https://www.pbs.org/newshour/health/breakthrough-covid-infections-show-the-unvaccinated-are-now-putting-the-vaccinated-at-risk
Forget the political side.
Looks like there is very little data on "breakthrough cases" since data on vaccination does not seem to follow just testing data.
The only data that seems to be followed right now are hospitals and death, where there is a clear difference..although they also did not show if there was a variant effect either.