By Bronwyn Howell
New Zealand has attracted a lot of international attention during the COVID-19 pandemic due to the apparent success of its virus elimination strategy, which keeps its infection and death rates low. However, this has come at the cost of the world’s strictest lockdowns when community infections are detected, along with draconian border policies – even for New Zealand citizens.
Unfortunately, the delta variant has proved too difficult to soften New Zealand’s acclaimed elimination strategy. A single case discovered in Auckland in August has grown into widespread community infections. New cases continue to rise, mainly in Auckland, but are spreading to neighboring regions, with the current daily national average approaching 200. Elimination has been abandoned in favor of containment, as observed in almost all other countries. When all health districts across the country achieve vaccination coverage of 90 percent of the eligible population over the age of 16, the country will transition from its existing lockdown system to a new “traffic light” system based on projected demand for local populations. healthcare resources, given the magnitude of community transfer in each relevant area.
For all traffic light colors (green, orange and red), the restrictions for vaccinated persons are much less severe than those for non-vaccinated persons. The key to the transition to the new system is the availability of vaccination certificates (end of November). Regardless of the color of the traffic light, however, it is mandatory for all businesses and individuals to track their activities using the NZ COVID Tracer (NZCT) smartphone app or other systems (e.g. paper records). This is a continuation of a mandate from COVID-19 Minister Chris Hipkins (who took effect on Sept. 7) that requires building operators and event hosts to ensure that individuals comply with the requirement to scan or identify other personal information. which allows tracing contacts in the event their premises are identified as a possible site of infection transmission.
NZCT differs from most other contact tracing apps on smartphones (e.g. Apple/Google Bluetooth app) in that users need to scan QR codes when entering buildings or public transport vehicles. Scanning is a tricky but visible activity, which can verify that the activity has taken place. However, monitoring and enforcement are costly, so it mostly relies on individual self-motivation or peer pressure to scan. The most interesting feature of NZCT use when it was voluntary was the extent to which scanning was not is done by registered app users. To that end, it is interesting to see how the app usage has changed according to the instruction mandating its use.
While more than 3.3 million apps were downloaded (about 66 percent of the population), on average less than 20 percent of registered applications registered a scan on any given day prior to the Sept. 7 mandate, although this increased when local infections were discovered. notified in August 2020 and February 2021 (Figure 1). The number of active devices on any given day increased immediately after the mandate, but it was still observed that only about 35 percent of apps were scanning. This was lower than the peak in August 2020 when 50 percent of apps were active. The mandate has led to an increase in the number of app users taking scans, but many app users still don’t scan on a daily basis.
In contrast, the proportion of apps that activate an optional Bluetooth feature does not fluctuate with infection outbreaks. This rose from 50 percent of registered apps to 68 percent, but the increase appears to have coincided with local outbreaks (Aug. 18, when the risk of infection increased), not the application usage mandate on Sept. 7.
Scan activity has certainly increased after the mandate: from 500,000 scans per day in early August to 2.5 million (but declining) in September (Figure 2). This seems to be caused by the mandate and not increased risk of infection; there was a negligible increase when the outbreak was identified in August.
However, Figure 3 shows that the average number of scans per active app did not increase much after the authorization. Most additional scanning activity comes from inactive users who have become active. For the most part, active users scanned just under two codes per day on average (with negligible change despite local viral spread until the August 2021 outbreak, when the strictest lockdown restricted most activity). After the mandate, only 2.2 scans per active device were registered. This suggests that even the most avid scanners don’t scan much, and the mandate hasn’t changed that.
It remains to be seen whether even these low activity levels can be maintained if the “traffic light” system is embedded. However, as the number of active devices and the number of scans are declining (albeit at a slower pace than before), it appears that, despite Hipkins’ mandate, the high costs of scanning, monitoring and enforcement will continue to pose significant limitations to their use and eventual outcome. success of NZCT.