COVID-19 Pandemic

The charts of Our World in Data

This slidedeck is updated daily at noon London time.

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Our main page on the pandemic is: OurWorldInData.org/Coronavirus

This chart shows the number of confirmed deaths due to COVID-19.

How you can interact with this chart:
By default you see the death counts for 10 different countries. But this chart is interactive: by clicking on + Add Country you can compare the data for any countries in the world you are interested in.

You find the same option on many of our charts.

How to share this chart:
If you click on the title of the chart the chart will open in a new tab. Then copy-paste the URL and share it.
(The selection of countries you choose is stored in the URL, so you can share the view of the chart you created.)

This is possible with all our charts.

How rapidly did the number of confirmed deaths increase in different countries? – This chart can give you the answer.

Each country's trajectory begins on the day when that country had more than 5 confirmed deaths. This allows you to make comparisons between countries.

Three tips on how to interact with this chart:
• Clicking on any country in the chart highlights that country. If you click on several countries you can create a view in which you can compare several countries.

• Any country you might not see immediately you can find via the ’Select Countries’ in the bottom left. Just type the name in the search box there.

• To focus on the countries you highlighted click on 'Zoom to selection'.

The previous chart looked at the increase of total deaths – this chart shows the number of confirmed deaths per day.

• In countries that responded well to the pandemic the death count stayed low – South Korea is an example.

• In other countries – for example Italy, Spain, and the US – the number of confirmed deaths increased very rapidly for several weeks before the growth rate declined.

How you can interact with this chart: The default log view is helpful to compare the growth rates between countries: on a logarithmic scale the steepness of the line corresponds to the growth rate.

But in this chart, as in many of our charts, you can switch to a linear axis. Just click on ‘LOG’.

Here is an explanation for how to read logarithmic axes.

This chart shows the same data as before, but now adjusted for the size of the population – it shows daily confirmed deaths per million people.

It makes sense to adjust for the size of the population because the death count in more populous countries tends to be higher. [Here you can see this correlation.]

Related chart: The chart showing total confirmed deaths per million can be found here.

This chart shows the daily confirmed deaths due to COVID-19, given as the rolling average over three days.

Why a three-day rolling average?
For all global datasources on the pandemic, daily data does not necessarily refer to deaths on that day – but to the deaths reported on that day. Since reporting can vary very significantly from day to day this chart shows the three-day rolling average of the daily figures.

A tip on how to interact with this chart:
By pulling the ends of the blue time slider you can focus the chart on a particular period.

If you bring them together to one point in time then the line chart becomes a bar chart.

The previous chart looked at daily deaths per million people. This map shows total confirmed deaths per million people.

Two tips on how to interact with Our World in Data maps:

• You can drag the blue time-slider below the map to any other position – the map changes to the date you are interested in.

• In all our maps you can click on any country to switch to the chart view and see its change over time.

You can embed any of our charts in your work.

We wrote this detailed explanation for how to embed any chart or map
– it is as simple as embedding a Youtube video.

Many journalists regularly embed COVID-19 charts from Our World in Data in their work.
• Here is an example from the Washington Post, here one from The Guardian, and here is one from Vox.
• There are many more examples every day.
All of our work is free, open-source and provided as a public good:
• Our goal is to make sure that good data is readily available for everyone in the world.
• We do our work so that others can build on it, use it and benefit from it.

Confirmed cases and testing for COVID-19

This chart allows you to compare the trajectory of confirmed cases between countries.

• Spain and the US had particularly rapid outbreaks. Within two and a half weeks the number of confirmed cases reached 10,000 and continued to rapidly increase after that (as you can see, the US had 100,000 confirmed cases within 25 days after having the 100th case).

• In South Korea the speed of the outbreak was much slower, after 6 weeks there were 10,000 confirmed cases and the growth rate stayed slow even then.

What are the grey lines in the background? These lines show the trajectories for doubling times of 1, 2, 3, 5, and 10 days.

If the slope that a country is on is steeper than a particular grey line, then the doubling time of confirmed cases in that country is faster than that.

For example, there are several countries for which the slope was steeper than the ‘…every 2 days’ line – this means their case count doubled faster than every two days.

The Our World in Data COVID-19 Testing dataset – why is it important?

• Confirmed cases are those with a ‘lab confirmed infection’.
This means that the counts of confirmed cases depend on how much a country actually tests.

• To interpret any data on confirmed cases we need to know how much testing for COVID-19 the country actually does.

• That is why we – the at Our World in Data team – have focused our efforts on building a global dataset on COVID-19 testing.

We are constantly expanding and updating this database,
you always find our latest version here: OurWorldInData.org/covid-testing

And as with all our work, it is freely accessible for everyone (the data is here on GitHub).

This chart shows the number of daily tests per thousand people.

There are extremely large differences between countries as this chart shows.

