Self-reported symptom study of COVID-19 chemosensory dysfunction in Malaysia
Authors: Lee Shen-Han , Yeoh Zhi Xiang , Sachlin Ida Sadja’ah , Gazali Norzi , Soelar Shahrul Aiman , Foo Chee Yoong , Low Lee Lee , Syed Alwi Sharifah Baizura , Tengku Kamalden Tengku Mohamed Izam , Shanmuganathan Jothi , Zaid Masliza , Wong Chun Yiing , Chua Hock Hin , Yusuf Suhaimi , Muhamad Dzawani , Devesahayam Philip Rajan , Ker Hong Bee , Salahuddin Zulkiflee , Mustafa Mahiran , Sawali Halimuddin , Lee Heng Gee , Din Sobani , Misnan Nor Arisah , Mohamad Amran , Ismail Mohd Noor , Periasamy Chenthilnathan , Chow Ting Soo , Krishnan Elang Kumaran , Leong Chee Loon , Lim Linda Pei Fang , Zaidan Nor Zaila , Ibrahim Mohd Zambri , Abd Wahab Suhaila , Mohd Hashim Siti Sabzah ,   Malaysian COVID-19 Anosmia Research Group, Bachok Nurul Asyikin , Sim Linger , Ti Tiana , Lee Teng Huei , Mohd Nor Siti Nurul Aliaa , Tay Kim Siang , Gouri Pagan Abirami , Aman Anura , Mohamed Awang Kamariah , Salleh Jamal Nasser , Manickam Harridas , Mohamad Zaki Nursyamimi , Moh Cheng Keat , Thurairaju Ruthran , Yee Ho Hwee , Abd Aziz Nabilah , Ramli Rosdi , Mohd Noor Rosli , Mat Jelani Anilawati , Alimi Mustapha Mohd Fakri , Ab Aziry Abdul Aziez , Lohanadan Kribananthan , Abdul Razak Siti Farhana , Saw Yen Tsen , Kong Jason Henn Leong , Teh Carren Sui Lin , Prem Singh Kuldip Kaur , Karunakaran Arvindan , Rajendram Nesha , Nik Mohd Nik Khairani , Ja’afar Nurul Amilin , Che Mohd Razali Siti Sarah , Baskaran Shamesh , Hassan Farrah Hani , Thuraisingam Kalaiselvi , Hithayathullah Hanisah , Manjeet Singh Prempreet Kaur , Lee Shen-Han , Zainul Nadiah Hanim , Ooi Man Chek , Mahadzir Siti Aishah , Mohd Yusoff Nurul Afifah , Mohamad Illiayas Anees Fatimah , Tan Yi Shan , Ismail Ibtisam , Chan Huan Keat , Saniasiaya Jeyasakthy , Ng Tiang Koi , Ramasamy Kuganathan , Mohd Saifuddin Fatin Farha 
Published: February 2022

Alterations in the three chemosensory modalities—smell, taste, and chemesthesis—have been implicated in Coronavirus Disease 2019 (COVID-19), yet emerging data suggest a wide geographic and ethnic variation in the prevalence of these symptoms. Studies on chemosensory disorders in COVID-19 have predominantly focused on Caucasian populations whereas Asians remain understudied. We conducted a nationwide, multicentre cross-sectional study using an online questionnaire on a cohort of RT-PCR-confirmed adult COVID-19 patients in Malaysia between 6 June and 30 November 2020. The aim of our study was to investigate their presenting symptoms and assess their chemosensory function using self-ratings of perceived smell, taste, chemesthesis, and nasal blockage. In this cohort of 498 patients, 41.4% reported smell and/or taste loss when diagnosed with COVID-19, which was the commonest symptom. Blocked nose, loss of appetite, and gastrointestinal disturbances were independent predictors of smell and/or taste loss on multivariate analysis. Self-ratings of chemosensory function revealed a reduction in smell, taste, and chemesthesis across the entire cohort of patients that was more profound among those reporting smell and/or taste loss as their presenting symptom. Perceived nasal obstruction accounted for only a small proportion of changes in smell and taste, but not for chemesthesis, supporting viral disruption of sensorineural mechanisms as the dominant aetiology of chemosensory dysfunction. Our study suggests that chemosensory dysfunction in COVID-19 is more widespread than previously reported among Asians and may be related to the infectivity of viral strains.

Study Registration: NMRR-20-934-54803 and NCT04390165.