[Nokinside]

You can't top mitigation/supression until there is herd immunity.

You can get the immunity only two ways 1) enough people have been gone trough the disease or 2) vaccination.

South Korea must use mitigation/supression until they have enough people vaccinated or it flares up again. Complete eradication without immunity is not feasible unless you isolate whole country from the rest of the world permanently.

[daveFNbuck]

You don't have to completely isolate the country from the world. You just have to do testing and quarantining to ensure that infectious people and things aren't entering the country.

[yfzhou]

China has been doing mandatory 14-day hotel quarantine for all foreign arrivals like this: https://twitter.com/nishantsharma87/status/12424610259510845...

However, the latest cluster in Heilongjiang involved an asymptomatic student returned from USA, completed 14 day quarantine, tested negative before and after, but still went on to infect her family and neighbors who infected more at the hospital. Total confirmed cases in this cluster is ~50 right now.

Most of the spread in this case happened because of negligence in the hospital thinking coronavirus is eradicated there so they didn’t take precautions. Coastal cities like Shanghai are taking good measures so there hasn’t been a problem despite it being where most international flights land and basically 100% back to work for over a month now. The biggest danger is people becoming tired of wearing masks and avoiding gatherings over time.

[greedo]

The simplest explanation would be that the student was infected after quarantine.

[alisonatwork]

I agree, but that would bust the narrative that there are no local carriers any more, only "imported cases".

[Nokinside]

That's true but it's very hard to keep the system 100% tight. Governments can't prevent human trade or drug trade either.

Just something like 1 infected entering per day or week means that you must keep up suppressing and tracing.

[PeterisP]

Sure, but keeping up testing, contact tracing and other South Korea-style suppression measures is no big deal compared to the severe restrictions most other countries have had to implement. It's very troubling to shut down the economy for a whole year, but it's certainly plausible to sustain those measures until a vaccine is ready.

[SpicyLemonZest]

You can still trade with the rest of the world - people are still doing that now, in fact, with international trade being universally exempted from travel bans. But I can't imagine tourism or business travel being compatible with the level of quarantine required to keep an endemic respiratory virus eradicated within your borders.