Also they have some immunity to build up that we have had over the last 2 years. I know it doesn't prevent covid but it does seem to reduce it's severity a lot.
That's what I heard too, so it's a catch-22. Similar issues in Sweden in the beginning of the year when they introduced the rule that the whole household has to quarantine if only one person tests positive, suddenly the whole country was on sick leave, including the hospital staff, so they also did a DDoS on their own health care system.
During the same time there are around 5k cases with symptoms, as i understand all confirmed with a chest x-ray scan(?). Those go into the covid hospitals, which are now overflowing.
Do all of those need to go to a hospital? I don't know. But on the pictures you see mostly elderly people, and the vaccination rate among those is about as high as in HK