forum Allergy Rhinol The 2019-new coronavirus epidemic: evidence for virus evolution No potential conflict of interest relevant to this article was reported. So Young Kim https://orcid.org/0000-0002-7361-4930 Dae Woo Kim https://orcid.org/0000-0001-5166-3072