The Ministry of Health said in a statement this afternoon, the person arrived from Singapore on October 31 and has been transferred to the Auckland quarantine facility.
Twenty-four previously reported cases are now considered to have recovered, bringing our total number of active cases to 44.
The total number of confirmed cases now stands at 1618.
Yesterday laboratories completed 6856 tests for Covid-19, bringing the total number of tests completed to date to 1,126,986.
Cases linked to managed isolation in Christchurch
Since identifying the positive test results in the two people who work in the managed isolation facility at the Sudima at Christchurch Airport, the ministry said its systems had rapidly worked to put a ring around the virus and stop it spreading in the community.
The first health care worker reported as testing positive sought a test quickly after developing very mild symptoms, even though they had just been tested two days earlier. This swift action allowed for the rapid isolation of Case A and trace and test their contacts, it said.
The ministry then identified a further positive case in another health care worker, Case B, and quickly traced and tested their contacts.
Widespread testing has taken place in the managed isolation facility and in the contacts of the two health care workers.
Staff who worked at the Sudima Hotel since October 23 have been tested, with all 193 returning negative results.
All of Case A’s close contacts have returned a negative result, and all results received from Case B’s close contacts are negative to date, with one result outstanding.
Investigations are continuing to determine when exactly the health care workers were exposed to the virus, but the ministry believes them to have been infected by the international mariners they have been caring for, 31 of whom have tested positive for Covid-19.
The genome of Case A is B1.1.7 – of the international mariners who have tested positive for Covid-19, five are part of the B1.1.7 lineage.
Case A’s genome is an exact match with the genomes from these five mariners, indicating a high likelihood that one of these guests is the source of the health care worker’s infection. The ministry was awaiting genome sequencing results for Case B.
The ministry said health care workers wore personal protection equipment while conducting their work, "but we know this virus is tricky and has thwarted our systems before".
The ministry said a review would be carried out at the managed isolation facility at the Sudima to assess where procedures could be improved to prevent similar infections in the future.
"These reviews have taken place at other managed isolation facilities and are part of our approach to continually improve how we manage Covid-19."
The Community and Public Health team in Christchurch has conducted detailed investigations including interviews and contact tracing and we are confident that there is only an extremely low risk of re-exposure from the health care workers to the mariners, it said.
The Community and Public Health team is working on an exit plan for the mariners, who will be transferred directly onto their ships once released from managed isolation.
"The system here has worked as it is intended to. It is a reminder that we need anyone who develops symptoms of Covid-19 to act with haste in seeking advice on getting a test. The quick-thinking from the health care worker has allowed us to stop this virus spreading into a larger outbreak."
