Tracing the Untraceables: A Joint Outbreak Investigation With Law Enforcement Using a Geographic Information System.

The application of geospatial data often allows the tracing of people who are involved in activities of an illegal nature. In June 2021, we estimated the true magnitude of the spread of COVID-19 within the networks of escort-karaoke bars in Seoul, Republic of Korea, using geographic information system (GIS)-based contact tracing that was applied to our epidemiological investigation. Our joint rapid response team, composed of epidemic investigation officers and police personnel, identified 19 paper-traced cases and 158 GIS-traced cases from 5,692 confirmed cases in Seoul during the study period (June to July 2021). Our findings suggest that collaboration with law enforcement agencies and the use of overlaid satellite imagery in outbreak investigations enhances high vigilance and reduces the risk of potential breaches of human rights in the process.

Are we heroes or couriers? A phenomenological study on reappropriation of professional subjectivity and agency among health professionals during COVID-19 contact tracing in Türkiye.

During the COVID-19 pandemic, Türkiye implemented a distinctive contact tracing approach involving in-person home visits by medical professionals to individuals who tested positive for the virus. This study examines the experiences of health professionals involved in contact tracing, exploring how they reappropriated their professional subjectivity and agency during their deployment in this role. It is an interpretive phenomenological qualitative study. We conducted 21 semi-structured in-depth interviews, subsequently carried out two separate focus group interviews with an additional 31 participants from various districts in Istanbul. Participants were selected from different medical professions (i.e. doctors, nurses, midwives), career stages, gender and age groups, and hierarchical levels (i.e. officers and directors). Data analysis was conducted collaboratively by the research team from sociology and public health disciplines. Our main finding is that for the majority of health professionals, contact tracing was a novel experience with challenges and ambivalances. Yet, regardless of their perceptions (positive, negative, or mixed), the experience promoted a reaffirmation of professional identity and reappropriation of professional subjectivity and agency, which discloses that professional subjectivity is not firm but dynamic, carrying stability as well as flexibility and adjustment. Four main themes are identified in their reappropriation of professional subjectivity and agency: uncovering professional fulfillment, feeling restrained in professional dissatisfaction, assessing the job, and engaging in professional and bureaucratic negotiations.The profound exploration into the dynamics of contact tracing amidst the pandemic illuminates a multidimensional narrative that transcends the conventional discourse on physical and psychological stress experienced by medical professionals. Contact tracing experience had a transformative impact on meaning and purpose of professional identity. Our findings highlight a need for a balanced approach between centralized decision-making, mobilization of professionals, quantitative evaluation, and professional autonomy and discretion, qualitative assessments, and meaningful engagement.

Between Technological Utopia and Dystopia: Online Expression of Compulsory Use of Surveillance Technology.

This study investigated people's ethical concerns of surveillance technology. By adopting the spectrum of technological utopian and dystopian narratives, how people perceive a society constructed through the compulsory use of surveillance technology was explored. This study empirically examined the anonymous online expression of attitudes toward the society-wide, compulsory adoption of a contact tracing app that affected almost every aspect of all people's everyday lives at a societal level. By applying the structural topic modeling approach to analyze comments on four Hong Kong anonymous discussion forums, topics concerning the technological utopian, dystopian, and pragmatic views on the surveillance app were discovered. The findings showed that people with a technological utopian view on this app believed that the implementation of compulsory app use can facilitate social good and maintain social order. In contrast, individuals who had a technological dystopian view expressed privacy concerns and distrust of this surveillance technology. Techno-pragmatists took a balanced approach and evaluated its implementation practically.

New framework to assess tracing and testing based on South Korea's response to COVID-19.

