New Zealand is the size of California, yet the population of Oregon. It's basically rural and not unlike Oregon in density.
Most "large" cities there are under 500,000 except Auckland (1.5 million)
Entire state of Oregon has 148 deaths "designated" as COVID-19. Majority in Portland area. Does not have closed borders.
Many other states in USA have even less total deaths.
New Zealand is an very isolated island nation. Much easier to keep outsiders away, similar to way Hawaii can. Hawaii has 17 total deaths, but Kauai now has 37% unemployment. Think many low income will be staying?