Malaysian COVID-19 Anosmia Study (Phase 1) - A Nationwide Multicentre Cross-Sectional Study
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ClinicalTrials.gov Identifier: NCT04390165 |
Recruitment Status :
Completed
First Posted : May 15, 2020
Last Update Posted : February 25, 2021
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The Malaysian COVID-19 Anosmia Study is a nationwide multicentre observational study to investigate the prevalence and characteristics of olfactory and gustatory/taste disturbances in COVID-19 infection in Malaysia, and to evaluate the predictive value of screening for these symptoms in COVID-19 infection.
This study consists of two phases: the first phase is a cross-sectional study and the second phase is a case-control study. The cross-sectional study is described here (the case-control study is described in a separate ClinicalTrials.gov record).
Condition or disease | Intervention/treatment |
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SARS-CoV Infection COVID-19 Anosmia Dysgeusia | Other: Patient-Reported Online Questionnaire on Olfactory & Taste Disturbances |
The world is currently in the midst of the Coronavirus 2019 (COVID-19) pandemic that is caused by a novel coronavirus, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). According to published cohort studies on COVID-19 infected patients, the most prevalent symptoms consist of fever, dry cough, dyspnoea, sputum production, myalgia, arthralgia, headache, diarrhoea, and sore throat. Recently, there have been concerns of significant viral transmission through asymptomatic, pre-symptomatic or even mildly symptomatic patients.
There is increasing anecdotal evidence from patients and healthcare professionals highlighting isolated loss of sense of smell (anosmia) and taste disturbances (dysgeusia) as atypical symptoms of COVID-19 infection in otherwise asymptomatic patients. In parallel, expert statements from the British Association of Otorhinolaryngology-Head & Neck Surgery (ENT UK), British Rhinological Society, and the American Association of Otolaryngology-Head & Neck Surgery (AAO-HNS) have suggested that olfactory and taste disturbances could be a clinical feature of COVID-19 infection.
Rapidly emerging evidence from Europe, the United Kingdom and the United States have found olfactory and taste disturbances to be highly prevalent in patients diagnosed with COVID-19. In contrast, there is currently limited evidence from Asia on the prevalence of these symptoms in COVID-19 infection.
The aim of this cross-sectional study is to study the prevalence and characteristics of olfactory and taste disturbance in patients with COVID-19 infection in Malaysia. COVID-19 positive patients will be recruited from participating Malaysian Ministry of Health-designated COVID-19 treating hospitals across the country. Participants will answer an online questionnaire to evaluate and characterise these symptoms.
Study Type : | Observational |
Actual Enrollment : | 498 participants |
Observational Model: | Case-Only |
Time Perspective: | Cross-Sectional |
Official Title: | Olfactory and Gustatory Disturbances as a Clinical Presentation of Coronavirus Disease 2019 (COVID-19) Infection in Malaysia - A Nationwide Multicentre Cross-Sectional Study |
Actual Study Start Date : | June 6, 2020 |
Actual Primary Completion Date : | November 30, 2020 |
Actual Study Completion Date : | November 30, 2020 |

Group/Cohort | Intervention/treatment |
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Malaysian COVID-19 Cohort
A cohort of COVID-19 positive patients will be recruited from participating Malaysian Ministry of Health-designated COVID-19 treating hospitals across the country.
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Other: Patient-Reported Online Questionnaire on Olfactory & Taste Disturbances
This is an online patient-reported questionnaire that examines the presence or absence of olfactory and taste disturbances, the onset of olfactory and taste disturbances in relation to other COVID-19 symptoms, and the temporal evolution of the severity of olfactory and taste disturbances. The occurrence of ear symptoms in COVID-19 infection will also be evaluated in this questionnaire as a secondary outcome. The questionnaire will also have questions relating to the patient's underlying health conditions, risk factors for COVID-19 infection, and demographics. |
- Presence or absence of olfactory and taste disturbances in COVID-19 patients [ Time Frame: Within 2 weeks preceding the diagnosis of COVID-19 infection ]In the patient-reported online questionnaire, subjects will be asked regarding whether they experienced symptoms of olfactory and/or taste disturbances
- Prevalence of olfactory disturbances in COVID-19 patients [ Time Frame: Within 2 weeks preceding the diagnosis of COVID-19 infection ]Percentage of COVID-19 patients experiencing olfactory disturbances (anosmia or hyposmia)
- Prevalence of taste disturbances in COVID-19 patients [ Time Frame: Within 2 weeks preceding the diagnosis of COVID-19 infection ]Percentage of COVID-19 patients experiencing taste disturbances
- Clinical manifestations of study participants [ Time Frame: Within 2 weeks preceding the diagnosis of COVID-19 infection ]In the patient-reported online questionnaire, subjects will be asked regarding other symptoms they experienced when they were diagnosed with COVID-19 (e.g. headache, nasal congestion, fever, chills, cough, dyspnoea, gastrointestinal symptoms, eye & ear symptoms)
- Other pre-existing health conditions [ Time Frame: Prior to diagnosis of COVID-19 infection ]In the patient-reported online questionnaire, subjects will be asked regarding their pre-existing health conditions (for example, obesity, diabetes, hypertension, cardiac conditions, previous head trauma, chronic rhinosinusitis, etc.)
- Rating of baseline sense of smell & taste in COVID-19 patients prior to diagnosis of their infection [ Time Frame: Prior to 2 weeks preceding the diagnosis of COVID-19 infection (Baseline) ]In the patient-reported online questionnaire, subjects will be asked to rate their sense of smell and taste before their diagnosis of COVID-19 infection
- Rating of sense of smell & taste in COVID-19 patients at time of diagnosis of their infection [ Time Frame: Within 2 weeks preceding the diagnosis of COVID-19 infection ]In the patient-reported online questionnaire, subjects will be asked to rate their sense of smell and taste at the time of diagnosis of COVID-19 infection
- Rating of sense of smell & taste in COVID-19 patients at time of answering questionnaire survey [ Time Frame: Up to 6 months ]In the patient-reported online questionnaire, subjects will be asked to rate their sense of smell and taste at the time of answering questionnaire survey

