South Korea has paused its gradual return to normal scheme and introduced stricter virus prevention measures.
The biggest change applies to social gatherings.
In the capital region, groups of up to six people will be allowed.
Eight can meet elsewhere.
One unvaccinated person per group is permitted.
Vaccine passes are now required in restaurants, cafes, theaters and cram schools.
Visitors must show proof of vaccination or submit a negative PCR test taken within the previous two days.
A one-week grace period is in place.