Pandemics and data: it depends on the vantage point

As of March 27, 2020, the confirmed cases of COVID-19 in the world exceed 592 thousand and more than 27 thousand deaths are registered. The case-fatality rate (deaths among confirmed cases) increases and in 15 countries it is higher than the maximum rate observed in China. Given the impact that social distancing measures already have on the activity of companies and businesses, in a couple of weeks the world economic situation went overboard and the prospects are now, in addition to greater numbers of victims of the pandemic, a serious recession and significant loss of jobs.

CFR_27-mar-20pngOwn elaboration with data from the John Hopkins University dashboard

Despite the above, it has been difficult to convince some sectors of the public and some authorities of the seriousness of the emergency. The reduction in travelers is due to the closure of borders and imposed restrictions, rather than to the conviction of people that travel should be avoided. Voices in various parts of the world still call for relaxation or graduation of social distancing measures, to mitigate the economic damage. Social networks report cases that had their origin in an underestimation of the risk by the affected people.

Some of this may have to do with how the pandemic data is reported. In the media we hear absolute figures and comparisons that omit the size of the countries and the fact that the disease started at different times in each one. Almost always the reference is confirmed cases and deaths in China and against them the progress of the crisis is measured in Italy, Spain and, now, the United States. Thus, the news is that the confirmed cases in Italy and the United States exceeded that of China and that the deaths in Italy and Spain are higher than those in that country.

In places like Mexico, where we are about to reach 1,000 confirmed cases, the figures of 86,000 or 65,000 cases are far away and it is easy to think that the situation here is different. Therefore, another vantage point is necessary. If we use the confirmed cases per million inhabitants as a measure, to consider the size of the country, and follow the behavior from the day that there was more than 1 case per million, so that all countries start at the same time, a different situation appears. Obviously, within countries territory the situation does not evolve the same everywhere, but this metric allows us to appreciate the differences from one nation to another.

The leftmost graph below shows the behavior of confirmed cases in China, South Korea, the United States, Spain and Italy, the data we hear every day. China appears as the country with the highest incidence, with the United States and Italy catching up to it in recent days. On the right, the behavior of the cases per million inhabitants in the days that have elapsed since there was more than 1 case per million is shown. The picture is completely different.

mesaurementspngOwn elaboration with data from the John Hopkins University dashboard

The situation in Spain and Italy is extremely more serious than in China. The more than 86 thousand cases in Italy are equivalent to 1,422 cases per million inhabitants (one in 700 Italians has contracted the disease), while the 81 thousand cases in China are equivalent to only 58 cases per million. In Spain, unfortunately, the incidence grows even faster than in Italy, and in the United States it is worrying that, 20 days after there was more than 1 case per million, the incidence exceeds that of Italy at 20 days. In none of the 3 cases was a slowdown observed.

With this same criterion, what is the situation in all countries in general? According to the data sets available on the John Hopkins University dashboard, as of March 27, there are 97 countries and territories reporting more than 100 confirmed cases. The graph below shows the evolution of cases per million inhabitants, again in the days that have elapsed since there was more than 1 case per million, for those 97 nations.

cases_per_million_27-mar-20pngOwn elaboration with data from the John Hopkins University dashboard

The spread of the pandemic is greatest outside the place where it originated. In most countries, the number of cases per million greatly exceeds that observed in China or South Korea. Italy and Spain are very serious cases, but the incidence is even higher and growing faster in Switzerland, as well as 5 small countries (San Marino, Faroe Islands, Andorra, Luxembourg and Iceland).

If we look carefully, it seems that the growth of cases per million in the first 25 days is related to subsequent behavior. Those who exceeded 500 cases per million before 25 days have accelerated their growth, while those who reached 25 days with less than 250 cases per million have not grown as much. The graph below shows the detail.

cases_per_million_25d_27-mar-20pngOwn elaboration with data from the John Hopkins University dashboard

At this scale we can identify the three groups, 12 countries that suffered an acceleration of the disease after exceeding 500 cases per million within 25 days, 17 that did not exceed 250 cases per million before 25 days, which have not had a significant acceleration, and 68 that until March 27 it is not seen how they will evolve. The countries that make up the 3 groups are.


Own elaboration with data from the John Hopkins University dashboard

In this context, what is the situation in Mexico? How does the disease behavior so far look compared to that of other nations? The graph below shows a close-up of the graph to cover only the first 10 days after 1 case per million was exceeded, for a representative sample of countries and Mexico.

cases_per_million_10d_27-mar-20pngOwn elaboration with data from the John Hopkins University dashboard

Until March 26, 2020, Mexico has a relatively low spread of the disease, although the report is on the 7th day that 1 case per million was exceeded, so the situation may change at any time. According to what we have seen, the next 18 days (until April 14) will be very important and can determine the future behavior of the coronavirus in our country.

When we consider the size of a nation, as well as the number of days that have passed since 1 case per million inhabitants was overcome, we better appreciate the dynamics with which COVID-19 is spreading around the world. There are 12 countries that show a high spread and there are another 68 in which we do not know how the situation will evolve. Faced with this uncertainty, the only way to contain the disease is with hygiene and social distancing measures, so they must be followed to the letter. These are very high cost measures but adopting and abiding by them will save many lives and help reduce the time they need to be applied.

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