South Korea's remarkable success in controlling the spread of COVID-19 during the pre-Omicron period was based on extensive contact tracing and large-scale testing. Here we suggest a general criterion for tracing and testing based on South Korea's experience, and propose a new framework to assess tracing and testing. We reviewed papers on South Korea's response to COVID-19 to capture its concept of tracing and testing. South Korea expanded its testing capabilities to enable group tracing combined with preemptive testing, and to conduct open testing. According to our proposed model, COVID-19 cases are classified into 4 types: confirmed in quarantine, source known, source unknown, and unidentified. The proportion of the first two case types among confirmed cases is defined as "traced proportion", and used as the indicator of tracing and testing effectiveness. In conclusion, South Korea successfully suppressed COVID-19 transmission by maintaining a high traced proportion (> 60%) using group tracing in conjunction with preemptive testing as a complementary strategy to traditional contact tracing.

Digital interventions for STI and HIV partner notification: a scoping review.

BACKGROUND: Partner notification (PN) is key to the control of sexually transmitted infections (STIs) and human immunodeficiency virus (HIV). Digital interventions have been used to facilitate PN. A scoping review was conducted to describe the interventions used, user preferences and acceptability of digital PN interventions from patient and partner perspectives. METHODS: A systematic literature search was conducted of eight databases for articles published in English, available online with digital PN outcome data. Articles were assessed using the Mixed Methods Appraisal Tool. Quantitative and qualitative data were synthesised and analysed using thematic analysis. RESULTS: Twenty-six articles met the eligibility criteria. Articles were heterogeneous in quality and design, with the majority using quantitative methods. Nine articles focused solely on bacterial STIs (five on syphilis; four on chlamydia), one on HIV, two on syphilis and HIV, and 14 included multiple STIs, of which 13 included HIV. There has been a shift over time from digital PN interventions solely focusing on notifying partners, to interventions including elements of partner management, such as facilitation of partner testing and treatment, or sharing of STI test results (between index patients and tested sex partners). Main outcomes measured were number of partners notified (13 articles), partner testing/consultation (eight articles) and treatment (five articles). Relationship type and STI type appeared to affect digital PN preferences for index patients with digital methods preferred for casual rather than established partner types. Generally, partners preferred face-to-face PN. CONCLUSION: Digital PN to date mainly focuses on notifying partners rather than comprehensive partner management. Despite an overall preference for face-to-face PN with partners, digital PN could play a useful role in improving outcomes for certain partner types and infections. Further research needs to understand the impact of digital PN interventions on specific PN outcomes, their effectiveness for different infections and include health economic evaluations.

A Multidisciplinary "One Health" Tool for Tackling Brucellosis.

Introduction: The Epizootiological Investigation Form (EIF) is a document issued for every notified human brucellosis case, with the aim to convey information from public health to veterinary authorities for farm animals epidemiologically linked with the patient. We assessed the integration of EIF to the routine collaboration among stakeholders and the efficiency in directing the veterinary efforts to identify Brucella-infected animals. Methods: EIFs were evaluated for the implementation, timeliness, and completeness of the shared information provided by the public health and the veterinary authorities. The efficiency of EIFs in identifying infected farms was compared with the Brucella infection rate of routinely screened farms in the frame of the national brucellosis program. Results: During 2017-2022, 344 EIFs were issued for equal number of human brucellosis cases and 118 (34.3%) were circulated successfully among all stakeholders, whereas 226 (65.7%) went missing. The highest rate of intersectoral circulation occurred in May (47.8%, p = 0.007). Veterinary investigation was performed, and result was provided in 62 (57.4%) of the 108 circulated EIFs that disclosed the contact details of the epidemiologically linked animal farms. Brucella was detected at a significantly higher rate (51.7%) in the investigated sheep and goats' farms than the infection rate (2.7%) of the national brucellosis program (p < 0.00001). Among the screened bovine herds, two were found infected of the eight tested (25%). The circulation among all competent authorities of EIFs with a farm screening outcome required a median (interquartile range) of 50 days (22, 88). The likelihood of a "complete" EIF per human case differed among geographic Regions (p = 0.010), and was higher for patients diagnosed in April (p = 0.001) and occupied as stockbreeders (p = 0.025). Conclusions: EIF is a useful tool for pinpointing suspected animals for brucellosis screening. Training of the collaborating personnel is essential for improving the implementation of EIF in the everyday practice.

