The Ministry of Health has failed to prepare the contact tracing system for the Delta variant, despite four critical reviews identifying gaps that remain unfilled, Marc Daalder reports
ANALYSIS: As the number of contacts associated with the Delta outbreak skyrockets past 20,000, the system is struggling to cope.
As of Wednesday morning, less than two-thirds of the 20,363 known contacts had even been “formally contacted”. Just 62 percent had returned a test result. And the list of contacts was only expected to grow.
It wasn’t until six days into the outbreak, on Monday evening, that staff from other government departments began to be seconded into the contact tracing effort. At the same time, urgent job ads went out on social media, seeking 600 tracers to work in a call centre and particularly seeking out people with Samoan language skills.
The system appears to be bursting at the seams and the Government’s only response so far has been to shrug off criticism because this outbreak is bigger than what they had prepared for.
But that ignores four stark warnings that the Government has received over the past 18 months about the state of the contact tracing system. Each of these critical reviews found that the system would struggle to handle a medium-sized outbreak. Now such an outbreak has arrived and it has been spurred on further by the fact that it involves the highly transmissible Delta variant.
The warnings
While the Ministry of Health has been receptive to some of the suggestions of previous reviews, it has pushed back on recommendations to increase both regular contact tracing capacity and surge capacity. It also appears to have greatly over-estimated its own capacity.
The April 2020 review of the contact tracing system by Ayesha Verrall – then a University of Otago epidemiologist, now a Labour MP and Associate Minister of Health with responsibility for public health – recommended the system be able to trace the contacts of 1000 new cases a day. This was one of just three “critical” findings in Verrall’s rapid audit.
Verrall was operating off of British research at the time, which found each case had an average of 36 contacts. She was in essence calling for the system to be able to trace as many as 36,000 contacts each day, envisioning how contact tracing might cope with a large-scale outbreak if elimination failed.
A follow-up to Verrall’s report from Sir Brian Roche, Otago epidemiologist Philip Hill, Warren Moetara, Dr Marion Poore and Liz Read found that there was still more work to be done. A June 2020 report from this committee recommended: “Additional resources from across the Government and potentially beyond are needed to support and assist the ministry in delivering the goal of the health system having immediate surge capacity to manage a situation with 350-500 cases per day and a pathway to cope with 1000 cases per day without reducing quality.”
When the Auckland outbreak hit, the Auckland Regional Public Health Service (ARPHS) struggled to handle the explosion in cases and contacts.
A review of contact tracing during that outbreak by Roche and Hill, conducted in November, hinted that the Ministry of Health seemed uninterested in actually reaching the 1000 cases per day benchmark.
“The main issue is that there is a disconnect between the actual/proven capacity for an outbreak and the general understanding by the Government and the public of the capacity of the system of up to 1000 cases/day,” they wrote.
Capacity within ARPHS, which was the Public Health Unit (PHU) most likely to deal with a Covid-19 outbreak, had been degraded by underfunding. It was estimated to have standing capacity to trace the contacts of 20 cases today and could surge to handling 80.
Improving capacity would have required additional funding. At the time, ARPHS had a budget of $24 million and was facing a shortfall of nearly $12 million – and this took into account a one-time funding boost of $7 million for dealing with Covid-19. In Budget 2021, the Government allocated just over $37m over four years for all of the country’s PHUs.
A December funding round from the Covid-19 Response and Recovery Fund also saw $1.12 billion earmarked for a mixture of testing, contact tracing and PPE provision. It’s unclear exactly how much went to contact tracing in particular and whether this was for PHUs or the ministry’s National Investigation and Tracing Centre. Either way, a later review found tracing capacity was still insufficient.
1000 cases/day scrapped
Despite the red flags from earlier reviews, not enough was done before the February cluster, when just 15 cases produced nearly the same number of contacts as in August – around 6000.
A subsequent review of the February response from the real-time advisory group chaired by Roche and on which Hill also sits – the most recent report to touch on contact tracing – found the Ministry of Health had all but abandoned the 1000 cases per day goal.
“Despite the previous recommendations about the Covid-19 Response System’s capacity in multiple reports, the ministry appears to have been developing advice based on the assumption that the need for capacity to surge to be able to trace the contacts of 1000 cases per day is now obsolete,” this review found.
“In our view, if one uses 10-30 close contacts per case as a guide, we agree with the previous report of September 28, 2020, which suggested that New Zealand would struggle to maintain high system performance of contact tracing for a prolonged period with 100-200 cases per day.”
In recent months, the Government has more willingly and publicly admitted that it has scrapped the 1000 cases per day target. Instead, the Ministry of Health has emphasised the number of contacts traced per day.
Verrall’s original report envisaged far fewer contacts per case than we have seen in 2021. In the February outbreak, 15 cases produced more than 6000 contacts. The Sydney man who visited Wellington for a weekend in June spawned 2500 contacts on his own.
