During an interview that aired on Axios on HBO on Monday night, President Trump was interviewed by journalist Jonathan Swan. One of the topics: the number of deaths in the U.S. from COVID-19.
Swan noted that there are about 1,000 deaths a day in the United States.
Trump responded that the U.S. "is lowest in numerous categories" when it comes to the pandemic — including "case death." This measure, which epidemiologists call the "case fatality ratio," calculates the number of people with COVID-19 who eventually die from the disease.
Swan interjected, "I'm talking about death as a proportion of population. That's where the U.S. is really bad, much worse than South Korea, Germany, et cetera."
Trump replied: "You can't do that."
As Swan noted during the interview, you can in fact calculate the per capita death rate for a country's population — that is, the number of deaths per 100,000 people.
But it is difficult to compare death rates among countries. Neither per capita death rate nor case fatality ratio "fully reflect the effectiveness of a country's response," said Nilanjan Chatterjee, a professor of biostatistics at Johns Hopkins University.
However, these two ways of measuring the COVID-19 death toll can tell us something.
Since January, there have been over 4.7 million COVID-19 cases and 150,000 deaths in the United States.
Among the 45 countries with more than 50,000 COVID-19 cases, the U.S. has the eighth-highest number of deaths per 100,000 people: 47.93 deaths from the coronavirus for every 100,000 Americans. Belgium has the highest per capita death rate: 86.3 deaths per 100,000.
But in terms of case fatality ratio, the U.S. is doing significantly better than many other countries. The country's case fatality ratio is 3.3%, meaning that for every 100 people with COVID-19, only about three die.
Trump said that the low case fatality ratio in the U.S. was a result of his administration's effective pandemic response, such as closing international borders to people from COVID-19 hot spots such as China and the United Kingdom. He also stated that the U.S. has a high per capita death rate because the country has done more testing than any other in the world.
The per capita death rate is primarily an indication of the overall disease burden in a country, according to Justin Lessler, an associate professor of epidemiology at Johns Hopkins University. (Disease burden is the term used to describe the impact of a particular disease in terms of years of life lost and years lived with disability.)
If there is more COVID-19 transmission among communities in a specific country, then there will be more infections and consequently more deaths in that country — and presumably a higher per capita death rate.
But other factors influence the per capita death rate. For example, age is a major risk factor for severe COVID-19 disease and death. Therefore, countries with much younger populations may have far fewer deaths. In Uganda, for instance, the per capita death rate is 0.01, one of the lowest in the world. The median age of Ugandans is 15.9. By contrast, the median age in the U.S. is 38.4. In Belgium and the U.K., which have the highest number of deaths per 100,000 people, the median ages are 41.9 and 40.0 years, respectively. And predictably, the per capita death rate is higher in those countries.
Access to care also has an impact on the rate — whether patients have access to ventilators and ICU care if needed.
But even though the daily death toll in the U.S. has now averaged 1,000 or more a day for over a week, the per capita death rate is not necessarily the best metric by which to compare mortality among countries. According to Chatterjee, the case fatality ratio may be a slightly better indication of how well a country is doing in responding to the pandemic and preventing infected people from dying.
Among the 45 countries with over 50,000 cases, the U.S. has the 24th-highest case fatality ratio. And the U.S. rate of 3.3% is much lower than that of the U.K. at 15.1% or Italy at 14.2%.
So despite the daily death toll of 1,000 in the U.S., there is some truth to Trump's assertion that the low case fatality ratio is a positive sign in the United States.
As for his assertion that "we have tested more people than any other country," there is also some truth to this. The U.S. has conducted more coronavirus tests than any other country in terms of sheer numbers — more than 50 million.
However, when you consider population size, the U.S. comes in ninth place, having conducted 174 tests per 1,000 people. That's much lower than the per capita rate in Luxembourg at 691 per 1,000 people, the United Arab Emirates at 525 and Denmark at 268.
Moreover, while there is no gold standard for testing rates, the number of tests needed is proportionate to the number of infections in a country, says Lessler. So, if the U.S. could reduce COVID-19 transmission and new cases, then the need for high testing levels would drop.