Infection Risk Prediction in Healthcare Settings: Lessons from COVID-19 Contact Tracing.

Objective: Contact tracing aids epidemic control by enabling early detection and isolation without overburdening healthcare systems despite potential challenges. This study aimed to evaluate the practical application of contact and risk assessment-based models in predicting SARS-CoV-2 infection following exposure among healthcare workers in a large tertiary public university hospital in Türkiye. Materials and Methods: The study was designed as a retrospective cohort study, including contact tracing data from 3389 exposed healthcare workers from March 23, 2020, to October 22, 2021. Contact-based (mask use, contact duration and distance) and exposure risk-assessment-based (low, medium, high-risk) models with and without having symptoms were generated using logistic regression. SARS-CoV-2 infection was defined as having a positive SARS-CoV-2 RT-PCR test result. Adjustments were made to the models for demographic and occupational variables, previous infection, and vaccination. Model parameters were compared. Results: Of 3389 exposed healthcare workers, 2451 underwent RT-PCR testing. Among those tested, RT-PCR positivity was 5.9% (144/2451). Lack of personal protective equipment use (odds ratio [OR]=1.64, 95% confidence interval [CI]=1.03-2.66) and ≥15 minutes of contact duration (1.89, 1.21-3.09) were significantly associated with RT-PCR positivity. In the risk-assessment model, being a high-risk contact increased the odds of RT-PCR positivity (OR=2.76, 95% CI=1.61-5.03). Adding the presence of symptoms to contact-based and risk assessment models improved model parameters (Akaike information criterion [AIC]: from 1086.1 to 1083.1; Tjur's R2: from 0.016 to 0.019, respectively). Conclusion: The inclusion of being symptomatic improved the contact-based and risk assessment-based models. Institutions should be encouraged to incorporate symptom inquiries into risk assessment protocols in response to newly emerging respiratory virus epidemics. Institutions lacking the capacity for extensive contact tracing are recommended, at minimum, to track symptomatic exposed workers for epidemic control.

Exploring individual's public trust in the NHS Test and Trace System - A pragmatic reflexive thematic analysis.

Context: Digital contact tracing uses automated systems and location technology embedded on smartphone software for efficient identification of individuals exposed to COVID-19. Such systems are only effective with high compliance, yet compliance is mediated by public trust in the system. This work explored the perception of individual's trust and expectation of the broader Test and Trace system in the United Kingdom (UK) with the upcoming release of the National Health Service's (NHS) COVID-19 app as a case example. Methods: Twelve adults underwent online semi-structured interviews in August 2020, prior to public availability of the COVID-19 app. Pragmatic reflexive thematic analysis was applied inductively to explore common themes between participants, using an organic and recursive process (Braun & Clarke, 2019). Results: Themes highlighted features of the technology that would be perceived to be trustworthy (Theme 1), and concerns relating to i) whether users would comply with a T&T system (Theme 2) and ii) how a T&T system would handle user's personal data (Theme 3). Two further themes built on aspects of automation within a T&T system and its impact on trust (Theme 4) and how the media altered perceptions of the T&T system (Theme 5). Conclusions: Participants outlined the need for different user requirements that could be built into the NHS COVID-19 app that would support increased adherence. Concurrently, participants raised questions surrounding personal data and privacy of their data, plus the level of automated versus manual tasks, which impacted perception of trust in the app and wider system. Additionally, themes highlighted that T&T systems do not happen within a vacuum, but within a pre-existing environment influenced by variables such as the media and perception of other's compliance to T&T. Implications: Since it's roll-out, controversies surrounding the UK T&T system include concerns about privacy, stigma and uptake. Considering the current piece of work, which anticipated similar concerns prior to public access to COVID-19 app, engaging with the public may have been an important step in improving the perception and compliance with the app. Principles fundamental to patient and public involvement (PPI) and Responsible Research and Innovation (RRI) such as the inclusion of the public in the early development of research and aligning the outcomes of research and innovation with broader societal values and expectations would have been well-applied to this system and should be applied to future autonomous systems requiring high public uptake.

