Over the past month doctors and researchers are gaining more information as we make our way through the novel Corona Covid-19 virus. We now know that a high number of patients diagnosed with Covid-19 have a sudden loss of smell (anosmia) and/or taste as a presenting symptom. Some of these patients have no other symptoms and remain otherwise well, yet testing shows they do, in fact, have the virus.
The American Academy of Otolaryngology-Head and Neck Surgery CEO, Dr. James C. Denneny, believes the symptoms could be an early warning signal and patients with acute onset loss of smell or taste should have a high index of suspicion for Covid-19 (also known as SARS-CoV-2) infection.
Since Covid-19 is extremely contagious, any early hints that someone could be carrying the virus would be a clue to get tested and go into quarantine.
The CDC puts out a weekly report calledMorbidity and Mortality Weeklyand in a study of 5000 healthcare workers who reported symptoms, 750 (16%)s wrote loss of smell or taste as an "other" symptom. Similar symptom trackers using a smartphone app showed similar numbers (18%).
Other viruses like influenza and corona virus can also affect smell and taste so these symptoms alone are not enough to diagnose Covid infection but coupled with fever, fatigue and cough, the predictive value is high. The reason for this sensory loss is not known, but there may be ACE 2 receptors on the olfactory mucosa and recent studies have shown these receptors are the entry pathway for the virus.
My hospital and clinics have incorporated the taste and smell question into our screening tool for testing. I want to note that we are still NOT doing serum testing for antibodies to Covid-19. The current tests are nasal swabs that show active infection or not.