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Smell test for COVID transmission 'high impact and cost effective’ — University of Colorado

In a perfect world, the entrance to every office, restaurant and school would offer a coronavirus test – one with absolute accuracy, and able to instantly determine who was virus-free and safe to admit and who, positively infected, should be turned away. That reality does not exist. But, reports The New York Times, as the world struggles to regain a semblance of normal life amid the uncontrolled spread of the virus, some scientists think that a quick test consisting of little more than a stinky strip of paper might at least get us close.

The test does not look for the virus itself, nor can it diagnose disease. Rather, it screens for one of COVID-19’s trademark signs: the loss of the sense of smell.

The report says since early last year, many researchers have come to recognise the symptom, which is also known as anosmia, as one of the best indicators of an ongoing coronavirus infection, capable of identifying even people who don’t otherwise feel sick.

A smell test cannot flag people who contract the coronavirus and never develop any symptoms at all. But, the report says, in a study that has not yet been published in a scientific journal, a mathematical model showed that sniff-based tests, if administered sufficiently widely and frequently, might detect enough cases to substantially drive transmission down.

Daniel Larremore, an epidemiologist at the University of Colorado-Boulder, and the study’s lead author, stressed that his team’s work was still purely theoretical. Although some smell tests are already in use in clinical and research settings, the products tend to be expensive and laborious to use and are not widely available. And in the context of the pandemic, there is not yet real-world data to support the effectiveness of smell tests as a frequent screen for the coronavirus.

A reliable smell test offers many potential benefits. It could catch far more cases than fever checks, which have largely flopped as screening tools for COVID-19.

A smell test could also come with an appealingly low price tag, perhaps as low as US50c per card, said Dr Derek Toomre, a cell biologist at Yale University and an author on Larremore’s paper. Toomre hopes that his version will fit the bill.

 

Study details
Modeling the effectiveness of olfactory testing to limit SARS-2-CoV transmission

Daniel B Larremore, Derek Toomre, Roy Parker

Published in medRxiv on 30 November 2020

Abstract
A central problem in the COVID-19 pandemic is that there is not enough testing to prevent infectious spread of SARS-CoV-2, causing surges and lockdowns with human and economic toll. Molecular tests that detect viral RNAs or antigens will be unable to rise to this challenge unless testing capacity increases by at least an order of magnitude while decreasing turnaround times. Here, we evaluate an alternative strategy based on the monitoring of olfactory dysfunction, a symptom identified in 76-83% of SARS-CoV-2 infections—including those that are otherwise asymptomatic—when a standardized olfaction test is used. We model how screening for olfactory dysfunction, with reflexive molecular tests, could be beneficial in reducing community spread of SARS-CoV-2 by varying testing frequency and the prevalence, duration, and onset time of olfactory dysfunction. We find that monitoring olfactory dysfunction could reduce spread via regular screening, and could reduce risk when used at point-of-entry for single-day events. In light of these estimated impacts, and because olfactory tests can be mass produced at low cost and self-administered, we suggest that screening for olfactory dysfunction could be a high impact and cost effective method for broad COVID-19 screening and surveillance.

 

[link url="https://www.nytimes.com/2021/01/19/health/smell-test-for-covid.html"]Full report in The New York Times[/link]

 

[link url="https://www.medrxiv.org/content/10.1101/2020.11.30.20241174v2"]medRxiv study[/link]

 

See also from MedicalBrief's Archives:
 

[link url="hhttps://www.medicalbrief.co.za/archives/smell-tests-should-be-part-of-routine-covid-19-screenings-stat-news/"]Smell tests should be part of routine COVID-19 screenings[/link]

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