An evaluation of the COVID-19 self-service digital contact tracing system in New Zealand.

BACKGROUND: Digital contact tracing (DCT) aims to improve time-to-isolation (timeliness) and find more potentially exposed individuals (sensitivity) to enhance the utility of contact tracing. The aim of this study was to evaluate the public uptake of a DCT self-service survey and its integration with the Bluetooth exposure notification system within the New Zealand Covid Tracer App (NZCTA). METHODS: We adopted a retrospective cohort study design using community COVID-19 cases from February 2022 to August 2022 in New Zealand (1.2 million cases). We examined the proportion of cases completing a self-service survey and the time to complete the survey by age, sex and ethnicity. RESULTS: Overall, 66 % of cases completed their self-service survey. Completion was influenced by age, sex and ethnicity. The median completion time was 1.8 h (IQR 0.2, 17.2), with 95 % of those completing this survey doing so within 48 h of case identification. Around 13 % of all survey completers also uploaded their Bluetooth data, which resulted in an average of 663 cases per day notifying 4.5 contacts per case. CONCLUSION: The combination of high public uptake and rapid response times suggest self-service DCT could be a useful tool for future outbreaks, particularly if implemented in conjunction with manual processes and other DCT tools (e.g. Bluetooth) to address issues related to performance (sensitivity, timeliness), effectiveness, and health equity.

Population and contact tracer uptake of New Zealand's QR-code-based digital contact tracing app for COVID-19.

This study aimed to understand the population and contact tracer uptake of the quick response (QR)-code-based function of the New Zealand COVID Tracer App (NZCTA) used for digital contact tracing (DCT). We used a retrospective cohort of all COVID-19 cases between August 2020 and February 2022. Cases of Asian and other ethnicities were 2.6 times (adjusted relative risk (aRR) 2.58, 99 per cent confidence interval (95% CI) 2.18, 3.05) and 1.8 times (aRR 1.81, 95% CI 1.58, 2.06) more likely than Maori cases to generate a token during the Delta period, and this persisted during the Omicron period. Contact tracing organization also influenced location token generation with cases handled by National Case Investigation Service (NCIS) staff being 2.03 (95% CI 1.79, 2.30) times more likely to generate a token than cases managed by clinical staff at local Public Health Units (PHUs). Public uptake and participation in the location-based system independent of contact tracer uptake were estimated at 45%. The positive predictive value (PPV) of the QR code system was estimated to be close to nil for detecting close contacts but close to 100% for detecting casual contacts. Our paper shows that the QR-code-based function of the NZCTA likely made a negligible impact on the COVID-19 response in New Zealand (NZ) in relation to isolating potential close contacts of cases but likely was effective at identifying and notifying casual contacts.

Contact tracing management of a measles case in a paediatric hospital: experience of the local public health unit, Portugal, January 2024.

In January 2024, a child was diagnosed with measles in a paediatric hospital in Lisbon. Of 123 contacts, 39 (32%) were not fully immunised, presenting a risk for a potential outbreak. The public health unit initiated control measures and identified challenges during the response, such as the lack of interoperability between information systems and accessing vaccination records. The lessons learned prompted changes to national contact tracing procedures for measles, further strengthening Portugal's preparedness.

A review of chronic wasting disease (CWD) spread, surveillance, and control in the United States captive cervid industry.

