Indian researchers set to study Covid-19 link with loss of smell, taste

India has joined a global scientific consortium to draw a link between Covid-19 and a change or loss of sense of smell or taste – anosmia and dysgeusia – following tests from infected patients and observations of clinicians from various parts of the world since the outbreak of the pandemic.

Four Indian research institutes have collaborated with the Global Consortium of Chemosensory Researchers (GCCR) to collect data via an online survey (http://gcchemosensr.org/) to find the connection between chemical senses and the novel coronavirus. The investigation will determine if anosmia is a reliable ‘early indicator’ of the disease, and when and how the change or loss of sense occurs. The Indian collaborators are also working on a self-assessment test to help monitor change/loss of smell and taste.

Indian collaborators include National Centre for Biological Sciences (NCBS) at the Tata Institute of Fundamental Research (TFIR), Hyderabad, Indraprastha Institute of Information Technology-Delhi, Coimbature-based Karunya Institute of Technology and Sciences, and CSIR- Central Scientific Instruments Organisation.

Researchers said several studies from countries like China, Italy, UK, Belgium, France, Spain and the United States have shown a connection between changes in smell and taste and Covid-19 infection. In April, Harvard researchers in a yet-to-be peer-reviewed study in bioRxiv suggested that the novel coronavirus may be interacting with a certain type of cell inside the olfactory epithelium (tissue inside the nasal cavity) and not the actual neurons involved in processing smell.

Shannon Olsson, who heads the Naturalist-Inspired Chemical Ecology group at the NCBS which is a centre of the TIFR, and is a collaborator, said the rate of occurrence for loss of smell and taste, however, varies widely in these studies, possibly because they used different methods.

“Many other factors affect the senses of smell and taste such as other respiratory illnesses, medicines, lifestyle choices (smoking), genetics, and environment. These also differ within and between countries. Our survey has several questions designed to try and separate these factors,” said Olsson.

She added, “To make the picture even more complicated, there are also genetic variations in Covid-19 viruses themselves in different regions, which could potentially change how they impact smell and taste.”

The India team has translated the questionnaire into Hindi, Tamil, Malayalam, Marathi, Kannada, Gujarati, Punjabi, Bengali, and Urdu, with more languages planned. The objective of the common survey translated in local languages, said collaborators, is to compare the results across borders, find country-specific factors and support policy decisions for India and other countries worldwide.

GCCR comprises over 600 clinicians, neurobiologists, data scientists, cognitive scientists, sensory researchers, and technicians from 50 countries.