Longitudinal At Home Smell Testing to Detect Infection by SARS-CoV-2

Abstract:Self-report of sudden loss of smell or taste substantially increases the odds of being infected with SARS-CoV-2(10 - 37-fold). However, self-report of smell function is an unreliable predictor of smell loss. Based on ourexperience developing smell tests with personalized algorithms for asymptomatic detection of Alzheimer'sdisease, we created a self-administered easy to use "at home" 5-minute objective smell test to uncoveralterations in smell function unbeknownst to many individuals, and confer increased risk of infection by SARS-CoV-2. Our new smell test consists of a physical smell card containing peel and sniff odor labels and a web-based application. The disposable smell card reduces the risk that the smell test serves as a vector oftransmission to other patients, research staff, and to health care workers. Each participant accesses the web-based app on their own smartphone, tablet, or computer. In our pilot studies, we validated each participant'sCOVID status by extracting results of clinical SARS-CoV-2 RT PCR assays from electronic health records. Thesmell test provides better area under the curve for SARS-CoV-2 infection (0.83 - 0.85) in both US andArgentinian symptomatic patients (ages 19 - 87) than symptom tracking alone (0.66). We are expanding thesmell test from one smell card with three odors to 6 smell cards, each with 3 different odors (18 odors total).Having six different versions of the smell card will afford longitudinal screening several times per week andprovide data to construct personalized thresholds for changes in olfactory function - each person serving astheir own control and monitoring for diminishment of their expected performance based on their personaltrajectory rather than being based on population norms. Here we propose to develop a native app to conductlongitudinal COVID Smell Test (Aim 1), collect data on asymptomatic health care workers, symptomaticpatients, and undergraduates (Aim 2) and develop algorithms for the longitudinal smell test for personalizedthresholds, differentiate smell loss from COVID relative to influenza, and assess risk of developing pulmonarydisease in COVID infected patients (Aim 3). The Longitudinal COVID Smell Test is accessible, affordable, andreadily scalable. Effective screening with the COVID smell test will better inform students and employees ifthey should not report to school or work, and seek an evaluation by a healthcare professional and moleculartesting at an early, often asymptomatic, stage of the disease.