Chronic wasting disease (CWD) is a fatal prion disease of the family Cervidae that circulates in both wild and captive cervid populations. This disease threatens the health and economic viability of the captive cervid industry, which raises cervids in contained spaces for purposes such as hunting and breeding. Given the high transmissibility and long incubation period of CWD, the introduction and propagation of the infectious prion protein within and between captive cervid farms could be devastating to individual facilities and to the industry as a whole. Despite this risk, there does not yet exist a literature review that summarizes the scientific knowledge, to date, about CWD spread, surveillance, or control measures. Our review, which focused on peer reviewed, primary research conducted in the United States, sought to address this need by searching Google Scholar, Scopus, and Web of Science with a five-term keyword string containing terms related to the (1) location, (2) species affected, (3) disease, (4) captive cervid industry, and (5) topic of focus. Between the three databases, there were 190 articles that were selected for further examination. Those articles were then read to determine if they were about CWD spread, surveillance, and/or control in captive cervid facilities. The 22 articles that met these inclusion criteria were evaluated in detail and discussed, with recommendations for future collaborative work between captive cervid owners, government agencies, and researchers. This work will help to address, inform, and mitigate the rising problem of CWD spread and establishment.

Estimating the impact of test-trace-isolate-quarantine systems on SARS-CoV-2 transmission in Australia.

BACKGROUND: Australian states and territories used test-trace-isolate-quarantine (TTIQ) systems extensively in their response to the COVID-19 pandemic in 2020-2021. We report on an analysis of Australian case data to estimate the impact of test-trace-isolate-quarantine systems on SARS-CoV-2 transmission. METHODS: Our analysis uses a novel mathematical modelling framework and detailed surveillance data on COVID-19 cases including dates of infection and dates of isolation. First, we directly translate an empirical distribution of times from infection to isolation into reductions in potential for onward transmission during periods of relatively low caseloads (tens to hundreds of reported cases per day). We then apply a simulation approach, validated against case data, to assess the impact of case-initiated contact tracing on transmission during a period of relatively higher caseloads and system stress (up to thousands of cases per day). RESULTS: We estimate that under relatively low caseloads in the state of New South Wales (tens of cases per day), TTIQ contributed to a 54% reduction in transmission. Under higher caseloads in the state of Victoria (hundreds of cases per day), TTIQ contributed to a 42% reduction in transmission. Our results also suggest that case-initiated contact tracing can support timely quarantine in times of system stress (thousands of cases per day). CONCLUSION: Contact tracing systems for COVID-19 in Australia were highly effective and adaptable in supporting the national suppression strategy from 2020-21, prior to the emergence of the Omicron variant in November 2021. TTIQ systems were critical to the maintenance of the strong suppression strategy and were more effective when caseloads were (relatively) low.

Expert Recommendations from the AEDV on Legal Aspects Surrounding the Management of Sexually Transmitted Diseases. / Recomendaciones de expertos de la AEDV sobre los aspectos legales en el manejo de las infecciones de transmisión sexual.

The incidence of sexually transmitted diseases has been on the rise in our setting for decades. These infections represent not only an individual problem, but also a problem of public health. Therefore, the management of STDs involves reducing community incidence, which means that common issues in the clinical practice such as failure to attend may become a more complex problem, which adds to the difficult and delicate task of locating sexual contacts that would benefit from screening and the appropriate treatment. On the other hand, STDs have direct legal implications in cases of underage patients, or suspected sexual assault. Therefore, the correct handling of these scenarios requires knowledge of the legal framework that regulates them. Dermatologists are clinically trained and prepared to deal with these conditions. Nonetheless, the legal issues involved are often difficult to solve. This document stands as a simple reference guide to help solve the main legal issues we may encounter in a consultation when dealing with STDs.

TB index case tracing in the Roma community in the Czech Republic.

Tuberculosis (TB) contact tracing and TB preventive treatment are key tools in preventing the transmission of TB with the aim of eliminating the disease. Our study seeks to demonstrate how the infection spread from an individual patient to the entire community and how proactive contact tracing facilitated prompt diagnosis and treatment. Our work was conducted as a retrospective analysis of the spread of TB infection within the Roma community in the Czech Republic, following the case of an index patient who succumbed to pulmonary TB. Several levels of care and preventive and treatment measures are outlined. Confirming the identity of the Mycobacterium tuberculosis strain was achieved using molecular methods. Among the 39 individuals examined, TB disease was detected in eight patients and TB infection was detected in six patients. The investigation of contacts within this group yielded positive results in 36% of cases, necessitating treatment. The study's findings provide evidence that actively tracing individuals at risk can lead to early detection of cases, prompt treatment, and prevention of further disease transmission. The study also indicates that the highest risk of infection occurs within the sick person's household and that young children under the age of 5 are most susceptible to falling ill.

