|Industry||Digital contact tracing|
|Compatible hardware||Android & iOS smartphones|
|Physical range||~10 m (33 ft)|
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.
The Apple/Google protocol is similar to the Decentralized Privacy-Preserving Proximity Tracing (DP-3T) protocol created by the European DP-3T consortium and the Temporary Contact Number (TCN) protocol by Covid Watch, but is implemented at the operating system level, which allows for more efficient operation as a background process.Since May 2020, a variant of the DP-3T protocol is supported by the Exposure Notification Interface. Other protocols are constrained in how they operate as they have no special privilege over normal apps. This leads to issues, particularly on iOS devices where digital contact tracing apps running in the background experience significantly degraded performance. The joint approach is also designed to maintain interoperability between Android and iOS devices, which constitute the sheer majority of the market.
The ACLU stated the approach "appears to mitigate the worst privacy and centralization risks, but there is still room for improvement".In late April, Google and Apple shifted the emphasis of the naming of the system, describing it as an "exposure notification service", rather than "contact tracing" system.
Typically digital contact tracing protocols have two major responsibilities: encounter logging and infection reporting.Exposure Notification only defines encounter logging which is a decentralized architecture, with the majority of the infection reporting, currently it is centralized, being delegated to individual app implementations.
To handle encounter logging, the system uses Bluetooth Low Energy to send tracking messages to nearby devices running the protocol to discover encounters with other people. The tracking messages contain unique identifiers that are encrypted with a secret daily key held by the sending device. These identifiers change every 15–20 minutes as well as Bluetooth MAC address in order to prevent tracking of clients by malicious third parties through observing static identifiers over time. : 02:51:10
The sender's daily encryption keys are generated using a random number generator.Devices record received messages, retaining them locally for 14 days. If a user tests positive for infection, the last 14 days of their daily encryption keys can be uploaded to a central server, where it is then broadcast to all devices on the network. The method through which daily encryption keys are transmitted to the central server and broadcast is defined by individual app developers. The Google-developed reference implementation calls for a health official to request a one-time verification code (VC) from a verification server, which the user enters into the encounter logging app. This causes the app to obtain a cryptographically signed certificate, which is used to authorize the submission of keys to the central reporting server.
The received keys are then provided to the protocol, where each client individually searches for matches in their local encounter history. If a match meeting certain risk parameters is found, the app notifies the user of potential exposure to the infection.Google and Apple intend to use the received signal strength (RSSI) of the beacon messages as a source to infer proximity. RSSI and other signal metadata will also be encrypted to resist deanonymization attacks.
To generate encounter identifiers, first a persistent 32-byte private Tracing Key () is generated by a client. From this a 16 byte Daily Tracing Key is derived using the algorithm , where is a HKDF function using SHA-256, and is the day number for the 24-hour window the broadcast is in starting from Unix Epoch Time. These generated keys are later sent to the central reporting server should a user become infected.
From the daily tracing key a 16-byte temporary Rolling Proximity Identifier is generated every 10 minutes with the algorithm , where is a HMAC function using SHA-256, and is the time interval number, representing a unique index for every 10 minute period in a 24-hour day. The Truncate function returns the first 16 bytes of the HMAC value. When two clients come within proximity of each other they exchange and locally store the current as the encounter identifier.
Once a registered health authority has confirmed the infection of a user, the user's Daily Tracing Key for the past 14 days is uploaded to the central reporting server. Clients then download this report and individually recalculate every Rolling Proximity Identifier used in the report period, matching it against the user's local encounter log. If a matching entry is found, then contact has been established and the app presents a notification to the user warning them of potential infection.
Unlike version 1.0 of the protocol, version 1.1 does not use a persistent tracing key, rather every day a new random 16-byte Temporary Exposure Key() is generated. This is analogous to the daily tracing key from version 1.0. Here denotes the time is discretized in 10 minute intervals starting from Unix Epoch Time. From this two 128-bit keys are calculated, the Rolling Proximity Identifier Key () and the Associated Encrypted Metadata Key (). is calculated with the algorithm , and using the algorithm.
