Found this from Forbes
How to disable Apple and Google COVID-19 exposure notification
If you've decided, for whatever reason, that contact tracing isn't something that you want to participate in, then you'll likely be looking for ways to disable or delete the exposure notification framework.
Remember, however, if you don't enable exposure notifications, then you will not be notified if you have potentially been exposed to COVID-19. Only you alone can determine if that is a risk worth taking, and the flip of this is that you might also expose others who would be none the wiser if you had the infection.
First things first, then: you don't need to 'disable' exposure notifications as they are not enabled by default. As I've already made clear, the exposure notification framework currently only works if you have installed an official tracking app and opted into using the notification system. Even if, or when, it becomes part of the operating system without the need for a separately installed app, it will still be an opt-in thing.
Google said that you can
turn off exposure notifications in your Android phone settings or uninstall the official public health app if you've previously installed one when it becomes available. Just go to the settings app, click on Google|COVID-19 exposure notifications, and you can toggle them on or off from there. From the same place, you can also delete any random IDs that have been stored by clicking on Delete random IDs|Delete.
Apple said that the "choice to use this technology rests with the user, and he or she can turn it off at any time by uninstalling the contact tracing application
or turning off exposure notification in Settings." As with Android users, the toggle for exposure logging is off by default in iOS 13.5 and later. If you have installed an officially authorized app and opted into exposure notification use, then you need to go to Settings|Privacy|Health from where you can toggle them on or off. You can also delete any exposure logs, kept for 14 days as with Android devices, from the same settings page.
Remember, in both cases, you won't be notified if you've been exposed to COVID-19.