[makomk]

South Korea has been demonstrating the limits of contact tracing for a while - "looking for one’s lost keys under the glow of a streetlight" is about right - but you wouldn't get that impression from the coverage in western media, which seems more interested in pushing a narrative than anything else. The percentage of cases that aren't linked to any existing case just keeps on going up, even though they really don't have any way to detect those cases reliably, and they rely on the same kind of large-scale social distancing and business closures as countries with less extensive contact tracing even though most people probably have the opposite impression. (Every time they loosen those restrictions cases keep going up, which doesn't stop them from repeatedly attempting to anyway.)

It was definitely worth trying in the early days of the epidemic, and almost every country did so with reasonable success initially - even the US, not that you'd know that from the media coverage unless you paid close attention - but once Covid is endemic and there's a bunch of unknown, undetected cases contact tracing seems to lose a lot of its power.

[pmkiwi]

Of course if the outbreak becomes out of control, the efficiency of contact tracing is severly lowered. But even if the % of people linked to a cluster via contact tracing is low, it still has real value. If you couple it with genomics sequencing and pool testing, contact tracing (long) chains of transmission and help (re)directing resources where the cases truly are.

[cameldrv]

It's working extremely well compared to the U.S. The death rate in S. Korea is 37/1,000,000, one of the lowest in the world. In the U.S. it's 1,797/1,000,000. That's 48x better than the U.S. I'd say whatever they're doing is working even if it isn't absolutely perfect.