If you start from the premise that a much larger portion of the vulnerable in the US have already been infected, the expectation would be that the gap will only ever narrow, so the direction isn't really an indictment of the policy in Australia, you have to look at where things end up.

I didn't say it was an indictment of Australian policy, and don't think that. But my parent was saying that the gap was unlikely to narrow, which is just wrong.

Besides the statistical anomaly at the end (probably a one time correction for some past cases) the US death rate has always been higher. So the gap has been widening until now. Look at cumulative cases.

Only the derivative of the gap, the daily deaths per capita, has been narrowing. I agree that the daily numbers should become similar when prior immunity due to vaccination or infection becomes similar (all else being equal). But that does not erase the huge amount of deaths before people got their first vaccine.

Good point! In cumulative deaths per million:

                  US   AUS  delta
    2022-01-01  2477    87   2360
    2022-02-01  2673   141   2532
    2022-03-01  2852   204   2648
    2022-04-01  2948   247   2701

I didn't look closely at the graph and I misread the recent apparent spike, which I agree with you is likely some kind of correction.

I'm sorry I can't go back and edit my comment!