New evidence finds that anosmia- loss of smell as a new symptom caused by the COVID-19 virus. Experts believe that it can be added as a potential screening tool for the novel viral infection, and here’s why!
Cases of post-viral anosmia are one of the leading causes of loss of smell among adults suffering from viral infection. This has been associated with previous coronaviruses which are usually known to cause upper respiratory tract infections and have accounted for 10-15% of the cases. Therefore it comes off as no surprise that the current novel COV ID-19 virus also causes anosmia in the infected.
A significant number of cases from South Korea, Italy, and China prove as good evidence for COVID-19 patients developing anosmia. More than 2 out of 3 confirmed cases in Europe have been diagnosed with anosmia. It is also noticed that several COVID-19 cases also present anosmia as the only symptom. Given the above evidence, experts contemplate using anosmia of a screening tool to diagnose people with COVID-19 at the early stages.
Cases of anosmia reflect how COVID-19 affects the brain:
“There’s something unusual about the relationship between COVID-19 and smell,” states Sandeep Robert Datta a neuroscientist from Harvard Medical School and one of the leading scientists in the study. It is well known that common cold, is associated with stuffy noses leading to a temporary loss of smell, but it found that the COVID-19 virus leaves the nose free. “But recently lots of people are complaining about losing their sense of smell when they don’t feel stuffed up at all,” Datta says.
The team further experimented on nose cells, including the support cells and nerve cells sending messages to the brain using both mice and human models. This was especially performed to see if there were any signs of a link between the cells and the ACE2 receptor. A small recap: ACE2 receptor is the primary receptor in humans which the COVID-19 viruses used to attach to the host and cause infection.
The researchers from the study found that the results demonstrated a molecular signal showing that ACE2 receptors were present in nose cells and the subsidiary cells. These cells generally maintain a chemical balance in the nose, which allows the nerve cells to send smell signals to the brain.
A Contradicting study published by a team from Nicolaus Copernicus University, Poland resulted that the olfactory neurons did not pose any ACE2 receptors, implying that the novel virus cant infect the cells themselves.
It was also noticed that the timing of the onset of anosmia symptoms was varied, with some patients developing the symptoms at early stages, while another group of patients reported the loss of smell in the later stages of their illness.
How will this help in the fight against COIVD-19?
More studies need to be conducted regarding the frequency of the symptoms and the exact science behind how the COVID-19 virus affects the olfactory senses. To collect more data on the cases posing these symptoms, the AOS-HNS Infectious Disease and Patient Safety Quality Improvement Committees have developed a COVID-19 anosmia detecting tool for health care workers. Using this tool the clinicians of all specialties will be able to confidently confirm cases portraying the loss of smell.
The idea of adding the symptoms of unexplained anosmia as an official symptom of COVID-19 can help with earlier detection and isolation of potential carriers of the virus and improve safety by containing the spread of the virus.