First, the Harbin outbreak is claimed to have been triggered by return migration, and detected at the level of dozens of cases.
archive.is/LBKzy
We can guess that it likely involves China's digital quarantine, which uses WeChat and Alipay to give every citizen routinely updated red/yellow/green color codes.
archive.is/gDgfb#selectio…
They could push the app it to all Android & iOS devices. Though keeping it up-to-date with accurate data is nontrivial. As is doing it in a privacy preserving way.
- vaccine equivalent
- government permission
- solvent businesses
- unchanged preferences
- no internet-based alternatives
- fast vaccine updates
- high disposable income