From these values a temporary Rolling Proximity Identifier () is generated every time the BLE MAC address changes, roughly every 15–20 minutes. The following algorithm is used: , where is an AES cryptography function with a 128-bit key, the data is one 16-byte block, denotes the Unix Epoch Time at the moment the roll occurs, and is the corresponding 10-minute interval number. Next, additional Associated Encrypted Metadata is encrypted. What the metadata represents is not specified, likely to allow the later expansion of the protocol. The following algorithm is used: , where denotes AES encryption with a 128-bit key in CTR mode. The Rolling Proximity Identifier and the Associated Encrypted Metadata are then combined and broadcast using BLE. Clients exchange and log these payloads.
Once a registered health authority has confirmed the infection of a user, the user's Temporary Exposure Keys and their respective interval numbers for the past 14 days are uploaded to the central reporting server. Clients then download this report and individually recalculate every Rolling Proximity Identifier starting from interval number , matching it against the user's local encounter log. If a matching entry is found, then contact has been established and the app presents a notification to the user warning them of potential infection.
Version 1.2 of the protocol is identical to version 1.1, only introducing minor terminology changes.
Preservation of privacy was referred to as a major component of the protocol; it is designed so that no personally identifiable information can be obtained about the user or their device.Apps implementing Exposure Notification are only allowed to collect personal information from users on a voluntary basis. Consent must be obtained by the user to enable the system or publicize a positive result through the system, and apps using the system are prohibited from collecting location data. As an additional measure, the companies stated that it would sunset the protocol by-region once they determine that it is "no longer needed".
The Electronic Frontier Foundation showed concerns the protocol was vulnerable to "linkage attacks", where sufficiently capable third parties who had recorded beacon traffic may retroactively be able to turn this information into tracking information, for only areas in which they had already recorded beacons, for a limited time segment and for only users who have disclosed their COVID-19 status, once a device's set of daily encryption keys have been revealed.
On April 16, the European Union started the process of assessing the proposed system for compatibility with privacy and data protection laws, including the General Data Protection Regulation (GDPR).On April 17, 2020, the UK's Information Commissioner's Office, a supervisory authority for data protection, published an opinion analyzing both Exposure Notification and the Decentralized Privacy-Preserving Proximity Tracing protocol, stating that the systems are "aligned with the principles of data protection by design and by default" (as mandated by the GDPR).
Exposure Notification is compatible with devices supporting Bluetooth Low Energy and running Android 6.0 "Marshmallow" or newer with Google mobile services, or iOS 13.5 or newer.On iOS, it is serviced via operating system updates. On Android, it is serviced via updates to Google Play Services (by means of Google Play), ensuring compatibility with the majority of Android devices released outside of Mainland China, and not requiring it to be integrated into an Android firmware (which would hinder deployment), although it is not compatible with Huawei devices released since May 2019 due to the US trade ban on Huawei. Apple and Google released reference implementations for apps utilizing the system, which can be used as a base.
Exposure Notification apps may only be released by public health authorities. To discourage fragmentation, each country will typically be restricted to one app, although Apple and Google stated that they would accommodate regionalized approaches if a country elects to do so.
On September 1, 2020, the consortium announced "Exposure Notifications Express" (EN Express), a system designed to ease adoption of the protocol by health authorities by removing the need to develop an app themselves. Under this system, a health authority provides parameters specific to their implementation (such as thresholds, branding, messaging, and key servers), which is then processed to generate the required functionality. On Android, this data is used to generate an app, while on iOS, the functionality is integrated directly at the system level on iOS 13.7 and newer without a dedicated app.On December 14, 2020, Apple released iOS 12.5, bringing support for Exposure Notifications to older iPhones.
The last information update on the “Exposure Notification Systems” partnership was a year end review issued by Google in December 2020: [ original research? ] The Frequently Asked Questions (FAQ) published document has not been revised since May 2020. Basic support remains provided through the apps store released by authorized public health agencies, including enforcement of the personal privacy protection framework as demonstrated on the UK NHS challenge in support of their contact tracers."we plan to keep you updated here with new information again next year". Nothing has however been issued on the one year anniversary of the launch of the “Exposure Notification Interface” API in spite of important changes on the pandemic front such as vaccination, variants, digital health passports, app adoption challenges as well as growing interest for tracking QR codes (and notifying from that basis) on a mostly airborne transmitted virus.
In June 2021, Google faced allegations that it had automatically downloaded Massachusetts' "MassNotify" app to Android devices without user consent. Google clarified that it had not actually downloaded the app to user devices, and that Google Play Services was being used to deploy an EN Express configuration profile, allowing it to be activated from the Exposure Notification section of the Google Settings app on an opt-in basis.
