To the range of symptoms attached to COVID-19, scientists are now considering “loss of smell''. A new survey by Bengaluru-based and international scientists is underway to analyse the connection between the chemical senses and the disease.
According to existing clinical data, significant numbers of patients positive for COVID-19 have developed anosmia (total loss of smell) or hyposmia (decreased loss of smell). In Germany, a reported two in three confirmed cases have anosmia. In South Korea, 30% of positive cases have had anosmia as a major symptom in otherwise mild cases.
However, Associate Professor Sharon Olsson of the National Centre for Biological Sciences (NCBS) in Bengaluru who is attached to the survey project, told DH that these tests had resulted in wildly divergent findings.
“The rate of occurrence for loss of smell and taste varies widely in these studies, possibly because they used different methods. In addition, there are many factors that can affect smell and taste such as other diseases, medicine-use, lifestyle, genetics, and environment, and these will also differ within and between countries. To make the picture even more complicated, there are also genetic variations in the COVID-19 viruses themselves in different regions, which could potentially change how they impact smell and taste,” she explained.
Dr Olsson added that with the survey, scientists hope to determine if loss or change of smell or taste is a reliable symptom to indicate infection. “Plus, when and how the change or loss of sense occurs,” she added, clarifying that the survey will conclude once the data reaches a set statistical threshold.
For India, the survey has been translated into more than 20 regional languages, including Kannada, Hindi, Tamil, Malayalam, Marathi, Gujarati, Punjabi, Bengali, and Urdu.
Some of the questions in the survey, which are open to confirmed or suspect COVID-19 cases, will attempt to gauge the poll takers’ sense of smell, before, during and after recovering from the infection, and whether they have pre-existing medical conditions etc.
The survey, which is being operated by the Global Consortium of Chemosensory Researchers (GCCR), will see India-based scientists joining more than 600 clinicians, neurobiologists, data scientists, cognitive scientists, sensory researchers, and technicians from 50 countries to collect and analyse the data.
Researchers from the Tata Institute of Fundamental Research (Hyderabad), Indraprastha Institute of Information Technology (IIIT-Delhi), Karunya Institute of Technology and Sciences, and the Council of Scientific and Industrial Research (CSIR)-Central Scientific Instruments Organisation (CSIO) are also part of the project.
Post-viral anosmia
Post-viral anosmia is one of the leading causes of loss of sense of smell in adults, accounting for up to 40% cases of anosmia. Over 200 different viruses, including some strains of coronavirus, are known to cause upper respiratory tract infections, which affect the sense of smell.
The survey is available here: http://gcchemosensr.org/