Amazing rates

The IHU Mediterranee Infection, the Marseille hospital that claims that hydroxychloroquine + azithromycin treatment will cure almost everyone infected with COVID-19 has been reporting very low death rates for COVID-19 patients. As of today, their website reports that the IHU has a much lower death – 1.7% – than the worldwide COVID-19 mortality rate of 6.2%.

While that might look amazing at first glance, these numbers are not surprising, given the high numbers of virus tests that the institute has been performing. Let’s take a closer look at their testing to better understand how the Marseille hospital can get such low mortality rate numbers.

I calculated the death rate (“mortality rate”) simply by the number of COVID-19 deaths divided by the number of confirmed cases. Please let me know in the comments below if this is an incorrect calculation or definition, and I will be happy to correct. This is just a simple calculation that appears to make sense for this post.

As per today (April 14, 2020), the IHU reports a worldwide mortality rate of 6.2% (119,654 deaths amongst 1,922,446 confirmed cases) while the death rate at the IHU institute itself is only 1.7% (74 deaths and 4,292 cases).

As often in calculations, it is all about what the denominator is.

Prof. Didier Raoult himself, the director of the Marseille institute, stated that the city of Marseille might be one of the highest-tested population in the world.

And doing a lot of testing will make the death rate of a region appear to go down. Let me explain below in more detail.

Different countries, different death rates

The numbers as reported on the WorldOMeter site show that the mortality rates are very different between individual countries. Here are some numbers of today (April 14, 2020) to illustrate, focusing on North American and European countries:

• USA – 613,886 cases – 26,047 deaths – 4.2% mortality
• Spain – 174,060 cases – 18,255 deaths – 13.4% mortality
• Italy – 162,488 cases – 21,067 deaths – 13.0% mortality
• France – 143,303 cases – 15,729 deaths – 11.0% mortality
• Germany – 132,210 cases – 3,495 deaths – 2.6% mortality
• UK – 93,873 cases – 12,107 deaths – 12.9% mortality
• Belgium – 31,119 cases – 4,157 deaths – 13.4% mortality
• Netherlands – 27,419 cases – 2,945 deaths – 10.7% mortality
• Canada – 27,063 cases – 903 deaths – 3.3% mortality

Why are the percentage of deaths amongst people with confirmed COVID-19 infections so different between countries? There are many reasons that could explain that. Countries differ in health-care accessibility, number of ICU beds and ventilators per 1,000 people, obesity rates, average age of the population, etc. But they also differ in the amount of SARS tests available.

Germany has a low death rate because they tested many more people

If you look at the numbers above, you see that Germany has a much lower mortality rate than other European countries, <3%, while surrounding countries such as the Netherlands, Italy, Belgium, and France all have double digit numbers. Several articles have been written about why that is the case (here, here, and here), concluding that the large numbers of tests available in Germany might be one of the main reasons why the COVID-19 death rate in that country is so low.

In most countries, SARS-CoV-2 PCR tests were only performed on very sick people. People who were only mildly sick were told to stay at home and only go to the hospital or to see a doctor if they were severely sick. So many people might have had a mild case of COVID-19, but have not been tested. However, in Germany testing was much more widely available, including for younger and only mildly-sick patients.

Obviously, mortality rates will be much higher among people who are very sick. So, a country that only tests very sick people during a viral pandemic will have a higher percentage of people with a positive test who will die of the disease. In contrast, a country that also allows mildly sick people to take the test will find lower mortality rates.

Marseille is the largest tested population in the world

Let’s go back to the IHU Mediterranee Infection hospital in Marseille, and their amazingly low mortality rates. One of the main reason their death numbers are so low might be because they offered the SARS-CoV-2 test to anyone who walked up to the hospital with a fever.

You might remember the long lines of hundreds of people who were all waiting to be tested. They were standing in line for hours, so it is safe to assume that most of these people were not very ill, but only had some mild symptoms.

And let’s repeat here that the institute’s director, Didier Raoult, himself said that Marseille’s population was the highest-tested population in the world (source: http://world-today-news.com/the-world-champion-city-for-covid-19-screenings/)

It seems very likely that by testing large amounts of people, including thousands of young and only mildly-ill people, the IHU Mediterranee Infection hospital in Marseille appears to have a much lower death rate than that in the rest of the world.

It is all about the denominator.