Real-time tracking of self-reported symptoms to predict potential COVID-19

Abstract

A total of 2,618,862 participants reported their potential symptoms of COVID-19 on a smartphone-based app. Among the 18,401 who had undergone a SARS-CoV-2 test, the proportion of participants who reported loss of smell and taste was higher in those with a positive test result (4,668 of 7,178 individuals; 65.03%) than in those with a negative test result (2,436 of 11,223 participants; 21.71%) (odds ratio = 6.74; 95% confidence interval = 6.31-7.21). A model combining symptoms to predict probable infection was applied to the data from all app users who reported symptoms (805,753) and predicted that 140,312 (17.42%) participants are likely to have COVID-19. COVID-19 is an acute respiratory illness caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since its outbreak in China in December 2019, over 2,573,143 cases have been confirmed worldwide (as of 21 April 2020; https://www.worldometers.info/coronavirus/). Although many people have presented with flu-like symptoms, widespread population testing is not yet available in most countries, including the United States (https://www.cdc.gov/coronavirus/2019-ncov/ cases-updates/testing-in-us.html) and United Kingdom 1. Thus, it is important to identify the combination of symptoms most predictive of COVID-19, to help guide recommendations for self-isolation and prevent further spread of the disease 2. Case reports and mainstream media articles from various countries indicate that a number of patients with diagnosed COVID-19 developed anosmia (loss of smell) 3,4. Mechanisms of action for the SARS-CoV-2 viral infection causing anosmia have been postulated 5,6. Other studies indicate that a number of infected individuals present anosmia in the absence of other symptoms 7,8 , suggesting that this symptom could be used as screening tool to help identify people with potential mild cases who could be recommended to self-isolate 9. We investigated whether loss of smell and taste is specific to COVID-19 in 2,618,862 individuals who used an app-based symptom tracker 10 (Methods). The symptom tracker is a free smartphone application that was launched in the United Kingdom on 24 March 2020, and in the United States on 29 March 2020. It collects data from both asymptomatic and symptomatic individuals and tracks in real time how the disease progresses by recording self-reported health information on a daily basis, including symptoms, hospitalization, reverse-transcription PCR (RT-PCR) test outcomes, demographic information and pre-existing medical conditions.

Self‐reported olfactory loss associates with outpatient clinical course in COVID‐19

“…Our study's findings are consistent with those of other studies evaluating both inpatient and outpatient selfreported olfactory dysfunction. [9][10][11][12]14,15 Moein et al 11 reported very high rates of measured olfactory dysfunction (98%) on quantitative analysis of COVID-19 inpatients, but only 25% showed complete anosmia and 35% selfreported smell loss. This discrepancy between quantitative and self-reported olfactory dysfunction is thought to be related to a general unawareness or underreporting of hyposmia.…”

“…Olfactory and gustatory dysfunction have recently been found to be associated with COVID-19 infection. [9][10][11][12] The growing number of Internet searches inquiring about loss of smell strongly correlates with the increased prevalence of COVID-19. 13 In ambulatory populations, patients who present with influenza-like symptoms and anosmia are 6 to 10 times more likely to test positive for COVID-19 infection.…”

“…13 In ambulatory populations, patients who present with influenza-like symptoms and anosmia are 6 to 10 times more likely to test positive for COVID-19 infection. 9,10 Indeed, 59% to 86% of outpatient COVID-19 positive patients self-reported olfactory loss. 9,10,12 Notably, self-reported anosmia in COVID-19-positive hospitalized patients has also been identified as a common symptom, but is consistently reported at lower rates in this population (5-35%).…”

“…9,10 Indeed, 59% to 86% of outpatient COVID-19 positive patients self-reported olfactory loss. 9,10,12 Notably, self-reported anosmia in COVID-19-positive hospitalized patients has also been identified as a common symptom, but is consistently reported at lower rates in this population (5-35%). 11,14,15 Although limited quantitative olfactory data exist in either outpatient or inpatient contexts, early findings in inpatients with COVID-19 suggest that only 28% self-reported smell loss and a minority (25%) demonstrated complete anosmia, despite some degree of measurable olfactory dysfunction in almost all subjects.…”

Intense bitterness of molecules: machine learning for expediting drug discovery

“…Several drugs are currently under study and clinical trial, for example: Remdesivir, an adenosine analog that was previously tested as a potential drug for Ebola and as anti-viral drug(54), showed promising result in COVID19 patients and thus was granted an FDA Emergency Use Authorization on 1 May 2020 (55). Interestingly, taste and smell loss, (56) including impairment of the bitter taste, are reported by many COVID19 patients (57). We applied BitterIntense to possible COVID19 drug candidates and compared it to the general abundance of pVB drugs in DrugBank.…”