Some contract tracing apps have been developed with privacy built-in right from the start, for example the "official" German one recommended by the German government [1].
The technical means exist that data can be collected decentralised in such a way that only in case of an infection, with consent of the persons involved, information is passed on to others.
[1] https://www.dw.com/en/german-covid-19-warning-app-wins-on-us...
On one hand, the app, its supporting infrastructure, and the open source process by which those have been developed and documented has been exemplary and could serve as a template for similar public projects.
The implementation and operating costs admittedly are quite excessive and there hasn't been a proper RFQ process but given the urgency of the matter I'm willing to file that under minor points of criticism.
However, there's been an excessive focus on privacy and almost privacy alone to the detriment of the app's actual purpose.
If privacy rules had been relaxed in order to, for example, allow health authorities to access personal information and additional location data that would've made tracing contacts much easier and much more effective.
It's absurd that while right now civil rights are restricted, sometimes severely so, and for the most part people seem to accept that, there's an almost religious adherence to dogma when it comes to privacy.
But in this situation, the data is being used for a lot of good, i.e. keeping people safe, so they're on the ethical level of CCTVs and dashcams.