Growth Rates

Here I a looked at the growth rates for several countries. After downloading the data, I plotted the number infected on a log plot after the 100th infection.

This graph is a bit complex at initial glance, but it can be easily distilled. The horizontal axis is the days since the 100th case. The vertical axis is a log scale ranging from 100 to 80,000. Also notice there are diagonal white dashed lines. These  lines are the growth rates for the number infected in a country to double. So if a country is tracking between the 2 and 3 days lines it means it takes between 2-3 days for the number infected to double.

Notice how China and South Korea have curves which are horizontal. The data only goes to the 25th day post their 100th infection, the most current data points are not plotted as they are off the graph.

If we remove some countries we can see a few countries of my personal interest.

Of note here is that the USA is crossing the Italy curve, which means the USA is now increasing its numbers of infections compared to Italy when it was at this point. Right now Canada appears to double every 2-3 days where as Australia is 3-4 days.

Two Week Forecast (March 20 - April 4)

Here I downloaded data from here. And made predictions for the next two weeks. Data was modelled in MATLAB via a fourth order polynomial.

Here we can see that Canada will overtake Australia and has about 12000 cases predicted in 2 weeks from now. Australia will have about 7700. The United States will pass 110,000 cases and globally expect upwards of 900,000 by the fourth of April. Beyond these two weeks is when policy changes such as social distancing can be seen and the slope of these lines will start to decrease. 

Short Term Predictions

It appears that the COVID-19 pandemic is unrelenting at the time of this writing. Today there are 170,000 infections globally. If I plot the data from the 17th of February until present day, the data fits a polynomial function of fourth order. I have not used data before this as around the 17th of February is when the number of cases around the world started to increase and cases in China started to plateau.

Over the next two weeks the total number of global cases is expected to exceed 700,000.  If I take the derivative of the curve and I can see the total number of new infections per day.

Currently there are about 10,000 new infections per day, however in just two weeks time there will be nearly 70,000 new infections per day.

I'll come back in two weeks to revisit this predictions.

COVID-19 Analysis

With the ongoing SARS-CoV-2 virus on its current global pandemic of causing COVID-19 there is a lot of interesting data to be analysed. Getting a hold of the data isn't very easy, but I managed to get it from the worldometers website and using Wayback Machine I was able to get data for a few countries of interest. I have made some interesting plots below and it provides some details on the expected trajectory of the pandemic. 

This is a basic plot of selected countries and the total number of infections tracing back from today. Of interest here is that China and South Korea have very similar curves whereas the rest of the countries have clear exponential curves. I didn't fit the data in this post perhaps I will later when there is more data available for these countries of interest. Notice the "S" shaped curve for both the China and South Korea curves. This is a logistic curve, and we can see that the total number of infections has reached a plateau. China can do this because with its authoritarian government it can hold people against their will and force them into isolation.  South Korea seems to have made progress via mass scale testing alone unlike any other developed country. The other countries are either unable to have Chinese style control or are several weeks to months away from mass scale testing like South Korea.

Now take the derivative of the first set of data. This would represent the number of new infections per day. Notice how China and South Korea are both downtrending which is due to their control of the virus. Norway appears to be downtrending however there is due to just a couple of data points and it can go up. 

What if we take another derivative. Now this is the rate of change of the number of new infections. A negative value here implies the Ro value is below 1 and the virus spread is starting to become contained. This is also known as the inflection point which was covered in introductory calculus courses. Once the second derivative is below zero the virus will start to become contained. China and South Korea both have second derivatives below zero. It does not look promising for everyone else.

The last set of data I'll explore here is the number of infections per million. Here it looks like the United States is the best off country and they appear to be doing very well. The United States, Australia and Canada are all several weeks behind the other infected countries. I would expect Canada and Australia to have very similar numbers over the next few weeks owing to similar healthcare systems. Of all the countries mentioned here so far the USA is the biggest wild card. There has been more testing at the hospital where I work over the last month than there has been in the entire United States and the numbers for the United States are highly underreported.  Also the United States is the only country which is does not have universal healthcare and this could result in many people not be treated, which is something I have not heard about in any media post thus far.

Here there is a zoom out of the previous plot. Italy, Iran and Norway are some of the hardest hit countries. South Korea still has more cases per million, however the trajectory of Iran and Norway will surpass South Korea very soon.


I'll revisit this data over the next month or so and hopefully the world won't split into chaos and anarchy.

Now go wash your hands...