Loss of taste and smell a strong predictor of COVID-19

Monash School of Public Health and Preventive Medicine researchers have just published data from Emergency Department (ED) attendances in Victoria and Tasmania during the beginning of the “second wave” throughout July – the largest study yet of patients attending EDs with suspected COVID-19. The study revealed that contact with a positive case of COVID-19 or a loss of smell or taste are good predictors of someone with the virus.

The COVID-19 Emergency Department (COVED) Quality Improvement Project is a world-first program developed by Monash University researchers to help hospital emergency departments rapidly identify and predict the outcomes of patients with COVID-19 infection.

Associate Professor Gerard O'ReillyThe project, led by Monash researcher and emergency physician at the Alfred Hospital, Associate Professor Gerard O’Reilly, has just published its latest data in the journal, Emergency Medicine Australasia.

The first COVED study, conducted at the Alfred in the first half of April 2020, showed a low positive test rate for COVID-19 in EDs with no patients with the virus requiring mechanical ventilation or dying while in the ED. The second COVED study, looking at the whole of April 2020, showed an increasing number of people attending EDs with suspected COVID-19 requiring isolation precautions.

The third COVED study, which has just been published, covered the period 1 to 31 July 2020 and looked at all ED patients attending The Alfred, St Vincent’s, Box Hill Hospitals in Melbourne, the University Hospital in Geelong, Royal Hobart, Launceston General, North-West Regional and Mersey Community Hospitals in Tasmania.

To be included in this study, the patients needed to present to the ED with suspected COVID-19, according to symptoms or epidemiological risk factors. More than 30,000 people presented to the eight EDs throughout July. Of these 2,917 met the inclusion criteria of the study with just 50 patients being positive for the virus. Of these 50, 26 were admitted to hospital, two of whom went from the ED to ICU. Two patients presenting to the ED and testing positive for COVID-19 required intubation and ventilation.

The most common presenting features amongst those presenting to the ED and testing positive for COVID-19 infection were: cough, subjective fever, and fatigue, with half reporting contact with a positive case.

According to Associate Professor O’Reilly, the low numbers of patients attending EDs who actually tested positive to the SARS-CoV-2 virus compared to the large number who appeared to have symptoms of COVID-19 indicates “a burden of suspected cases on emergency departments, requiring isolation and enhanced infection and prevention control measures, which then results in an increased length of stay in the ED, and an increased potential for ED overcrowding.”

There is a need to use data to identify, among those attending EDs with COVID-19 symptoms, those who are actually infected.”

The study found that the strongest clinical predictors of a positive SARS-CoV-2 test, among those presenting to the ED, included:

  • Self-reported fever
  • Being a non-smoker (that is, if you met the criteria for testing but were a non-smoker, then you were more likely to actually have COVID-19)
  • No increase in white blood cell count (a recent study by the CDC found elevated leukocyte or white blood cell counts in patients with severe COVID-19 illness)
  • Inflammation of both lungs or “bilateral infiltrates” on chest x ray

While Associate Professor O’Reilly said the study revealed there is no single symptom or feature that can “help a clinician be confident someone does not have COVID-19, there are several things that, if present, would make you even more confident that the patient does have COVID-19.” These include having contact with a positive case or complaining of loss of smell or taste. “If one of these exists, amongst those meeting criteria for testing, then it was highly likely that the test was positive,”
he said.

“BUT, if these did not exist, one cannot be confident to rule out COVID-19.”

We are at the forefront of urgent research to resolve and respond to COVID-19 across health, business, technology, governance, sustainability and more. Explore more COVID-19 research from Monash University.

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