SHORT OF TARGET

WELLINGTON: contact tracing efforts for at least two of the eight border incursions since the end of July were well below the gold standard the Government expects.

The gold standard is to reach 80% of case contacts within 48 hours of a positive case being returned, but for the August cluster only 60% were reached in that timeframe.

The Ministry of Health said the reasons included learning about potential exposure events late.

The effectiveness of contact tracing often depends on how much detail a case can recall and verifying that independently, if possible.

Faster contact tracing could have helped contain the cluster more quickly.

It ended up with 179 cases, including three deaths.

The cluster also involved people who initially questioned if Covid19 was real.

The ministry would not say how many close contacts overall there were in this, or any other of the border incursions, despite having previously provided such information.

For the Christchurch returnees who left managed isolation while still incubating the virus, only 51% of contacts were reached within 48 hours.

Transmission in that small outbreak of six people — three recent returnees and three household contacts — is thought to have happened via a shared rubbishbin lid.

A returnee tested negative before leaving managed isolation, then infected someone on a chartered flight from Christchurch to Auckland.

As was the case with the cluster, the ministry said there were delays in finding out about places visited by potentially infectious people.

“This was a result of a complex web of contacts which were progressively revealed over time from the inbound flights to New Zealand, the managed isolation facility, and the flight to Auckland as the investigation continued,” the ministry spokesman said.

One of the infected families travelled to Taupo, where they met 18 others from five locations around New Zealand. Some went to the hot pools. Others went skydiving.

The ministry noted that several agencies across New Zealand were involved in the contact tracing process, given that those involved had travelled around the North Island.

The ministry provided data for only three other border incursions, citing privacy reasons.

It would not explain how providing a percentage figure about contact tracing for a known case could potentially breach someone’s privacy.

Contact tracers were able to reach all of the contacts within 48 hours for each of the two Sudima Hotel nurses who caught Covid19 while treating infected mariners from Russia and Ukraine.

For the Defence Force cluster, which has six cases including at least three Defence Force staff, 97% of the contacts were reached within 48 hours.

“Despite a complex setting, performance against the target has been achieved through intensive tracing efforts,” the ministry said. — The New Zealand Herald