Since Google and Apple made changes to Android and iPhone operating systems to facilitate digital contact tracing, many countries have been developing Bluetooth-based apps. Despite serious doubts about their accuracy and efficiency, these apps could still help control the Covid-19 epidemic by providing users with risk evaluations of infection and with recommendations.
Firstly, make a set of criteria for daily evaluation, such as,
1. How many contacts has the user made?
2. How much time has the user spent with the contacts?
3. How many places has the user visited?
4. How many symptoms of Covid-19 has the user developed? The app should provide a list of symptoms for self-reporting when the user feels unwell.
5. How many contacts have developed the symptoms?
6. How many contacts have been confirmed with the virus? And etc.
If the user meets any of these criteria today, a certain number of risk points is given by the app based on the degree of a criterion.
Secondly, total up today’s risk points and then add the total to a final score which is cumulative.
Finally, if the final score reaches certain levels, the app recommends that the user should take fewer social activities or be quarantined or get a PCR test. If the test is negative, the final score is reset to zero.
