Director of health Ashley Bloomfield, who reads the numbers that will define how the rest of this year plays out (Illustration: Simon Chesterman)

Covid-19: New Zealand cases mapped and charted, April 30

The latest in our series of charts, graphics and data visualisations by Chris McDowall. David Garcia worked with Chris to create today’s charts.

This work is entirely funded by the generosity of The Spinoff Members, with support from the Science Media Centre

These posts collate the most recent statistics and present them as charts and maps. The Ministry of Health typically publishes data updates in the early afternoon, which describe the situation at 9am on the day of release. These data visualisations are interactive so use your mouse or thumb to hover over each graph for more detail.

This afternoon’s Ministry of Health figures report that the total number of confirmed and probable Covid-19 cases increased by two to 1,474 (1,129 confirmed and 347 probable). This is the 12th consecutive day of single-digit increases. A total of 1,241 people have recovered which is an increase of 12 since yesterday. There were no further deaths overnight.

The number of significant clusters with 10 or more cases remains at 16. There are seven people in hospital which is an increase of one since yesterday. For the second day running, there are no known Covid-19 cases in intensive care units.

Yesterday, 5,867 tests were processed. The ministry reported averaging 4,756 Covid-19 lab tests per day during the week ending April 28. A total of 134,570 lab tests have been conducted since January 22. There are 67,542 test supplies in stock, up from 64,442 yesterday.

This chart compares active and recovered cases. Active cases are confirmed or probable cases of Covid-19 where the person has neither recovered nor died. Recovered cases are people who were once an active case, but are at least 10 days since onset and have not exhibited any symptoms for 48 hours.

The overall downward trend of active case counts that started around April 8 continues. Note how the blue curve is levelling off, while the purple bars continue to decline. This means there are very few new cases being reported while existing cases steadily recover.

Previously this chart began on March 1. For better legibility, we updated it so that the first date is Sunday, March 19. On this day there were 28 active cases and no reports of recovery. The change makes it easier to interact with the chart’s bars, while still showing the main growth period.

A few readers have asked for summaries of district health board statistics by case status. This table shows the number of active cases, recovered people and deaths in each area. Whanganui, Wairarapa, Tairāwhiti and West Coast all have no active cases. The largest number of active cases are in Waikato (37), Canterbury (36), Waitamatā (35) and Auckland (22).

You can sort the table’s rows by clicking on the columns titles.

The symbol map shows confirmed and probable Covid-19 cases arranged by district health board. In keeping with the relatively small number of new cases, there is minimal change in regional counts. Waitematā (no change at 223), Southern (no change at 216), Waikato (down one to 186) and Auckland (up one to 173) remain the four district health boards with the largest number of active cases.

The drop in Waikato was due to a case previously classified as probable getting reclassified as not a case. There were increases in Auckland (up one to 173), Counties Manukau (up one to 127) and Nelson Marlborough (up one to 49). This sums to a net increase of two new cases overnight.

There are 16 significant clusters under investigation by the Ministry of Health. Once again, no new cases were reported in any of these clusters overnight.

This chart shows the number of active, recovered and deaths associated with each cluster. The ministry has not released formal counts associating deceased persons with clusters. Instead, we compiled these numbers from ministry media releases about each case.

In most clusters, the number of recovered cases outweighs the number of active cases. Three clusters buck this trend. Both Auckland residential care facilities and the Rosewood aged care cluster in Christchurch all have more active than recovered cases.

This chart shows cases by the date they were first entered into EpiSurv, ESR’s public health surveillance system. Note that the number of cases reported on a particular date may not match the number of cases reported in the last 24 hours. This is because the number of confirmed and probable cases reported in the last 24 hours includes cases that were entered on an earlier date as “under investigation” or “suspected” whose status has now been changed to confirmed or probable.

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