Scientists at the University of Otago released a suprising new study on Friday which reveals where New Zealand's early cases of coronavirus came from.
The researchers analysed the genomic sequencing of 649 people infected with COVID-19 between February 26 and May 22 - representing 56 percent of all confirmed cases during that time.
The sequences could quickly tell the team where each specific case of COVID-19 came from and pick it apart from other cases in the community.
On Friday the pre-print of the study, led by Dr Jemma Geoghegan, revealed most cases in New Zealand originated from North America rather than Asia where the virus first emerged.
They said this is "likely reflecting the high prevalence of the virus in North America during the sampling period".
They found that the 649 cases came from 277 separate introductions of the virus into New Zealand, although once here those infected were able to keep further infections under control.
The scientists estimated 24 percent of cases led to only one other secondary case while just 19 percent of those introduced cases led to a chain of transmission that could be observed as a lineage.
"The remainder (57 percent) did not lead to a transmission event."
The scientists also showed there was no sign of COVID-19 circulating in the community before New Zealand's first case was reported on March 26, a man in his 60s who'd arrived in the country from Iran.