As of May 21, at least 22 countries had received access to the protocol.Switzerland and Austria were among the first to back the protocol. On April 26, after initially backing PEPP-PT, Germany announced it would back Exposure Notification, followed shortly after by Ireland and Italy. Despite already adopting the centralised BlueTrace protocol, Australia's Department of Health and Digital Transformation Agency are investigating whether the protocol could be implemented to overcome limitations of its COVIDSafe app. On May 25, Switzerland became the first country to launch an app leveraging the protocol, SwissCovid, beginning with a small pilot group.
In England, the National Health Service (NHS) trialed both an in-house app on a centralized platform developed by its NHSX division, and a second app using Exposure Notification.On June 18, the NHS announced that it would focus on using Exposure Notification to complement manual contact tracing, citing tests on the Isle of Wight showing that it had better cross-device compatibility (and would also be compatible with other European approaches), but that its distance calculations were not as reliable as the centralized version of the app, an issue which was later rectified. Later, it was stated that the app would be supplemented by QR codes at venues. A study of the impact of Exposure Notification in England and Wales estimated that it averted 8,700 (95% confidence interval 4,700–13,500) deaths out of the 32,500 recorded from its introduction on 24 September 2020 to 31 December 2020.
Canada launched its COVID Alert app, co-developed in partnership with BlackBerry Limited and Shopify,on July 31 in Ontario.
In May 2020, Covid Watch launched the first calibration and beta testing pilot of the GAEN APIs in the United States at the University of Arizona.In Aug 2020, the app launched publicly for a phased roll-out in the state of Arizona.
The U.S. Association of Public Health Laboratories (APHL) stated in July 2020 that it was working with Apple, Google, and Microsoft on a national reporting server for use with the protocol, which it stated would ease adoption and interoperability between states.
In August 2020, Google stated that at least 20 U.S. states had expressed interest in using the protocol. In Alabama, the Alabama Department of Public Health, University of Alabama at Birmingham, and the University of Alabama System deployed the "GuideSafe" app for university students returning to campus, which includes Exposure Notification features.On August 5, the Virginia Department of Health released its "COVIDWise" app — making it the first U.S. state to release an Exposure Notification-based app for the general public. North Dakota and Wyoming released an EN app known as "Care19 Alert", developed by ProudCrowd and using the APHL server (the app is a spin-off from an existing location logging application it had developed, based on one it had developed primarily for use by students travelling to attend college football away games).
Maryland, Nevada, Virginia, and Washington, D.C. have announced plans to use EN Express.In September, Delaware, New Jersey, New York, and Pennsylvania all adopted "COVID Alert" apps developed by NearForm, which are based on its COVID Tracker Ireland app. Later that month, the Norwegian Institute of Public Health announced that it would lead development of an Exposure Notification-based app for the country, which replaces a centralized app that had ceased operations in June 2020 after the Norwegian Data Protection Authority ruled that it violated privacy laws.
|Austria||Stopp Corona App||June 26, 2020|
|Brazil||Coronavírus-SUS||July 31, 2020|
|Belgium||Coronalert||October 1, 2020 (public)||September 2, 2020 (Pilot phase)|
|Canada||COVID Alert||July 31, 2020||Available in New Brunswick, Newfoundland and Labrador, Ontario, Manitoba, Saskatchewan, Quebec, Prince Edward Island, and Nova Scotia. Alberta and British Columbia have declined its use.|
|Czech Republic||eRouška (eMask)||September 17, 2020||Since version 2.1|
|Denmark||Smittestop||June 18, 2020|
|Estonia||Hoia||August 20, 2020|
|Finland||Koronavilkku||August 31, 2020|
|Germany||Corona-Warn-App||June 16, 2020|
|Gibraltar||BEAT Covid Gibraltar||June 18, 2020||Based on COVID Tracker Ireland and will interoperate with it.|
