Covid 19 interactive: How do we compare?

Chris Knox
Chris Knox

Data Editor and Head of Data Journalism, NZ Herald

All of the New Zealand Herald's Covid-19 interactive graphics in one place.

We are keeping the charts below up to date with the latest Covid-19 numbers from New Zealand and around the world. Come back here whenever you need a quick status update, or when you want to explore the details.

New Zealand numbers will be updated each day shortly after the Ministry of Health's 1pm press briefing.

How does New Zealand compare with Australia and the rest of the world?

The next four graphs show New Zealand and Australia. You can add other countries to the plots. Or remove them.

Comparisons between countries are never perfect. Both the amount of testing and case definitions vary between - and in some cases within - countries.

Infections in both New Zealand and Australia appear to have peaked at about 0.02 per cent of the population. In the United States more than 0.2 per cent of the population is infected and the increase does not appear to be slowing.

By April 22, almost 2 per cent of New Zealand's population had been tested for Covid-19.

While New Zealand's case numbers have levelled off, the United States is heading towards one million cases.

The percentage of confirmed Covid-19 cases that result in death varies a lot between countries. In New Zealand just under 1 per cent of cases have resulted in death, in Italy and Britain more than 14 per cent of confirmed cases are fatal.

Modelling by researchers from Te Pūnaha Matatini has estimated the average number of people infected by someone with Covid-19 and how it has changed with different Government interventions - go here to read more.

The majority of New Zealand's Covid-19 cases have now recovered.

New Zealand Covid-19 Cases over time

The first graph is a running tally of the overall number of Covid-19 cases in New Zealand.

Our second graph shows how many cases were reported each day. We can see after the alert level 4 restrictions were enacted, the daily number of new cases has flattened off.

Looking only at the total number of cases in New Zealand without considering their origin can be misleading. Initially, most of our cases were imported from overseas. Now, the number of cases originating in New Zealand is the same.

The decrease in imported cases can be seen in this daily tally of cases originating overseas.

Equally, the increase in local cases can be see in this daily tally of cases originating in New Zealand.

A decrease in the percentage of tests that are positive is one sign that the actual number of infections is decreasing.

New Zealand and the rest of the world

The chart below compares the growth in New Zealand Covid-19 cases with the rest of world. Each country's case totals have been aligned so the first day on the graph is the first day that country reported 50 or more cases.

The graph uses a logarithmic scale, meaning the first 1000 cases take the same amount of space on the graph as cases 1000 to 10,000 and 10,000 to 100,000. This type of graph is useful for comparing the rate of spread of a virus, but it can also be misleading. For example, New Zealand's is about half the distance up the graph as Austria - but Austria has more than 10 times the number of cases - so take care reading this graph.

Covid-19 cases around New Zealand

Here is a quick overview of where in New Zealand Covid-19 cases are.

Covid-19 around the world

In this article we have collected up all the Covid-19 charts we have made, including the ones we are no longer using.

The world map is no longer being used because it has basically become unreadable. However you can click on the bars at the bottom of the graph to see how many cases had been reported around the world on any given day going back to January 22.

The "Flatten the curve" interactive below is also no longer being used. This is largely because it was realised that just flattening the curve is insufficient to prevent medical systems from being overloaded.

Case number comparisons between countries should always taken with a grain of salt. Countries have different case definitions and testing protocols. The value in the chart above is in comparing the slope of each country's curves, not necessarily the absolute heights.

Data sources

• All international data is provided by Johns Hopkins and is refreshed several times a day.

• New Zealand data is provided by the Ministry of Health and updated at 1pm each day. The New Zealand Herald has also made this data available here. The Government's official Covid-19 advisory website

• The 'Wee People' font was provided by ProPublica under a creative commons license.