Some Perspective on the Covid Pandemic

What happened in July?

Published: Tuesday, July 28, 2020 - 12:03

With data that come along one number at a time, it is easy to get lost in the details. To see the big picture, it helps to use a time-series graph that will draw your eye in the direction that your mind wants to go. These simple graphs reveal how the values are changing over time and thereby place each value in context, making them more easily understood. Here we will look at some time-series that provide a global perspective on the Covid-19 pandemic.

Comparable numbers

With 329 million people, the United States is the third largest country in the world. China and India have more than four times the population of the United States, and fourth-place Indonesia has only 82 percent of the population of the United States. These size differences make direct comparisons misleading, which is why data are often normalized and expressed as rates per million population. While these rates provide an equitable basis for making comparisons, the per-capita rates are one step removed from the original values. A conversion is required to turn these rates into values we can expect to see in practice. This conversion is not complicated, but it nevertheless creates an obstacle for readers to either hurdle or stumble over.

Therefore, in the interest of clarity, the following summary will be based on the original values rather than per-capita rates. To create a rational basis for making comparisons using the original values, I have created groups of countries where each group has a combined population that is similar to that of the United States. This allows for reasonable comparisons using the original data.

The data

Here we shall use the daily numbers of confirmed cases of Covid-19, as reported by the European CDC, for each of the countries involved. These values are lower bounds for the actual number of cases of Covid-19 in these countries. However, these values, along with the number of deaths from Covid-19 each day, are the only values I have found that are available on a daily basis going back to the beginning of 2020 for all the countries around the world. For each group of countries defined below, these daily numbers of new cases will be combined into group totals.

Since some countries report these numbers only five days a week, I used a seven-day moving average to smooth out the weekly cycles and the day-to-day noise. These seven-day moving averages show the underlying trends for each country or group of countries. These averages will be plotted against the midpoint of the period represented. That is, the average for July 16 through July 22 will be plotted as the value for July 19.

The countries

The Western European group consists of Spain, Italy, France, Germany, and the United Kingdom. These five countries have a combined population of 324 million, which is 98 percent of the population of the United States.

The Pacific group consists of South Korea, Japan, the Philippines, and Australia. These four countries have a combined population of 311 million, which is 94 percent of the population of the United States. The time-series for the average daily number of new cases for these two groups are shown in figure 1.

Western Europe had a quickly rising number of cases in March 2020 that peaked at an average of 25,538 new cases per day on April 3, 2020. Since that peak the Western European averages have steadily declined to the present average of 1,860 new cases per day. However, the Pacific group never let the pandemic get out of hand. Presently about two-thirds of the new cases are coming from the Philippines, while the other three countries are maintaining very low growth rates.

Figure 1: Average daily new confirmed cases of Covid-19 for Pacific and Western European groups

India has 1,366 million people, which is 415 percent of the population of the United States. Here we will have to use a rate in order to obtain values to compare with those from the other groups. One-fourth of 1,366 million is 342 million, which is within the range of populations being considered. Therefore, the seven-day averages for India will be divided by four and the results plotted in figure 2.

The African group consists of Egypt, Nigeria, and South Africa. These three countries have a combined population of 360 million, which is 109 percent of the population of the United States.

India has shown a slow but steady spread of Covid-19. Its current average daily number of new cases is 32,522. When this value is divided by four, we get a comparison value of 8,143 new cases per day per 342 million people. The African countries had a slow start in March, but they have shown a steady climb since then to the current average of 13,263 new cases per day.

Figure 2: Average daily new confirmed cases of Covid-19 for India and the African group

The South American group consists of Brazil, Columbia, Argentina, and Peru. These four countries have a combined population of 339 million, which is 103 percent of the population of the United States. The seven-day averages of new confirmed cases of Covid-19 for both the United States and the South American group are shown in figure 3.

Figure 3: Average daily new confirmed cases of Covid-19 for South America and the United States

The South American countries started more slowly than Europe and the United States, but their average number of new cases per day started to climb more rapidly after April 20, 2020. Between the last week of May and the last week of June, they even outstripped the United States in the average number of new cases per day. This group’s current average number of new cases per day is 49,103.

The United States went from an average of 123 new cases per day on March 8, 2020, to 31,942 new cases per day on April 8, 2020. After spending four weeks averaging about 29,000 cases per day, the United States dropped down to a plateau of about 22,000 cases per day for the next six weeks. Then, as the United States started to “open up,” we see a new wave of infection beginning in the middle of June that has taken the United States up to the current average of 67,212 new cases per day.

Summary

As of July 22, 2020, the world was averaging 227,336 new cases per day, which is about 1.6 million new cases per week. The five Western European countries, with 4.3 percent of the world’s population, are contributing 0.8 percent of these new cases.

The four Pacific countries, with 4.1 percent of the world’s population, are contributing 1.2 percent of these new cases.

India, with 17.9 percent of the World’s population, is contributing 14.3 percent of these new cases.

The three African countries, with 4.7 percent of the world’s population, are contributing 5.8 percent of these new cases.

The four South American countries, with 4.4 percent of the world’s population, are contributing 21.6 percent of these new cases.

And the United States, with 4.3 percent of the world’s population, is contributing 29.6 percent of these new cases. The U.S. infection rate of 67,212 new cases per day is 36 percent greater than the average infection rate in Brazil, Columbia, Argentina, and Peru (49,103 new cases per day). It is more than five times greater than the combined average infection rate average in Egypt, Nigeria, and South Africa (13,263 new cases per day).

Moreover, for every new case in India, there are two new cases in the United States (32,572 vs. 67,212). Since India has four times the population, this means that the Covid-19 infection rate in the United States is eight times greater than the Covid-19 infection rate in India.

Every day the odds are going up that the next person you come in contact with will be spreading Covid-19. So wash your hands frequently. Wear a mask that covers both your nose and mouth whenever you leave your house. And keep your distance from others. More than 600,000 people have died from Covid-19, and more than 140,000 of these have died in the United States. Don’t be one of tomorrow’s 67,000 new cases because you made bad choices today.

About The Author

Donald J. Wheeler

Dr. Wheeler is a fellow of both the American Statistical Association and the American Society for Quality who has taught more than 1,000 seminars in 17 countries on six continents. He welcomes your questions; you can contact him at djwheeler@spcpress.com.