An audit of New Zealand’s contact-tracing systems found the units were its main weakness, and recommended they urgently be expanded with extra staff to help isolate possible cases.
It also found that the national service set up to help the regional units was initially working too slowly, partly because it could not find phone numbers for people or people chose not to answer calls from an unidentified number.
In response, the Government has allocated an extra $55 million to the 12 public health units (PHUs) so they can expand as required.
The national centre will also begin sending text messages if calls are missed.
Prime Minister Jacinda Ardern said yesterday that having to suddenly scale up from a regional to a national system had been a huge ask for the public health teams.
‘‘There is more to do, though, and we’re very, very open about that.’’
Contact tracing is the identification and isolation of people who have been exposed to an infectious case, to prevent onward transmission from the contact to others.
Combined with other basic public health measures, it has more than 90% efficacy against Covid-19 at the population level, making it as effective as many vaccines.
It is part of the normal work of PHUs, as partof tracking diseases such as measles or vaccines.
The contact tracing audit, completed last Saturday by University of Otago infectious diseases physician Ayesha Verrall, found although work had already begun to upscale New Zealand’s contact-tracing ability, it was not enough.
Dr Verrall recommended the Ministry of Health expand the capacity of PHUs to isolate Covid-19 cases and trace their contacts ‘‘three to fourfold’’ for as long as the virus remained a public health threat.
Some of that additional capacity should include contact tracing teams that could move from one regional unit to another according to need, she said.
Dr Verrall praised the rapid development of a national close contact service hub (NCCS), which began operating on March 24, together with anew technology system designed to help with contact tracing.
However, she said despite support from the national system, PHUs were still at or beyond their capacity to manage cases and contacts when lockdown was introduced on March 25, because the system was only being used in a narrow set of circumstances.
Even if changes to the way those two services interacted were made — which will happen —Dr Verrall said the national service was not as suitable or desirable system for managing all contacts.
‘‘The NCCS also has limited use in certain important situations, such as in the event of a large complex cluster or specific scenarios that require intense involvement of medical officers of health,’’ she said.
The NCCS was also struggling with timeliness at that stage, with issues such as a lack of contact details in the National Health Index for some cases, and people not answering their phones because the call was from a strange, four-digit number.
Therefore, Dr Verrall recommended the MOH develop a plan that not only included how to rapidly scale case identification, but also specified taskshifting arrangements between PHUs and NCCS.
She said between them, the system needed to manage up to 1000 cases a day while maintaining high performance.
Dr Verrall gave asuite of other performance indicators that needed to be met, including the need to have 80% of contacts of a Covid-19 case quarantined within four days.
At the time of her report, the MOHand local developers were building a smartphone app to assist with contact tracing, she said, but as it was not completed itcould not be meaningfully evaluated.
Director-general of health Ashley Bloomfield said yesterday up to 5000 contacts aday could be traced at present, and the capacity would continue to be built so it could be scaled up rapidly.
Minister of Health David Clark said the funding meant PHUs would be expanded, with additional surge capacity of up to 300 full-time-equivalent staff.
The NCCS would also get extra resources to manage complex investigations such as detailed analysis of clusters.
Dr Clark would appoint an expert group to advise on progress. The new technology system — the National Contact Tracing Solution —would be developed further and future-proofed so that it could manage the delivery of a Covid-19 vaccine when one became available, he said.
