COVID Symptom Study

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COVID Symptom Study
Covid Symptom Study App icon.png
Operating system Android, iOS
Type COVID-19 apps
Website OOjs UI icon edit-ltr-progressive.svg

The COVID Symptom Study, formerly the COVID Symptom Tracker, [1] is a COVID-19 epidemiological research mobile app developed in the United Kingdom that runs on Android and iOS. It is a collaboration between King's College London, Guy's and St Thomas' Hospitals and Zoe Global Limited, with funding granted by the UK government. The purpose of the app is to track symptoms and other salient data in a large number of people to enable epidemiological results to be calculated.



The idea for an app to track the spread of COVID-19 came from professor Tim Spector, an epidemiologist at King's College London. In the early months of 2020 he used his startup company ZOE Global Limited to build the Covid Symptom Tracker app in collaboration with King's College London and Guy's and St Thomas' hospitals. [2] [3] Initially the project was UK-based, where there is open membership. [4] In the United States at a later date[ when? ] various cohorts from existing studies were added, including from the Nurses' Health Study; this research was in collaboration with Massachusetts General Hospital. [4] The project website states that "The app is and always will be free, and any data you provide will not be used for commercial purposes." [5]

At the end of April 2020, the project received assistance from the Department of Health and Social Care which allowed it to offer up to 10,000 COVID-19 tests each week to participants. [6]

The app was released as a trial for 5,000 twins, [7] using patients involved in other Zoe research projects. [2] It was later expanded for use by non-twins. [2] The app entered the UK App Store and Play Store on 24 March, and the US App and Play stores on 29 March. [4]

In August 2020, the UK government made a grant of £2 million to support data collection by the project, [8] [9] and by August 2021, government funding amounted to £5m. [10] In May 2021, the associated company name was changed from Zoe Global Limited to Zoe Limited. [11]


Covid Symptom Tracker screenshot.PNG

Within 24 hours of being available in the UK, the app had been downloaded over 1 million times. [2] A paper using data collected in the four weeks up to 21 April 2020 analysed symptoms from 2.45 million people in the UK and 168,000 in the US. [12] As of May 2020, the app had been downloaded by over 3 million people, [4] including 2 million Britons. [13] By 17 July the number exceeded 4 million. [14]

The number of active app users is not published. In late October 2020, Spector said that a million users were reporting symptoms most days. [15] Researchers who analysed data collected in the last three months of 2020 said they used more than 65 million health reports from 1.76 million users. [16] By July 2021, the app had been used by 4.6 million people in Britain and about a quarter of that number continued to self-report every day. [10]


The COVID Symptom Study requires users to give their location. [13] Users give personal information including age, gender and location, and report if they have any underlying chronic conditions. [17] They also answer questions related to common COVID-19 symptoms, and input any illness or symptoms that they have, [4] [2] as well as stating whether they have been tested for COVID-19. [17] Beginning in May 2020, a random sample of users is selected (on the first day they report symptoms) for a swab test. [6] Researchers then use statistical analysis to determine which symptoms are likely to indicate COVID-19, [13] rather than the common cold or seasonal influenza. [2] The app does not have any contact tracing functionality. [4]

Based on the data inputted into the app, researchers estimated that when cases peaked on 1 April 2020, 2.1 million people in the UK aged between 20 and 69 may have had COVID-19, and that as of 23 May 2020, 280,000 people in that age range currently had symptoms consistent with COVID-19. [18] The study also estimates the risk level to health workers, compared with the general public. [19] Research based on the app was described in papers in Science on 5 May 2020 [20] and in Nature on 11 May 2020. [12] Using data from the app, researchers were able to identify six distinct types of COVID-19 and forecast which initial symptoms were more likely to lead to severe illnesses. [21] [22]

See also

Related Research Articles

Timothy David Spector is a British epidemiologist and science writer.

Your.MD also known as Healthily, is a digital healthtech company that uses artificial intelligence to provide users with personalised health information via a chatbot.

COVID-19 Contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

Coronavirus disease 2019 (COVID-19) is a contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The first known case was identified in Wuhan, China, in December 2019. The disease has since spread worldwide, leading to an ongoing pandemic.

COVID-19 pandemic in the United Kingdom Ongoing COVID-19 viral pandemic in the UK

The COVID-19 pandemic in the United Kingdom is part of the worldwide pandemic of coronavirus disease 2019. The virus reached the UK in late January 2020. As of 13 October 2021, there have been 9,379,286 confirmed cases and 142,293 deaths among people who had recently tested positive – the world's 22nd highest death rate by population, and with the most overall cases and second-highest death toll in Europe after Russia. There has been some disparity between the outbreak's severity in England, Scotland, Wales and Northern Ireland – health-care in the UK is a devolved matter. Each constituent country has its own publicly-funded healthcare system operated by devolved governments.

COVID-19 pandemic in Scotland Ongoing COVID-19 viral pandemic in Scotland

The COVID-19 pandemic was first confirmed to have spread to Scotland on 1 March 2020 with the positive COVID-19 test of a male Tayside resident who had recently travelled between Scotland and northern Italy. The first reported case of community transmission was on 11 March 2020 and the first reported coronavirus death in Scotland was on 13 March 2020.

Media coverage of the COVID-19 pandemic Aspect of viral outbreak

Media coverage of the COVID-19 pandemic has varied by country, time period and media outlet. News media has simultaneously kept viewers informed about current events related to the pandemic, and contributed to misinformation or fake news.

Impact of the COVID-19 pandemic on science and technology Effects or disruption to science, space and technology projects globally due to the COVID-19 pandemic economic shutdown

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COVID-19 surveillance involves monitoring the spread of the coronavirus disease in order to establish the patterns of disease progression. The World Health Organization (WHO) recommends active surveillance, with focus of case finding, testing and contact tracing in all transmission scenarios. COVID-19 surveillance is expected to monitor epidemiological trends, rapidly detect new cases, and based on this information, provide epidemiological information to conduct risk assessment and guide disease preparedness.

COVID-19 apps Mobile apps designed to aid contact tracing

COVID-19 apps are mobile software applications for digital contact tracing during the COVID-19 pandemic, i.e. the process of identifying persons ("contacts") who may have been in contact with an infected individual.

Coronavirus Australia

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The (Google/Apple) Exposure Notification (GAEN) system, originally known as the Privacy-Preserving Contact Tracing Project, is a framework and protocol specification developed by Apple Inc. and Google to facilitate digital contact tracing during the COVID-19 pandemic. When used by health authorities, it augments more traditional contact tracing techniques by automatically logging encounters with other notification system users using their Android or iOS smartphone. Exposure Notification is a decentralized reporting based protocol built on a combination of Bluetooth Low Energy technology and privacy-preserving cryptography. It is used as an opt-in feature within COVID-19 apps developed and published by authorized health authorities. Originally unveiled on April 10, 2020, it was first made available on iOS on May 20, 2020 as part of the iOS 13.5 update and on December 14, 2020 as part of the IOS 12.5 update for older iPhones. On Android, it was added to devices via a Google Play Services update, supporting all versions since Android Marshmallow.

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