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Sampling Method: | Probability Sample |
The study population are adult patients with laboratory-confirmed COVID-19 infection from participating Malaysian hospital sites in this study, since the arrival of COVID-19 infection in Malaysia (January 2020) until present time.
These patients comprise those who either currently inpatient or already discharged into the community. For patients already discharged into the community, they will be invited to participate by phone call from the hospital treating team. Once verbal consent has been obtained, they a QR code or internet URL link to the online questionnaire website will be sent to these patients.
Inclusion Criteria:
- Age at least 18 years old
- Laboratory confirmed COVID-19 infection [Reverse Transcription Polymerase Chain Reaction (RT-PCR)]
- Patients clinically able to answer the questionnaire
Exclusion Criteria:
- Patients with olfactory or taste/gustatory disorders before the COVID-19 epidemic
- Patients without a laboratory-confirmed COVID-19 diagnosis
- Patients in intensive care unit at the time of study

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04390165
Malaysia | |
Hospital Enche' Besar Hajjah Khalsom | |
Kluang, Johor, Malaysia, 86000 | |
Hospital Sultanah Bahiyah | |
Alor Setar, Kedah, Malaysia, 05400 | |
Hospital Raja Perempuan Zainab II | |
Kota Bharu, Kelantan, Malaysia, 15200 | |
Hospital Tuanku Jaafar | |
Seremban, Negeri Sembilan, Malaysia, 70300 | |
Hospital Tengku Ampuan Afzan | |
Kuantan, Pahang, Malaysia, 25100 | |
Penang Hospital | |
George Town, Penang, Malaysia, 10990 | |
Hospital Raja Permaisuri Bainun | |
Ipoh, Perak, Malaysia, 30450 | |
Hospital Tuanku Fauziah | |
Kangar, Perlis, Malaysia, 01000 | |
Hospital Queen Elizabeth | |
Kota Kinabalu, Sabah, Malaysia, 88200 | |
Sarawak General Hospital | |
Kuching, Sarawak, Malaysia, 93586 | |
Hospital Sungai Buloh | |
Sungai Buloh, Selangor, Malaysia, 47000 | |
Hospital Sultanah Nur Zahirah | |
Kuala Terengganu, Terengganu, Malaysia, 20400 | |
Kuala Lumpur General Hospital | |
Kuala Lumpur, Malaysia, 50586 | |
Hospital Melaka | |
Melaka, Malaysia, 75400 |
Study Chair: | Siti Sabzah Mohd Hashim, MD MS | Hospital Sultanah Bahiyah |
Publications:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Siti Sabzah bt Mohd Hashim, MD, MS (ORL-HNS), Head of Otorhinolaryngology Service, Ministry of Health, Malaysia & Senior Consultant Otorhinolaryngologist, Hospital Sultanah Bahiyah |
ClinicalTrials.gov Identifier: | NCT04390165 |
Other Study ID Numbers: |
MCO-001 NMRR-20-934-54803 ( Other Identifier: National Medical Research Register (NMRR), Malaysia ) |
First Posted: | May 15, 2020 Key Record Dates |
Last Update Posted: | February 25, 2021 |
Last Verified: | February 2021 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
Cross-sectional study Prevalence Otorhinolaryngology Infectious Diseases Anosmia Dysgeusia |
Olfactory Disorders Taste Disorders COVID-19 SARS-CoV-2 Coronavirus 2019 |
Infections COVID-19 Severe Acute Respiratory Syndrome Anosmia Dysgeusia Respiratory Tract Infections Pneumonia, Viral Pneumonia Virus Diseases Coronavirus Infections |
Coronaviridae Infections Nidovirales Infections RNA Virus Infections Lung Diseases Respiratory Tract Diseases Olfaction Disorders Sensation Disorders Neurologic Manifestations Nervous System Diseases Taste Disorders |