Here is information regarding Apple's iPhone iOS 3.5 + setting regarding contact tracing for COVID-19.

Anonymous COVID-19 contact tracing via Bluetooth (not GPS location) is available with iOS 13.5.

Note: The “COVID-19 Exposure Logging” toggle is disabled by default in iOS 13.5. This does not collect any data without you installing and authorizing a local health authority app. Apple and Google’s exposure notification system is completely opt-in.

How to turn on/off COVID-19 contact tracing on iPhone

1. On iOS 13.5 and later, head to Settings on your iPhone
2. Swipe down and tap Privacy
3. Now choose Health
4.  Tap COVID-19 Exposure Logging at the top
5. For now, you’ll need an authorized app before Exposure Notifications can be turned on. But then you can tap the toggle to turn notifications on or off
6. You can also delete the exposure logs manually at any time at the bottom of the settings
7. Follow along here for when apps from health authorities become available in the U.S.

Here’s how these steps look:

Information taken from: https://9to5mac.com/2020/05/19/how-to-turn-on-off-covid-19-contact-tracing-iphone-ios/