The real-time advisory group conceded in their review of the February cluster that this was a valid approach. However, they said there was still lack of clarity about the real capacity in the system.
“The ministry has stated that it prefers to consider capacity in terms of numbers of contacts that can be traced. This is not unreasonable. However, no target capacity for the number of contacts to trace per day has been specified and the present capacity has not been clarified,” they wrote.
“We do not accept that it is unreasonable to not have clarity on the capacity of the Covid-19 Response System on the basis that it is complicated. Since the original recommendation in the Verrall report, Singapore (population 5-6 million) and Melbourne (population 5-6 million) had outbreaks that reached over 900 and 700 cases per day respectively, and Israel (population 10 million) went from very low numbers of cases to over 10,000 cases per day as recently as January 20, 2021.
“None of these outbreaks appear to have been due to new variants, which now complicate the picture further. Even if a lockdown back-up is actioned, Public Health Units (PHUs) will still have to do contact tracing around all cases of an outbreak.”
Surge capacity questioned
The review of the February cluster also reported that the Ministry of Health didn’t think surge capacity needed to be increased.
“We do not agree with the ministry’s assertion stated to us that it is not necessary to increase the standing or surge capacity in New Zealand or the assertion that this is not possible because there is a lack of an available workforce.”
On Tuesday, Ashley Bloomfield contested that part of the report.
“What I would say as the chief executive of the Ministry of Health is: that’s not a view that I did or do hold, that we didn’t need to continue to build surge capacity—and, indeed we have,” he told the Health Select Committee.
“So all of the public health units around the country who are currently involved, and have been from the start, in the contact tracing response to this outbreak, have got surge capacity and they have surged up with all that addition of surge capacity.”
Figures released by the Ministry of Health to the New Zealand Herald ahead of the Delta outbreak showed it had worked to improve capacity. The department said it had standing capacity to identify, isolate and monitor 3000 contacts a day and could surge to double that.
And yet, when faced with the latest outbreak where there have been just 2545 contacts a day, the system is struggling to cope even after standing up the reserve surge capacity, seconding staff from other government departments and seeking to hire brand-new call centre employees. In fact, just 1589 contacts have been identified and contacted a day, on average, over the outbreak – barely half of the ostensible standing capacity the Government had at the ready ahead of the outbreak.
This struggle is in line with the predictions of the review of the February cluster. It said a prolonged period involving between 1000 and 6000 contacts a day or between 7000 and 42,000 contacts a week would stress the contact tracing system.
The Delta outbreak has so far averaged 2545 contacts a day and 17,817 contacts every seven days – nearly the middle of the range in the February review.
Delta not fully prepared for
Covid-19 Response Minister Chris Hipkins says he sees no problem with the system response, which has left more than 7600 contacts of Covid-19 cases un-contacted as of Wednesday morning.
And Bloomfield has excused it by implying the system simply wasn’t prepared for the size of the Delta outbreak.
“Reflecting on the comparison with August last year, we had anticipated in our preparations for a possible Delta outbreak that there would be a higher surge, but here we’ve got 10 times the number of close contacts that we had in August last year, and, actually, at this point in the outbreak, a larger number of cases. You never know quite how many cases you’re going to get,” he told Newsroom.
Hill, one of the authors of three of the contact tracing reviews, said that the Delta outbreak is only moderately sized. It’s certainly far from the worst case scenario of thousands of community cases.
“It is important to note that this outbreak was detected relatively early, most likely within 11 days of the first case appearing in the community and it has behaved as one would have expected,” he told Newsroom.
On Wednesday, Bloomfield again referred to the size of the cluster as taking the system by surprise.
“You never know quite when you get the first case how many other cases there are at the time and, indeed, how active they may have been. We have seen – and you will see from the demographic description of this outbreak – that there are a lot of younger people. We saw that right from the start. So, that’s one thing. I’m not saying we weren’t prepared for that,” he said.
He said another reason for the capacity issues was ARPHS’ decision to liberally apply the “close contact” label. A casual contact requires only one or two calls from contact tracers, while a close contact has to be checked in on daily. Nearly all of the 20,363 contacts identified so far have been classified as close.
But this was part of the protocol for Delta that the Government was ostensibly prepared for. When asked why the capacity hadn’t been increased in light of an expected increase in the number of close contacts in a future Delta outbreak, Bloomfield said merely, “the preparation was ongoing at the time”.
Hill is less certain about that, telling Newsroom he’s seen little evidence of improvements made since the real-time advisory group’s June report.
“We previously warned in each of three previous reports since mid-2020 that New Zealand would struggle to deal with a significant outbreak if capacity wasn’t increased substantially,” he said.
“We have not seen how this has been addressed since the report submitted in early June this year.”
