Table 1.
Potential DCTA technologies and the implications of their use.
| DCTAa technology | Bluetooth LEb | GPS-enabled geolocation tracking | Bluetooth LE and ultrasound | Ultra-wideband |
| Accuracyc | Accuracy reported as 72%d (distance threshold not reported) and 79% (distance threshold 1.5 m); although, independent studies did not reproduce these results [70,147,185]. | Accurate to within 4.9 m, but concerns that GPS location tracking for COVID-19 contact tracing not feasible due to limited accuracy [149,191] | Accuracy reported as 55% (distance threshold ≤6 foot) and accuracy reported as 99.6% (distance threshold ≤12 foot) [130] | Highly accurate [143] |
| Effectiveness in augmenting manual contact tracing | Limited evidence to suggest effectiveness [150,151] | Limited anecdotal evidence to suggest effectiveness [25,138] | Insufficient evidence found to suggest effectiveness | No instances of ultra-wideband–enabled DCTAs found in the literature. |
| Energy use | Less than GPS [148] | More than Bluetooth LE [148] | Not reported | Low energy use [143] |
| Accessibility and availability | Widely available [119,120] | Widely available [120] | Widely available but less so than Bluetooth LE or GPS | Not widely available [143,183,184] |
| Adherence with principle of privacy preservation | Highly adherent (records only proximity) | Less adherent (records location, which is potentially identifiable) | Adherente (records only proximity) | Highly adherent [143] (records only proximity). |
| Adherence with principles of data protection | Adherent | Interferes with the principle of data minimization | Adherent | Adherent |
aDCTA: digital contact tracing app.
bLE: Low Energy.
c(True positives + true negatives) / total number of tests.
dCOVID Tracker Ireland reported being able to accurately identify 72% of close contacts, although field studies supporting this claim have not been published.