The original hope was that vaccinated people wouldn't get it at all, as per any other vaccine. Delta proved for this to not to be the case, unfortunately.
> The original hope was that vaccinated people wouldn't get it at all, as per any other vaccine
This is false. No vaccine provides 100% protection. Even MMR, one of the most battle-tested vaccine provides ~97% protection against measles and ~88% against mumps.
If you get higher than 70% efficacy then it's usually considered very helpful for public health. Last year, we were not even sure if we can get 50% efficacy (a borderline for approval) but it turns out that COVID vaccines are so effective that it even works reasonably well for variants, with a caveat of diminishing effects over time.
>it turns out that COVID vaccines are so effective that it even works reasonably well for variants
As per this CDC[1] report - "Two doses of mRNA vaccines were 74.7% effective against infection among nursing home residents early in the vaccination program (March–May 2021). During June–July 2021, when B.1.617.2 (Delta) variant circulation predominated, effectiveness declined significantly to 53.1%."
Exactly as I originally commented and you deemed false, due to the Delta variant, we observed an efficacy level (53.1%) considerably lower than any other modern vaccines. I'm not sure what's controversial about the statement that it's obvious that the COVID vaccines are unforunately not working nearly as well as we were originally told that they would.
Vaccine efficacy on the Delta variant is still a debatable topic, and it's dangerous to make any conclusion from a single reference limited to a very specific, narrow subset of sample.
You probably remember Israel's report (which is strongly motivated to promote booster shots) indicated that vaccine's efficacy was pretty low, but it turns out to be a textbook case of Simpson's paradox[1] from extremely biased vaccination rate.
From what I saw from KDCA's daily reports (which performs extensive contact tracing with a pretty high coverage, not even remotely comparable to the US), it's more of 70% protection against Delta. Though it's possible that its efficacy is waning over time, which may explain the gap between Korea and Israel.
