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

Background: The purpose of this study was to create a self-administered, five-minute, at-home objective smell test to detect alterations in smell function that individuals may not notice but that increase the risk of SARS-CoV-2 infection. Sudden loss of smell or taste substantially increased the odds of COVID-19 infection; however, self-reports of smell function were unreliable predictors. The new smell test combined a physical smell card with peel-and-sniff odor labels and a web-based application accessible through a smartphone, tablet, or computer.

Materials/Methods: This study developed and evaluated the COVID Smell Test and web-based application. Each participant accessed the web-based app on their own smartphone, tablet, or computer to complete the test. The test was designed for repeated use to support longitudinal data collection. The study created a native application to conduct the longitudinal COVID Smell Test (Aim 1), collected data from asymptomatic healthcare workers, symptomatic patients, and undergraduates (Aim 2), and developed algorithms to establish personalized smell thresholds and differentiate COVID-19 related smell loss from that caused by influenza (Aim 3). The test was fully self-administered, required no specialized equipment, and was designed to be low-cost, accessible, and scalable for large populations.

Outcome/Impact: The study demonstrated that the COVID Smell Test provided a rapid, objective tool for identifying changes in smell function. The intended outcome was to improve early detection of COVID-19 infection and guide individuals on whether to avoid school or work and seek medical evaluation, thereby reducing potential transmission.