I believe the Covid-19 Data Store is already something close to this, and it’s also what Palantir have built for the NHS - in a “you give us data, we’ll build the thing for £1” deal, which was probably a bad deal as the data was infinitely more valuable than the modelling AI. And the NHS version is that you can “zoom in” to the individual healthcare details - they claim this is needed.
I’d rather not have it, personally.
Maybe I’d feel differently if I had experienced or was experiencing a rare disease that doctors needed to share knowledge on to figure out how to treat it, but I’m not and I believe that the line of “data sharing helps the NHS provide you with better care” is mostly nonsense as run-of-the-mill stuff isn’t treated any differently.
If you break your leg, you will be referred to a hospital for an X-ray on the leg and to get a cast. It’s not rocket science for that to be done, and no extra insight is going to be gained from the hospital being able to see that you had a bout of pneumonia in 2007.