An investigation into how a worker at a managed isolation facility contracted COVID-19 has concluded transmission occurred in an elevator.
The Director-General of Health announced the "mystery" case on August 18, a maintenance worker at the Rydges hotel in Auckland had tested positive.
Genome sequencing of the man's case found it was linked to a returnee who arrived in New Zealand from the United States. This person stayed at the Rydges hotel in July before testing positive for the virus.
In August Dr Bloomfield said the two possibilities for how the employee contracted COVID-19 were: human-to-human transmission, or through environmental contamination where the virus lives on a surface.
During Wednesday's COVID-19 update, Dr Bloomfield revealed the results of the investigation into the case.
"The investigation on this has now closed and concludes that the most likely source of infection was a one-off exposure event," he said.
"It's surface transmission in an elevator that the worker used after a returnee from the USA who tested positive for COVID-19 is the most likely route of transmission."
He said widespread testing had occured around the worker's household and workplace contacts to see if he could have contracted the virus from them.
"[It] did not find any other cases of COVID-19 and all tested negative and all had negative serology which suggests they weren't earlier cases who passed it on to him."
Dr Bloomfield also thanked staff and management at Rydges hotel for their support with the investigation.
"It is a complex process and it's success relies on engagement and cooperation from the case's contacts and their employers and I do want to thank them again for their support and completing that investigation."
New Zealand recorded six new cases of COVID-19 on Wednesday, all of which were in the community and linked to the Mt Roskill Evangelical Fellowship Church sub-cluster.
There are now 14 cases linked to this new sub-cluster.
The Ministry of Health is now asking all members of the church and their contacts to be tested or re-tested - even if they have no symptoms.
