Dr Ashley Bloomfield says he hasn’t advised the Government to put Christchurch in lockdown despite two Covid-19 cases being detected in the city because there weren’t yet indications of widespread transmission.
On Thursday morning, the Ministry of Health confirmed two positive cases were found in a single household in Bishopdale. One of the cases had travelled to Auckland to provide childcare.
The Director-General of Health said at least one of the cases was symptomatic in Christchurch from October 18.
The pair, both unvaccinated, also visited two households on October 19 and 20. Nine close contacts over three households identified so far from these exposure events.
"There were people there who were from a couple of other households ... they are the only close contacts that have been identified because after that they were both feeling quite unwell and laid low at home,” Bloomfield said.
"That's why one of the key inputs into our advice, at this stage, about the need not to go up an alert level is that the number of close contacts is relatively small, they know who they are, and they're being tested and isolated."
Bloomfield added he didn’t believe there were a “reasonable number” of cases in Christchurch based on negative wastewater testing on Tuesday.
To consider triggering a lockdown in Christchurch, health authorities would see if any of the close contacts of the cases test positive for Covid-19, he said.
“Our experience from the Auckland outbreak is that it’s the households and close contacts who are most likely to be infected,” he said.
“Wastewater testing will also be material here.
“But, at this stage, we have two cases, we know exactly where the origin is from, there are no large exposure events, which is material.
“So, we will be watching carefully the results of those close contacts and wastewater testing.”
Bloomfield said the test results for close contacts were expected on Thursday afternoon.
Authorities were also considering vaccination rates in Christchurch, as high vaccination rates in Auckland and Waikato had helped slow down spread, he said.
Ministry of Health data shows 69 per cent of eligible people are fully vaccinated against Covid-19 in Canterbury DHB, and 89 per cent have had at least one dose.