[cperciva]

If social distancing can bring the number of cases down to a manageable level, you can switch to a traditional public health approach: Test anyone showing symptoms, and aggressively trace and test any contacts of known cases.

[fspeech]

You also need universal mask wearing. South Korea had a huge cluster, but mask wearing practice saved it from spiraling out of control.

[martokus]

Wouldn't they be afraid that if the rules are relaxed the single cases would spiral up and start it all over again?

[cperciva]

If you can identify the remaining cases and isolate them, you're fine. The danger is that some cases slip through the contact tracing procedure (e.g. the identified patient forgot about someone they were in contact with) which is why you also want to aggressively test anyone presenting with symptoms.