Covid Coronavirus 19: Derek Cheng – Covid’s data problem hinders Jacinda Ardern’s big call on Monday

COMMENTARY

According to Jacinda Ardern, the key for the country to go to the national confinement with few or no complaints was “to share all the information”.

With this knowledge, the public is more inclined to trust the Prime Minister and follow meekly wherever he leads them.

So, as people start to get itchy locking feet before the Cabinet decision on Monday, you would think there would be a concerted effort to give us the most complete picture of Covid-19 possible.

But we are still in the dark about many questions that the Covid data should be able to answer, raising the question: will the cabinet’s big decision be affected equally?

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The crux of the matter is articulated in a blog by public health experts from the University of Otago: “It is still unclear on the website of the Ministry of Health as to the extent to which new Covid-19 cases in last 24 hours or last week … has no known source. “

The Ministry has duly informed us every day of the number of new cases, including the good news that there have been no new cases in the past two days.

But in the words of chief health officer Ashley Bloomfield, it is “just a moment in time.” The real deal is the general trend, not only in the numbers of cases, but also in the types of cases and how they have changed over time.

If there were 10 new cases, for example, but they were all safely quarantined at the border, then the threat of an outbreak is minimal or nil.

As blog authors Gordon Purdie, Nick Wilson, and Michael Baker say, the data presented may well shed light on possible community transmission, as well as any gaps in our phase-out plan.

Any international aircrew with the virus or any case related to an infected arrival abroad would show a weakness in border measures.

Data on Kiwis that captured Covid-19 from someone not linked to an imported case would shed light on the ability to trace contacts.

A nurse with a positive result would reveal a failure to contain the infection in hospitals, while a positive test from an asymptomatic group could be a sign of a previously undetected chain of transmission.

The change in these numbers over time would show if our border measures were working, if our contact tracking improved, as Bloomfield has stated, and if we needed more protection for hospital staff.

The most critical category is cases where the source of infection is unknown. As Ardern and Bloomfield have repeatedly told us, these are the most dangerous because there may be branches of transmission that are more difficult to identify, trace, and isolate.

Under more flexible alert level constraints, one undetected case could quickly turn into dozens of cases.

There were only two cases with an unknown source of infection when the Prime Minister made the call to bring us all to a national closure.

It would be much more helpful for the ministry to give us a daily update on these specific cases and the trend for the last day, week and 28 days (two 14 day incubation cycles).

Trying to find this information has been, to put it mildly, challenging.

In an exchange I had with the Ministry of Health three weeks ago, they told me that there were 30 of those cases and that they were classified as “community transmission.” But according to the ministry’s website, there were supposed to be 42 cases of community transmission at the time.

Asking how 30 aligned with 42 led to an answer that they were not, in fact, community broadcast, but were classified as “source under investigation.” But there were also supposed to be 42 such cases at the time, raising the same question.

Ultimately, the ministry seemed to realize that their classifications were not very helpful, and they were changed to include a category of locally acquired cases with an unknown source of infection, but no timeline.

They currently account for 4 percent of all cases, or about 60 cases in total, but many of them are no longer active due to the blockade’s success.

It seems the only way to find out the number of recent cases is to ask Bloomfield directly at his press conferences, and he has always provided answers, suggesting the data is there, but a decision has been made not to post it on the website of the ministry.

This also means, incredulously, that public health experts who want this information have to watch press conferences in hopes that the question will be asked and Bloomfield will have an answer.

Some of these experts are even advising Bloomfield on the Covid-19 threat in New Zealand.

Even when Bloomfield provides answers, it can be confusing. He has revealed that some cases have appeared in Timaru, Whanganui, and Te Puke.

Yesterday, he said there were two unsolved cases: one at Nelson-Marlborough and one from the workforce at Auckland airport. But there is no explanation of what happened to the Te Puke, Whanganui or Timaru cases. Does that mean they have been resolved? If so, how?

The ministry’s data problems are not new.

In late March, it fell back quickly after it stopped giving daily updates to test numbers when those numbers fell.

Last month, when the number of tests reached a respectable level, Baker lamented the lack of a regional or demographic context, and the ministry began publishing test data in every DHB and in every ethnic group.

But this has not been updated since April 18.

Baker previously regretted poor contact tracking data, which was later uncovered in an independent audit that revealed the lack of an end-to-end system that could tell us when a case was first tried, if the outcome of the proof. and how long it took to trace and isolate the contacts.

Bloomfield says the Ministry aspires to have this end-to-end system, but it is not yet clear if we are there.

Ideally, all this information should be before the Cabinet when it makes its big decision on Monday.

But it should also be available to public health experts and members of the public on a regular basis.

That would go some way to maintaining a high level of public confidence, which is crucial in bringing the public along with any decisions Ardern and his cabinet make.