|Ireland||COVID Tracker Ireland||July 7, 2020|
|Italy||Immuni||June 1, 2020|
|Japan||COCOA||June 19, 2020|
|Jersey||Jersey COVID Alert||September 21, 2020|
|Latvia||Apturi Covid||May 29, 2020|
|Lebanon||Ma3an||July 16, 2020|
|Netherlands||CoronaMelder||October 10, 2020 (full release)|
|New Zealand||NZ COVID Tracer||December 10, 2020 (full release)|
|Norway||Smittestopp||December 21, 2020||Replaces a version of the app that was suspended earlier in the year due to scrutiny from the local Norwegian Data Protection Authority.|
|Philippines||StaySafe||March 29, 2021||GAEN implementation activated on April 5, 2021|
|Poland||ProteGO Safe||June 9, 2020||Update to existing encounter logging app.|
|Portugal||STAYAWAY COVID||August 28, 2020|
|Russia||Gosuslugi. Covid Tracker||November 23, 2020||https://play.google.com/store/apps/details?id=com.minsvyaz.gosuslugi.exposurenotificationdroid|
|South Africa||COVID Alert SA||September 1, 2020|
|Spain||Radar COVID||June 30, 2020 (beta test)|
|Switzerland||SwissCovid||May 26, 2020 (pilot phase)|
|Taiwan||臺灣社交距離||May 3, 2021|
|United Kingdom|| England |
|NHS COVID-19||September 24, 2020|
|Northern Ireland||StopCOVID NI||July 30, 2020||Interoperates with COVID Tracker Ireland.|
|Scotland||Protect Scotland||September 11, 2020||Based on COVID Tracker Ireland and will interoperate with it.|
|United States||Alabama||GuideSafe||August 3, 2020||Targeting University of Alabama students as part of a larger program under the same name.|
|Arizona||Covid Watch||May 28, 2020 (attenuation and dynamic risk testing) |
August 19, 2020 (released)
|Targeting University of Arizona in a phased roll-out for the state of Arizona.|
|California||CA Notify||December 10, 2020|
|Colorado||CO Exposure Notifications||October 25, 2020|
|Connecticut||COVID Alert CT||November 12, 2020|
|Delaware||COVID Alert DE||September 15, 2020||Based on COVID Tracker Ireland.|
|Guam||Guam Covid Alert||September 10, 2020||Based on the PathCheck Foundation's GAEN Mobile project|
|Hawaii||Aloha Safe Alert||November 11, 2020||Based on the PathCheck Foundation's GAEN Mobile project|
|Louisiana||COVID Defense||January 22, 2021||Based on the PathCheck Foundation's GAEN Mobile project|
|Maryland||MD COVID Alert||October 10, 2020|
|Massachusetts||MassNotify||Uses EN Express.|
|Michigan||MI COVID Alert||October 15, 2020 (Michigan State University pilot) |
November 9, 2020 (statewide)
|Minnesota||COVIDaware MN||November 23, 2020|
|Missouri||MO/Notify||July 29, 2021||Targeting Washington University in St. Louis in a phased roll-out for the state of Missouri.|
|New Jersey||COVID Alert NJ||September 30, 2020||Based on COVID Tracker Ireland.|
|New York||COVID Alert NY||September 30, 2020||Based on COVID Tracker Ireland.|
|North Carolina||SlowCOVIDNC||September 22, 2020|
|North Dakota||Care19 Alert||August 13, 2020|
|Pennsylvania||COVID Alert PA||September 24, 2020||Based on COVID Tracker Ireland.|
|Utah||UT Exposure Notifications||February 16, 2021|
|Virginia||COVIDWise||August 5, 2020|
|Washington||WA Notify||November 30, 2020|
|Wisconsin||WI Exposure Notification||December 23, 2020|
|Wyoming||Care19 Alert||August 14, 2020|
|Uruguay||Coronavirus UY||June 15, 2020|
Some countries, such as France, have pursued centralized approaches to digital contact tracing, in order to maintain records of personal information that can be used to assist in investigating cases.The French government asked Apple in April 2020 to allow apps to perform Bluetooth operations in the background, which would allow the government to create its own system independent of Exposure Notification.
On August 9, the Canadian province of Alberta announced plans to migrate to the EN-based COVID Alert from its BlueTrace-based ABTraceTogether app.This did not occur, and on November 6 Premier of Alberta Jason Kenney announced that the province would not do so, arguing that ABTraceTogether was "from our view, simply a better and more effective public health tool", and that they would be required to phase out ABTraceTogether if they did switch. British Columbia has also declined to adopt COVID Alert, with provincial health officer Bonnie Henry stating that COVID Alert was too "non-specific".
Australia's officials have stated its COVIDSafe, which is based on Singapore's BlueTrace, will not be shifting from manual intervention.