Risk of Severe Acute Respiratory Syndrome Coronavirus 2 Transmission in Seoul, Korea.

BACKGROUND: The risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission during the endemic phase may vary from that during the previous pandemic phase. We evaluated the risk of infection in a general population with laboratory-confirmed coronavirus disease 2019 (COVID-19) in a community setting in Korea. MATERIALS AND METHODS: This study included 1,286 individuals who had been in contact with an index COVID-19 case between January 24, 2020, and June 30, 2022. Variables such as age, sex, nationality, place of contact, level of contact, the status of exposed cases, period, and level of mask-wearing were assessed. RESULTS: Among 1,286 participants, 132 (10.30%) were confirmed to have COVID-19. With increasing age, the risk of the exposed persons contracting COVID-19 from index cases tended to increase (P <0.001), especially for people in their 70s (odds ratio = 1.24, 95% confidence interval: 1.11 - 1.40, P <0.001). We found an increasing trend in the risk of a COVID-19 exposed case becoming a secondary infection case (P <0.001) in long-term care facilities where the attack rate was high. CONCLUSION: The risk of COVID-19 transmission is high in long-term care facilities where many older adults reside. Intensive management of facilities at risk of infection and strict mask-wearing of confirmed COVID-19 cases are necessary to prevent the risk of COVID-19 infection.

The Roles of Trust in Government and Sense of Community in the COVID-19 Contact Tracing Privacy Calculus: Mixed Method Study Using a 2-Wave Survey and In-Depth Interviews.

BACKGROUND: Contact tracing technology has been adopted in many countries to aid in identifying, evaluating, and handling individuals who have had contact with those infected with COVID-19. Singapore was among the countries that actively implemented the government-led contact tracing program known as TraceTogether. Despite the benefits the contact tracing program could provide to individuals and the community, privacy issues were a significant barrier to individuals' acceptance of the program. OBJECTIVE: Building on the privacy calculus model, this study investigates how the perceptions of the 2 key groups (ie, government and community members) involved in the digital contact tracing factor into individuals' privacy calculus of digital contact tracing. METHODS: Using a mixed method approach, we conducted (1) a 2-wave survey (n=674) and (2) in-depth interviews (n=12) with TraceTogether users in Singapore. Using structural equation modeling, this study investigated how trust in the government and the sense of community exhibited by individuals during the early stage of implementation (time 1) predicted privacy concerns, perceived benefits, and future use intentions, measured after the program was fully implemented (time 2). Expanding on the survey results, this study conducted one-on-one interviews to gain in-depth insights into the privacy considerations involved in digital contact tracing. RESULTS: The results from the survey showed that trust in the government increased perceived benefits while decreasing privacy concerns regarding the use of TraceTogether. Furthermore, individuals who felt a connection to community members by participating in the program (ie, the sense of community) were more inclined to believe in its benefits. The sense of community also played a moderating role in the influence of government trust on perceived benefits. Follow-up in-depth interviews highlighted that having a sense of control over information and transparency in the government's data management were crucial factors in privacy considerations. The interviews also highlighted surveillance as the most prevalent aspect of privacy concerns regarding TraceTogether use. In addition, our findings revealed that trust in the government, particularly the perceived transparency of government actions, was most strongly associated with concerns regarding the secondary use of data. CONCLUSIONS: Using a mixed method approach involving a 2-wave survey and in-depth interview data, we expanded our understanding of privacy decisions and the privacy calculus in the context of digital contact tracing. The opposite influences of privacy concerns and perceived benefit on use intention suggest that the privacy calculus in TraceTogether might be viewed as a rational process of weighing between privacy risks and use benefits to make an uptake decision. However, our study demonstrated that existing perceptions toward the provider and the government in the contact tracing context, as well as the perception of the community triggered by TraceTogether use, may bias user appraisals of privacy risks and the benefits of contact tracing.

