SAN DIEGO — Previous studies confirmed the widespread notion that the loss of smell and taste were early indicators of a SARS-CoV-2 (the official name of the novel coronavirus causing COVID-19) infection. Now it seems that if you battle these strange symptoms, it may be a positive sign, despite your increased chances of being diagnosed with the virus.
Researchers at UC San Diego Health conducted further study and found that losing your sense of smell suggests a milder form of COVID-19 than other forms of the disease. The researchers said this finding could help health care providers decide who needs to be hospitalized.
“One of the immediate challenges for health care providers is to determine how to best treat persons infected by the novel coronavirus,” said first author Dr. Carol Yan, rhinologist and surgeon at UC San Diego Health, in a university release. “If they display no or mild symptoms, can they return home to self-quarantine or will they likely require hospitalization? These are crucial questions for hospitals trying to efficiently and effectively allocate finite medical resources.”
Previous studies have shown that risk factors for developing the worst cases of COVID-19 include age and underlying medical conditions such as chronic lung disease, heart conditions, obesity, and diabetes. These factors increase the severity of the disease, leading to death in many instances.
“What’s notable in the new findings is that it appears that loss of smell may be a predictor that a SARS-CoV-2 infection will not be as severe, and less likely to require hospitalization,” said Dr. Yan. “If an infected person loses that sense, it seems more likely they will experience milder symptoms, barring other underlying risk factors.”
The study was a retrospective analysis of 169 patients who tested positive for COVID-19 between March 3rd and April 8th of 2020 at UC San Diego Health. The research team gathered olfactory and gustatory data for 128 of the 169 patients, 26 of whom were hospitalized.
Patients who were hospitalized were much less likely to report anosmia, or loss of smell. 26.9% compared to 66.7% for COVID-suffering outpatients. The percentages were similar for loss of taste, or dysgeusia.
The results showed that those who reported loss of smell were 10 times less likely to be admitted to the hospital for COVID-19 than those who never suffered from loss of smell. Anosmia wasn’t associated with any other measures usually related to doctors choosing to hospitalize a patient. The researchers say this suggests the loss of smell and taste are independent factors that may indicate a milder manifestation of COVID-19.
The authors think their findings could hint at more of the pathophysiological characteristics of the infection. If the SARS-CoV-2 virus concentrates in the nose and upper airway upon initial infection, where it blocks olfactory function, the resulting infection could be less severe and sudden in onset, which can decrease the risk of overwhelming the immune system, causing respiratory failure and hospitalization.
Researchers think they could learn more about how the body responds to the infection, leading them to potentially developing a vaccine. They note that they relied on self-reported anosmia for their study.
The study was published in the International Forum of Allergy and Rhinology.