The paper you linked shows effectiveness of previous infection alone at 46%, 3 vaccine doses at 52% (and slightly above the upper end of the confidence interval for infection only), and previous infection and 3 doses at 77%. When I looked for earlier studies, the first one that popped up was this one from Sept 2021, which finds that previous infection gives a 90% reduced risk re-infection.
This seems to be consistent with what has been reported more popularly; in 2020-2021 it seemed that the immune benefit from a previous infection could last several months, and that this informed the timing on when boosters were recommended. Whereas now it seems it's significantly easier to be re-infected with an omicron variant relatively soon after a previous infection.
The finding of 90% in late 2021 vs <50% now does sound like the protective effect of prior infection _is_ changing.
Look a Figures 1, 2 and 4, and you'll see clearly that protection against severe disease remains quite robust. Protection against severe, critical or fatal Covid-19 due to any Omicron infection is shown at 91% (95% CI 60-100) after prior infection (Figure 2D).
> You are going to get Covid multiple times in your life, regardless of your vaccination or infection status.
Yeah but whether you expect to get it once every couple years or multiple times a year is meaningful to what living in a post-covid world looks like.
Earlier your very firm statement did not qualify the unchanged protective effect as being limited to severe, critical or fatal disease, and I think you're moving goalposts.
> The protective effect of prior infection is not uncertain, nor is it changing.
> The protective effect of prior infection is not uncertain, nor is it changing. There have been dozens of papers now, all saying the same thing: natural infection is at least as protective (if not more so) than even 3 doses of the current vaccines.
I was saying that natural infection is equivalent to vaccination -- if not better. Then, in the same comment, I explicitly said that none of this will prevent re-infection:
> Norway is saying what it is, because we know that most people -- vaccinated or previously infected -- will eventually get re-infected. But even if you are re-infected, you will be well-protected against severe illness.
Did people originally overstate the claim that vaccination would prevent infection? Absolutely. Do we now know this to be untrue? Again, absolutely. You're going to be re-infected multiple times in your life. Cannot be helped.
But it's still true that infection and vaccination offer at least equivalent levels of protection. So if you're concerned about the protection of "natural immunity" -- by whatever standard -- then I have bad news for you: the vaccines are no better.