forum that highlighted risk zones in various regions of the country. residents can self-report their health status and track areas with reported high rates of transmission. in the united states, contact tracing efforts varied by the respective health department in a particular state. overall, effectiveness of contact tracing data in the country was determined by the caseload assigned to contact tracers. when on-demand testing was promoted, increases in negative tests were followed by increases in hospitalizations. subsequent studies of cases and deaths found the same results. if increased testing were in response to surges, more testing should follow increases in cases, not precede them. an average of 208 extra miles were accumulated in the week following each negative test in u.s. counties. these results suggest that people who tested negative underestimated the risk of exposure when they traveled or visited. <robertson, ls. roads to covid-19 containment and spread. </new york: austin macauley, 2023.> technology three ways to sign in for contact tracing during the covid-19 pandemic in germany the age of digital contact tracing started gaining traction during the covid-19 pandemic. with widespread transmission and shortage of contact tracers, technology serves as a resource to bridge gaps. in addition, digital applications automate the process and replace the manual steps contact tracers take to track and notify exposed individuals. there are few benefits of using digital contract tracing apps over the traditional manual methods. manual methods require a skilled workforce who put in significant hours to diligently follow the steps in contact tracing. this requires a heavy investment from the government, which at times is not feasible. manual contact tracing is not suited to detect exposures unknown to the contact, as the process is limited to the interview and known knowledge. areas such as restaurants and malls make it almost impossible for the contact to know whether they have been exposed. at a theoretical scale, digital applications propose mechanism to effectively prevent and stop epidemics. during the covid-19 pandemic, manual contact tracers used technology to augment their tracing efforts. case managers in particular were a group of professionals that benefited from this resource. case management software is often used by contact tracers to maintain records of cases and contact tracing activities. this is typically a cloud database that may have specialized features such as the ability to use sms or email directly within the software to notify people believed to have been in close contact with someone carrying an infectious disease. utilizing a database, provides benefit to track persons of interest and offers a platforms to look at data points such as race, zip code, and symptoms. vendors offering contact tracing case management software include salesforce, microsoft and watkyn.app-based contact tracing during covid-19. software south korea became a pioneer in utilizing digital contact tracing tools. learning lessons from the mers outbreak in 2015, the government executed a robust contact tracing program. global positioning system (gps) technology was used to track movement of individuals and appropriately notify persons who have been exposed. the south korean government launched the corona 100m application to implement their digital contact tracing measures. the application allowed the public health agencies to track super spreader events, inform the public, and guide them to treatment if applicable. at the end of april 2020, south korea reported over 10,000 infections and 204 deaths, numbers which were vastly superior to contemporaries in the european union. singapore was among the first countries to use bluetooth technology in their contact tracing efforts. they launched the application—tracetogether—which allowed smartphones to provide proximity information useful for contact tracing . unlike south korea, which utilized a central database to track cases, the bluetooth-based apps reported information to an encrypted database that automatically deleted information after 14 days. the western world shortly followed and started developing their own bluetooth-based applications. facebook labs patented the use of bluetooth on smartphones for this in 2018. on 10 april 2020, apple and google, which account for most of the world's mobile operating systems, announced covid-19 apps for ios and android. relying on bluetooth low energy (ble) wireless radio signals for proximity information, the new tools would warn people that they had been in contact with who are infected by sars-cov-2. limitations with the use of technology, certain limitations and challenges come with the territory. tracking technology might not accurately notify individuals who have been exposed. bluetooth does not differentiate between walls and structure, prompting incorrect notification of exposures. for instance, people separated by walls in an office building can be notified as exposed, even if they never interfaced with the contact. moreover, the parameters set by the developers to contact trace vary and can miss potential cases. such parameters include proximity or distance to trigger an exposure and the timeframe in which contacts are considered to be infectious (usually 14 days). smartphone applications require people having access to smartphones and a competent infrastructure to provide internet access to the public. not all countries can provide these services to their residents. compliance is also a factor. individuals must download the application, navigate the technology, and follow appropriate directions when notified. this becomes highly difficult when the use of smartphone applications is not mandated. cohort studies which looked at the efficacy of digital contact tracing reported limited sensitivity in accurately catching cases due to the limitations mentioned above. ethical and legal issues challenges with contact tracing can arise related to issues of medical privacy and confidentiality. public health practitioners often are mandated reporters, required to act to contain a communicable disease within a broader population and also ethically obliged to warn individuals of their exposure. simultaneously, infected individuals have a recognized right to medical confidentiality. public health teams typically disclose the minimum amount of information required to achieve the objectives of contact tracing. for example, contacts are only told that they have been exposed to a particular infection, but not informed of the person who was the source of the exposure. in the united states, hipaa is a legal measure for protecting health information. this ensures sharing of only relevant information in the contact tracing process. however, given the unprecedented spread and mortality of sars-cov2, advocacy groups argue the protections offered by hipaa are spread thin. some activists and health care providers have expressed concerns that contact tracing may discourage persons from seeking medical treatment for fear of loss of confidentiality and subsequent stigma, discrimination, or abuse. this has been of particular concern regarding contact tracing for hiv. public health officials have recognized that the goals of contact tracing must be balanced with the maintenance of trust with vulnerable populations and sensitivity to individual situations. privacy is still a concern even if individual information is not disclosed by public health practitioners. the data collected in databases by governments and tech companies could be utilized for unrelated purposes. big tech companies have access to data which provides insight on where people visit, what types of interests they pursue, and who interacts with each other. therefore, questions regarding the extent of data collected, how long the information is stored, who it is shared with, and for what purpose it is being utilized come with serious ethical considerations. contact tracing efforts miss vulnerable and under resourced populations. manual tracing efforts face difficulty tracking hard to reach individuals given social complexities. digital tools require a smart phone and a reliable internet connection, two factors that might exclude certain individuals from benefiting from the technology. data is still pre-mature as to the efficacy of digital tools. some stakeholders argue whether it is appropriate to shift contact tracing into a complete digital capacity. safeguards become topics of contention when designing digital contact tracing tools. restrictions on which tracking software such as gps, wi-fi, and bluetooth are used and when those services are turned on are debated among stakeholders. who has access to the date is an important ethical issue as well. centralized vs. de-centralized databases have been implemented across the world during the covid-19 pandemic. the culture within a nation and those who run the government have a huge role in deciding in what players have access to data. therefore, governing bodies have to consider ethical principles related to transparency and accountability to the public. moreover, whether participating in contact tracing efforts should be voluntary or mandatory is another ethical dilemma that adds to the complexity of implementation. as noted above, there are numerous ethical and legal factors that go into implementation of contact tracing. executing a robust contact tracing program requires resources, skilled professionals, and an ethical framework that complies with the fabric of a particular nation.