Self-Reported Symptom Study of COVID-19 Chemosensory Dysfunction in Malaysia

Abstract

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 to 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 may be widespread and more common than previously thought among Asians, and manifest as an early symptom of SARS-CoV-2 infection. This has important implications for our understanding of the infectivity of viral strains, diagnosis, and management of this pandemic. Study Registration: NMRR-20-934-54803 and NCT04390165

The D614G Virus Mutation Enhances Anosmia in COVID-19 Patients: Evidence from a Systematic Review and Meta-analysis of Studies from South Asia

“…When anosmia prevalence was determined early during the pandemic in Malaysia (in April 2020), while the D614 virus was still dominant, with only a minor contribution of the G614 virus, the anosmia prevalence was 21.4% . Just 3–5 months later, when the G614 virus dominated, , the anosmia prevalence had increased to 36.6%, consistent with our hypothesis.…”

Smell, taste and chemesthesis disorders in patients with the SARS-CoV-2 Omicron variant in China

“…The questionnaire was adapted from an existing online questionnaires developed by the Global Consortium for Chemosensory Research (GCCR) (Parma et al 2020). The GCCR core questionnaire that implemented in 10 languages as of April 18, 2020 was used or adapted in many other research (Lee et al 2022;Cecchetto et al 2021;Albayay et al 2022). Data collected included the demographic, COVID-19-related characteristics and chemosensory situation before and during infection.…”

“…Information from the World Health Organization (WHO) shows that the number of confirmed COVID-19 cases was 756,411,740 by 16 February, 2023 (https://covid19.who.int). Some reports has shown that chemosensory disorders are important symptoms of COVID-19 infection (Al-Rawi et al 2022;Lee et al 2022;Parma et al 2020). Studies from the United States, Europe, Malaysia and Singapore showed that 12%-88% of COVID-19 infected patients have olfactory and taste disorders (Lechien et al 2020;Menni et al 2020;Lee et al 2022;Tham et al 2021).…”