In the United States, states such as California and Massachusetts declined to use the technology, opting for manual contact tracing.California later reversed course and adopted the system in December 2020.
Chinese vendor Huawei (which cannot include Google software on its current Android products due to U.S. sanctions) added a OS-level DP-3T API known as "Contact Shield" to its Huawei Mobile Services stack in June 2020, which the company states is intended to be interoperable with Exposure Notification.
In public health, contact tracing is the process of identifying persons who may have come into contact with an infected person ("contacts") and subsequent collection of further information about these contacts. By tracing the contacts of infected individuals, testing them for infection, isolating or treating the infected, and tracing their contacts, public health aims to reduce infections in the population. Diseases for which contact tracing is commonly performed include tuberculosis, vaccine-preventable infections like measles, sexually transmitted infections, blood-borne infections, Ebola, some serious bacterial infections, and novel virus infections. The goals of contact tracing are:
iOS 12 is the twelfth major release of the iOS mobile operating system developed by Apple Inc. Aesthetically similar to its predecessor, iOS 11, it focuses less on new functions than on performance, quality improvements and security updates. Announced at the company's Worldwide Developers Conference on June 4, 2018, iOS 12 was released to the public on September 17, 2018. It was succeeded for the iPhone and iPod Touch by iOS 13 on September 19, 2019 and for the iPad by iPadOS 13 on September 24, 2019. More than three years after its initial release, iOS 12 continues to receive security updates on devices that do not support iOS 13 or newer.
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 is an app released by the Australian Government designed to allow users to access information about the COVID-19 pandemic in Australia. The app was developed by Delv Pty Ltd for the Department of Health and released on 29 March 2020. Since release the app has been downloaded over a million times and ranked first in the Apple App Store's "Health and Fitness" category. Due to the short development period of two weeks, the app initially served primarily as an aggregate of links to official government websites. Shortly after an update was released adding a voluntary "isolation registration" form that collected the location, name, age, mobile phone number, isolation start date, and various other details about users who were self isolating.
Pan-European Privacy-Preserving Proximity Tracing (PEPP-PT/PEPP) is a full-stack open protocol designed to facilitate digital contact tracing of infected participants. The protocol was developed in the context of the ongoing COVID-19 pandemic. The protocol, like the competing Decentralized Privacy-Preserving Proximity Tracing (DP-3T) protocol, makes use of Bluetooth LE to discover and locally log clients near a user. However, unlike DP-3T, it uses a centralized reporting server to process contact logs and individually notify clients of potential contact with an infected patient. It has been argued that this approaches compromises privacy, but has the benefit of human-in-the-loop checks and health authority verification. While users are not expected to register with their real name, the back-end server processes pseudonymous personal data that would eventually be capable of being reidentified. It has also been put forward that the distinction between centralized/decentralized systems is mostly technical and PEPP-PT is equally able to preserve privacy.
BlueTrace is an open-source application protocol that facilitates digital contact tracing of users to stem the spread of the COVID-19 pandemic. Initially developed by the Singaporean Government, BlueTrace powers the contact tracing for the TraceTogether app. Australia, New Zealand, and the United Arab Emirates have already adopted the protocol in their gov apps, and other countries were considering BlueTrace for adoption. A principle of the protocol is the preservation of privacy and health authority co-operation.
COVIDSafe is a digital contact tracing app announced by the Australian Government on 14 April 2020 to help combat the ongoing COVID-19 pandemic. The app is based on the BlueTrace protocol, originally developed by the Singaporean Government, and was first released on 26 April 2020. The app is intended to augment traditional contact tracing by automatically tracking encounters between users and later allowing a state or territory health authority to warn a user they have come within 1.5 metres with an infected person for 15 minutes or more.
The Temporary Contact Numbers Protocol, or TCN Protocol, is an open source, decentralized, anonymous exposure alert protocol developed by Covid Watch in response to the COVID-19 pandemic. The Covid Watch team, started as an independent research collaboration between Stanford University and the University of Waterloo was the first in the world to publish a white paper, develop, and open source fully anonymous Bluetooth exposure alert technology in collaboration with CoEpi after writing a blog post on the topic in early March.