Barriers to adopting digital contact tracing for COVID-19: Experiences in New Zealand.

BACKGROUND: Digital contact tracing (DCT) was a central component of the global response to containing COVID-19. Research has raised concerns that DCT could exacerbate inequities, yet the experiences of diverse communities at greater risk from COVID-19 are typically underrepresented. METHODS: The present study aimed to understand the perceived barriers to the adoption of the app amongst Maori, Pasifika, and disabled people. Focus groups and interviews were undertaken with Maori, Pasifika, and disability sector stakeholders and community participants. RESULTS: Participants (n = 34) generally expressed willingness to utilise DCT and support its adoption within the communities. Simultaneously, participants revealed how the app could marginalise community members who struggled with the usability and those distrusting of the government's COVID-19 interventions. CONCLUSIONS: The findings highlight how addressing communication inequality can assist in the development of contact-tracing responses that are both effective and equitable. The study provides insights about the role of information and communication technologies as health resources. PATIENT OR PUBLIC CONTRIBUTION: Consulting with members of the target communities was central throughout the present study, including recommendations for potential participants, participation in interviews and sharing early findings for feedback. This study reports on focus groups and interviews with individuals from Maori and disability sectors.

Use of Digital COVID-19 Exposure Notifications at a Large Gathering: Survey Analysis of Public Health Conference Attendees.

BACKGROUND: WA Notify was Washington State's smartphone-based COVID-19 digital exposure notification (EN) tool, which was used to help limit the spread of COVID-19 between November 30, 2020, and May 11, 2023. Following the 2022 Washington State Public Health Association Annual Conference, attendees who had WA Notify activated began receiving ENs alerting them to a possible COVID-19 exposure during the conference. A survey was emailed to all conference attendees to measure WA Notify adoption, mechanisms through which attendees received ENs, and self-reported engagement in protective behaviors postexposure. OBJECTIVE: This study aimed to learn more about the experiences of WA Notify adopters and nonadopters who may have been exposed to COVID-19 at a large group gathering. METHODS: A web-based survey administered through REDCap (Research Electronic Data Capture; Vanderbilt University) was sent to all attendees of the Washington State Public Health Association conference. Self-reported demographic information and characteristics of respondents were summarized. Regression models were used to estimate relative risks to compare WA Notify adoption and testing behaviors between groups. RESULTS: Of the 464 total registered attendees who were sent the survey, 205 (44%) responses were received; 201 eligible attendees were included in this analysis. Of those, 149 (74%) respondents reported having WA Notify activated on their phones at the time of the conference. Among respondents with WA Notify activated, 54% (n=77) reported learning of their potential exposure from a WA Notify EN. Respondents who reported that they did not have WA Notify activated and learned of their potential exposure via the event-wide email from conference organizers were 39% less likely to test for COVID-19 compared to respondents with WA Notify activated who learned of their potential exposure from the email (relative risk 0.61, 95% CI 0.40-0.93; P=.02), and this gap was even larger when compared to respondents who learned of their exposure from a WA Notify EN. The most commonly cited reason for not having WA Notify activated was privacy concerns (n=17, 35%), followed by not wanting to receive ENs (n=6, 12%) and being unaware of WA Notify (n=5, 10%). CONCLUSIONS: Digital EN systems are an important tool to directly and anonymously notify close contacts of potential exposures and provide guidance on the next steps in a timely manner. Given the privacy concerns, there is still a need for increasing transparency surrounding EN technology to increase uptake by the public if this technology were to be used in the future to slow the spread of communicable diseases.