Multiple studies have now studied the effects of the SARS-CoV-2 virus impairing several bodily functions that leads to mild to severe symptoms of COVID-19, and increases the chances of fatality in patients already living with underlying conditions such as respiratory problems, diabetes or heart disease.
The loss of sense of smell, medically known as anosmia, is a symptom that is used to identify or diagnose several different conditions ranging from the common cold to blocked sinuses or sinusitis, and other respiratory illnesses or even complex neurological disorders such as Alzheimer's or Parkinson's disease as well.
Based on an early study into this factor which was published in the International Forum of Allergy and Rhinology in April, researchers at the UC San Diego Health studied 1,480 patients with flu-like symptoms that have been identified as the first signs of COVID-19, and found 102 out of the total patients had tested positive for the virus.
The study observed that 59 out of the 102 COVID-19 positive patients reported smell and taste loss, making it a 68% and 71% rate of the symptoms respectively. From 203 out of the remaining 1,378 patients who tested negative, there was a low 16% and 17% presence of the symptoms. The study also went on to add that "smell and taste impairment were independently and strongly associated with COVID‐19 positivity".
Another study done in Europe among patients with mild to moderate symptoms of COVID-19 found as many as 86% of the people reporting a reduced sense of smell and a similarly high percentage of people also experienced a reduction in their sense of taste, also known as ageusia. According to experts, problems with the sense of smell have been more evident among younger patients and women.
Some doctors also perceive the loss of these senses could be intertwined, as they are even during the onset of a common cold, but they think the loss of sense of taste could also be a direct result due to the new coronavirus infection.
Scientific journal Nature conducted a large survey using an app-based symptom tracker in the United Kingdom and the United States, two of the worst-hit countries during the COVID-19 pandemic. Out of the UK cohort of 6,452 people who had tested positive for COVID-19, almost 65% of the patients reported a loss of smell and taste as symptoms. Another 20% of the participants of the study who returned negative tests for COVID-19 also reported a loss of smell and taste.
Despite featuring prominently in several studies, the World Health Organization has listed loss of sense of smell and taste among the less common symptoms of COVID-19.
The emergence of the loss of olfactory senses, however, has thrown light on a way to detect COVID-19 earlier in patients as anosmia and ageusia have been known to set in in the first three days of someone being infected with the virus.