Loss of smell should be recognized symptom of COVID-19, researchers say

Four out of five people experiencing the recent loss of smell or taste tested positive for novel coronavirus (COVID-19) antibodies, and of those who tested positive, 40 percent did not have cough or fever, according to a new study published in the journal PLOS Medicine.

COVID-19 can cause loss of taste and smell, but the prevalence of COVID-19 antibodies in people reporting these symptoms is unknown, and the significance of loss of smell or taste as a predictor of COVID-19 is not well understood, the researchers said in a statement.

To estimate the seroprevalence of SARS-CoV-2 antibodies in people with acute loss of their sense of smell or taste, the researchers enrolled 590 people self-reporting a loss of taste or smell in the previous month. Following verification of symptoms via a telemedicine consultation, 567 participants with smell or taste loss participants underwent a SARS-CoV-2 antibodies test.

The study found 78 percent had SARS-CoV-2 antibodies, and participants with loss of smell were almost three times more likely to have SARS-CoV-2 antibodies compared to those with loss of taste, suggesting that a loss of smell is a highly specific symptom of COVID-19. Of the participants testing positive for antibodies, 40 percent had neither cough nor fever.

While the study had limitations, such as the self-reporting of smell or taste changes and the lack of a control group, the researchers said they believe the evidence indicates that loss of smell should be taken into greater consideration in COVID-19 public health measures such as testing, case isolation, and treatment strategies.

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