That certainly helped, but we had infections cross the border and community transmission. We still have people entering the country through a 14 day hotel quarantine so we're still allowing infected people across the border into the country. The island nation part of it isn't the whole story.

Restricting the rate at which it can spread through the community coupled with active and aggressive contact tracing certainly seems like it played a significant role. I'd be looking cockeyed at any study that chooses not to include the Australian and NZ datasets without a very robust case about why it's necessary.