Some countries do very few tests.

What is counted as a test? The number of tests does not refer to the same in each country – one difference is that some countries report the number of people tested, while others report the number of tests (which can be higher if the same person is tested more than once). And other countries report their testing data in a way that leaves it unclear what the test count refers to exactly.

We indicate the differences in the chart and explain them in detail in our accompanying source description.

This shows the total number of tests in each country.

To allow comparisons between countries it is again shown relative to the size of the population.

In all our charts you can download the data: We want everyone to built on top of our work and therefore we always make all our data always available for download.

Click on the 'Data'-tab below the chart and you can download the shown data for all countries in a simple to use csv file.

This chart brings our data on testing together with the data on confirmed cases.

The chart answers the question: How many tests did a country do to find one COVID-19 case?

• Some countries – for example Taiwan and Vietnam – did a large number of tests per each confirmed case.

• For others the ratio is more than two orders of magnitude lower. These countries found a case for every few tests they did.

This shows the correlation between tests per capita and GDP per capita.

There are a few exceptions, but poorer countries tend to do fewer tests for COVID-19.

This suggests that particularly in poorer countries the number of total cases is likely much higher than the number of confirmed cases.

We looked at this chart before we started looking at the testing data.

Now that we’ve seen the large cross-country differences in testing it is clear why it is crucial to interpret any data on confirmed cases in the light how much testing a country actually does: Without testing there is no data.

And in countries that do very little testing the total number of cases can be much higher than the number of confirmed cases.

The previous charts allowed you to compare countries.

This is a chart that is helpful to understand the spread of the disease in a single country – in this case South Korea.

In yellow you see the number of daily new confirmed cases and in red the total sum of confirmed cases.

In late February the country experienced a very rapid outbreak – South Korea was on a trajectory that was just as steep as the one of Italy.

But by early March it turned things around, bringing the number of confirmed cases down to around 100 per day.

This is the same chart, but showing the data for Spain.

For much of March the daily number of confirmed cases increased day by day – the total number of cases was growing exponentially.

How to interact with this chart: On these charts you see the button Change Country in the bottom left corner – with this option you can switch the chart to any other country in the world.

Have a look at Switzerland for example.

The number of confirmed cases in Switzerland grew exponentially for almost one month, but then the country was able to stop this exponential growth and the daily number of cases stopped increasing.
(A constant number of daily cases means that exponential growth is over and that the total case count is growing linearly.)

The previous chart helps us understand a single country. This chart allows the comparison across countries.

It shows the daily number of confirmed COVID-19 cases.

Five quick reminders:
• By clicking on + Add Country you can show and compare the data for any country in the world you are interested in.

• If you click on the title of the chart, the chart will open in a new tab. You can then copy-paste the URL and share it.

• You can switch the chart to a linear axis, by clicking on 'LOG'.

• If you move both ends of the time-slider to a single point you will see a bar chart for this point in time.

• You can switch to the 'Map' tab.

To bring the pandemic to an end, every country has to bring the curve of daily cases down to zero.

This chart allows you to track whether countries are achieving this or not.

This is the same chart, but showing daily confirmed cases relative to the size of each country’s population.

So far we focused first on confirmed deaths and then on confirmed cases.

This chart shows both metrics.

How to interact with this chart: By now you know that in these charts it is always possible to switch to any other country in the world by choosing Change Country in the bottom left corner.

This chart shows the total number of confirmed cases on the horizontal axis against the total number of confirmed deaths on the vertical axis.

The ratio between these two measures is what epidemiologists call the case fatality rate (CFR).

The grey lines show the CFR. For instance, if a country lies along the 2% line, its current confirmed cases and death figures indicate it has a case fatality rate of 2%.

During an outbreak – and especially when the total number of cases is not known – one has to be very careful in interpreting the CFR. We wrote a detailed explainer on what can and can not be said based on current CFR figures.

The previous slide makes it very transparent how the case fatality rate is calculated – it is simply the ratio between the confirmed deaths and the confirmed cases.

This chart here plots the CFR calculated in just that way.
Again, because it's important:
During an outbreak – and especially when the total number of cases is not known – one has to be very careful in interpreting the CFR. We wrote a detailed explainer on what can and can not be said based on current CFR figures.

Earlier in this pandemic we partnered with our friends from the Youtube channel Kurzgesagt to produce a video on the pandemic.

Many viewers told us that this video helped them to take the pandemic much more serious and that it convinced them to do what they can to reduce the spread of the virus.

We hope you like the video!

⭠ This is our homepage.

The mission of OurWorldInData.org is to give everyone access to the data on the big global problems and the research that helps to make progress against them.

If you think that research & data are needed in the fight against the pandemic then you understand our motivation.

We hope these slides are helpful to understand the pandemic that we are all fighting.

You can follow us at @OurWorldInData or like us (here) on Facebook.