Basically the same as now. People coming in from abroad quarantine for 14 days. Whenever there's a case, they trace and test everyone they've been in contact with, and also the second degree contacts. For one case, they tested more than 10,000 people, off memory.

You're exactly right. Even these measures do not work to contain omicron. The only thing that's changed over the past two years is that the new strain is so much more contagious.