Defining Key Performance Indicators for the California COVID-19 Exposure Notification System (CA Notify)

Aronoff‐Spencer, Eliah; Nebeker, Camille; Wenzel, Alexander T.; Nguyen, Kevin; Kunowski, Rachel; Zhu, Mingjia; Adamos, Gary; Goyal, Ravi; Mazrouee, Sepideh; Reyes, Aaron; May, Nicole; Howard, Holly; Longhurst, Chris; Malekinejad, Mohsen

doi:10.1177/00333549221129354

Cited by 6 publications

(12 citation statements)

References 18 publications

(26 reference statements)

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“…The SimAEN modeling tool allows public health authorities to forecast the expected effect that implementing exposure notification could have on the effective reproduction number in their jurisdiction. 43 The convenience sample of exposure notification users in Washington State 44 and the key performance indicators from California 29 confirmed the expectation that this technology was nearly always more timely than conventional contact tracing. Respondents in Washington State also provided the helpful insight that 84% of notified close contacts were more likely to self-monitor for COVID-19 symptoms after receiving a notification, although only 39% of close contacts reported staying home while awaiting test results.…”

Section: Effectiveness and Evaluationmentioning

confidence: 61%

“…27,28 In California, which had the highest public uptake of this technology, app users anonymously notified their potential contacts a median of 4 days after COVID-19 symptom onset or diagnostic testing date. 29 In one state that chose not to offer exposure notification to the public, a university developed its own on-campus proximity technology smartphone app for the 2020-2021 academic year. 30…”

Section: Novel Digital Toolsmentioning

confidence: 99%

“…11,42 Measuring the effectiveness of exposure notification is even more challenging. As multiple authors in this supplemental issue point out, 27,29,43,44 the anonymity features of this technology preclude assessment of the degree to which smartphone app users are representative of the underlying population giving rise to COVID-19 cases, how consistently they choose to notify potential contacts of a positive test result through the app, and whether contacts became more likely to stay home, seek testing, wear face masks, or otherwise change behavior upon receiving such a notification. The SimAEN modeling tool allows public health authorities to forecast the expected effect that implementing exposure notification could have on the effective reproduction number in their jurisdiction.…”

Section: Effectiveness and Evaluationmentioning

confidence: 99%

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Innovative Approaches to COVID-19 Case Investigation and Contact Tracing

et al. 2022

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Until COVID-19, the greatest national public health crisis was the 1918 influenza pandemic, which was covered extensively by Public Health Reports. [1][2][3][4][5][6] Extrapolating from their knowledge of tuberculosis, public health authorities at that time exhorted ill people to remain home to break the chain of respiratory transmission. 7 Other contemporaneous appeals that reverberate a century later include "avoid needless crowding," "stay in the open air," "wear a gauze mask over the nose and mouth," and "keep away from houses where there are influenza cases." 2 In 2020, COVID-19 spurred case investigation and contact tracing at levels never seen in the United States. [8][9][10][11][12] Until vaccines, therapeutics, and SARS-CoV-2 tests became available, mitigation measures were strictly nonpharmaceutical. These included physical distancing, wearing face masks, and enhancing ventilation. In this context, state, tribal, local, and territorial health departments relied on asking people with COVID-19 to isolate and share information about close contacts (ie, case investigation) so that exposed people could be notified and asked to quarantine, ideally before they themselves became infectious (ie, contact tracing). [13][14][15][16][17] This supplemental issue of Public Health Reports provides firsthand examples of how public health departments across the United States reprioritized workflow and redirected staff to accommodate fluctuating COVID-19 incidence during 2020-2021, incorporated new partners to augment case investigation and contact tracing, evolved processes to improve outreach to disproportionately affected community groups, used digital tools for case and contact management and for proximity technology or exposure notification, and evaluated the effectiveness of these innovative strategies.

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Section: Effectiveness and Evaluationmentioning

confidence: 61%

Section: Novel Digital Toolsmentioning

confidence: 99%

Section: Effectiveness and Evaluationmentioning

confidence: 99%

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Innovative Approaches to COVID-19 Case Investigation and Contact Tracing

et al. 2022

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“…App uptake was similar amongst cases and contacts at 46% (CI: 44–48%) and 45% (CI: 39–51%), respectively, corresponding with the 48.7% of respondents intending to use the app in a Belgian study prior to its launch and the 46% of Belgian smartphone owners who downloaded the app by October 2022 45 , 46 . This was a high proportion compared to other countries which had well-established DPT apps 13 , 17 , 37 , 40 , 41 .…”

Section: Discussionmentioning

confidence: 86%

Individual level analysis of digital proximity tracing for COVID-19 in Belgium highlights major bottlenecks

Geenen,

Raymenants,

Gorissen

et al. 2023

Nat Commun

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To complement labour-intensive conventional contact tracing, digital proximity tracing was implemented widely during the COVID-19 pandemic. However, the privacy-centred design of the dominant Google-Apple exposure notification framework has hindered assessment of its effectiveness. Between October 2021 and January 2022, we systematically collected app use and notification receipt data within a test and trace programme targeting around 50,000 university students in Leuven, Belgium. Due to low success rates in each studied step of the digital notification cascade, only 4.3% of exposed contacts (CI: 2.8-6.1%) received such notifications, resulting in 10 times more cases detected through conventional contact tracing. Moreover, the infection risk of digitally traced contacts (5.0%; CI: 3.0–7.7%) was lower than that of conventionally traced non-app users (9.8%; CI: 8.8-10.7%; p = 0.002). Contrary to common perception as near instantaneous, there was a 1.2-day delay (CI: 0.6–2.2) between case PCR result and digital contact notification. These results highlight major limitations of a digital proximity tracing system based on the dominant framework.

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“…Previous research has primarily focused on the public uptake of these technologies [3], including New Zealand (NZ) [4][5][6]. To our knowledge, assessments of effectiveness have focused on the Bluetooth Exposure Notification Framework (ENF) [7][8][9][10][11][12][13][14][15][16][17], while there appear to be limited assessments of the effectiveness of the location-based QR code systems [18], with no assessments in the Western Pacific Region [3].…”

Section: Introductionmentioning

confidence: 99%

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

Chambers,

Anglemyer,

Chen

et al. 2024

Epidemiol. Infect.

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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 Māori 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. Key result• Public uptake and participation in the quick response (QR) code system were high (45%).• Ethnicity and contact tracing organizational level were the main predictors of whether location tokens were generated for cases. • Public health official uptake of the QR code system was suboptimal (only 15% of cases with data utilized by Public Health Units (PHUs)). • The positive predictive value (PPV) of the QR code system for identifying close contacts was close to nil but close to 100% for identifying casual contacts. Active consumer participation in the QR code system was closely correlated with perceived COVID-19 risk in the community.

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Defining Key Performance Indicators for the California COVID-19 Exposure Notification System (CA Notify)

Cited by 6 publications

References 18 publications

Innovative Approaches to COVID-19 Case Investigation and Contact Tracing

Innovative Approaches to COVID-19 Case Investigation and Contact Tracing

Individual level analysis of digital proximity tracing for COVID-19 in Belgium highlights major bottlenecks

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

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