Digital contact tracing is a method of contact tracing relying on tracking systems, most often based on mobile devices, to determine contact between an infected patient and a user. It came to public prominence in the form of COVID-19 apps during the COVID-19 pandemic. Since the initial outbreak, many groups have developed nonstandard protocols designed to allow for wide-scale digital contact tracing, most notably BlueTrace and Exposure Notification.
Decentralized Privacy-Preserving Proximity Tracing is an open protocol developed in response to the COVID-19 pandemic to facilitate digital contact tracing of infected participants. The protocol, like competing protocol Pan-European Privacy-Preserving Proximity Tracing (PEPP-PT), uses Bluetooth Low Energy to track and log encounters with other users. The protocols differ in their reporting mechanism, with PEPP-PT requiring clients to upload contact logs to a central reporting server, whereas with DP-3T, the central reporting server never has access to contact logs nor is it responsible for processing and informing clients of contact. Because contact logs are never transmitted to third parties, it has major privacy benefits over the PEPP-PT approach; however, this comes at the cost of requiring more computing power on the client side to process infection reports.
NHS COVID-19 is a voluntary contact tracing app for monitoring the spread of the COVID-19 pandemic in England and Wales. It has been available since 24 September 2020 for Android and iOS smartphones, and can be used by anyone aged 16 or over.
On April 16, 2020, Nodle released The Whisper Tracing Protocol white paper and the Coalition App on Android. The protocol is intended to be a privacy first Digital contact tracing tool developed for the 2020 COVID-19 pandemic. The project has been spun off into The Coalition Foundation. The protocol is being used for the Government of Senegal's Daancovid19 mobile contact tracing app initiative. Daancovid19 is the Senegalese digital response against the coronavirus. It was started by a handful of digital professionals and subsequently brought together nearly 500 volunteer experts from the private, public, and civil society. The respective Coalition App has been promoted by the City of Berkeley, California to their residents.
NZ COVID Tracer is a mobile software application that enables a person to record places they have visited, in order to facilitate tracing who may have been in contact with a person infected with the COVID-19 virus. The app allows users to scan official QR codes at the premises of businesses and other organisations they visit, to create a digital diary. It was launched by New Zealand's Ministry of Health on 20 May 2020, during the ongoing COVID-19 pandemic. It can be downloaded from the App Store and Google Play.
Covid Watch was an open source nonprofit founded in February 2020 with the mission of building mobile technology to fight the COVID-19 pandemic while defending digital privacy. The Covid Watch founders became concerned about emerging, mass surveillance-enabling digital contact tracing technology and started the project to help preserve civil liberties during the pandemic.
Corona-Warn-App is the official and open-source COVID-19 contact tracing app used for digital contact tracing in Germany made by SAP and Deutsche Telekom subsidiary T-Systems.
COVID Alert is the Exposure Notification service app for the country of Canada. It launched in the province of Ontario on July 31, 2020, and became available in nearly all Canadian provinces by October of that year, excluding Alberta, and British Columbia.
SwissCovid is a COVID-19 contact tracing app used for digital contact tracing in Switzerland. Use of the app is voluntary and based on a decentralized approach using Bluetooth Low Energy and Decentralized Privacy-Preserving Proximity Tracing (dp3t).
COVID Tracker Ireland is a digital contact tracing app released by the Irish Government and the Health Service Executive on 7 July 2020 to prevent the spread of COVID-19 in Ireland. The app uses ENS and Bluetooth technology to determine whether a user have been a close contact of someone for more than 15 minutes who tested positive for COVID-19. On 8 July, the app reached one million registered users within 36 hours after its launch, representing more than 30% of the population of Ireland and over a quarter of all smartphone users in the country. As of August 2021, over 3,030,000 people have downloaded the app.
Speed and scale are key to mitigation of COVID-19, due to the fat-tailed nature of pandemic risk and the exponential growth of COVID-19 infections. For mitigation to be effective, (a) chains of transmission must be broken as quickly as possible through screening and containment, (b) health care must be available to provide for the needs of those infected, and (c) contingencies must be in place to allow for effective rollout of (a) and (b).
COVID-19 Contact-Confirming Application, abbreviated as COCOA, is a COVID-19 application for smartphones provided by the Ministry of Health, Labour and Welfare of Japan. The application uses Bluetooth to detect and record suspected close contacts between users. If the contact is diagnosed with COVID-19, the user will be notified. After receiving the notification, the user can consider self-isolation or go to a medical institution for treatment.