WASHINGTON – President Donald Trump said Tuesday that the United States' coronavirus mortality rate is "one of the lowest of any country in the world."

Dr. Deborah Birx, who leads the White House coronavirus task force, echoed the claim at a news briefing, saying the United States had "one of the lowest mortality rates in the entire world."

Neither Trump nor Birx cited a specific statistic or study to support their claims, but both used the mortality rate metric as evidence America is making progress in fighting coronavirus.

Here's where the U.S. ranks, according to data from John Hopkins University:

The U.S. has the 33rd-highest mortality rate, measured as deaths divided by total cases, out of the 134 countries tracked by Johns Hopkins. That means more than 100 countries have lower mortality rates than the U.S., although many of those countries reported comparatively few cases.

When compared only to the 10 countries with the most cases, the U.S. ranks as the second-lowest mortality rate as a percentage of total cases. That means eight of those countries hit hardest by the coronavirus have higher mortality rates than the U.S.

only to the 10 countries with the most cases, the U.S. ranks as the second-lowest mortality rate as a percentage of total cases. That means eight of those countries hit hardest by the coronavirus have higher mortality rates than the U.S. The U.S. ranks 12th-highest in the world when it comes to deaths per 100,000 people.

When mortality is measured per 100,000 people among the 10 countries with the most cases, the U.S. ranks seventh, with Iran, Germany, and China reporting lower numbers of deaths per 100,000 people.

Experts said Trump's comments glossed over the fact that under several metrics, the U.S. mortality rate is worse than that of many other countries. However, they cautioned that the lack of testing in the United States could lead to an undercounting of overall COVID-19 cases. If the total number of cases is actually higher, that would mean the current data might be overstating the death rate.

As of Wednesday, the United States had a 5.4% mortality rate based on a percentage of overall cases, according to the Johns Hopkins data.

With the 33rd-highest rate in the world, the U.S. rate exceeds countries like Canada (4.8%), Portugal (3.6%), and Germany (3.4%).Among those countries with higher death rates are Belgium (14.6%), Italy (13.4%) and the United Kingdom (13.4%).

Among those 10 countries hit hardest by the coronavirus, eight countries have a higher mortality rate based on a percentage of overall cases – with countries like Belgium (14.6%), Italy (13.4%), and France (13.1%) reporting higher mortality rates than the U.S., according to the Johns Hopkins data. Only Germany (3.4%) has a lower mortality rate among those 10 countries.

The White House declined to comment, but an administration official speaking on the condition of anonymity pointed to the per capita mortality rate in the United States as "lower than most major Western countries and China."

The Department of Health and Human Services did not respond to a request for comment from USA TODAY asking for clarification on the president's comments.

Trump made that point in Saturday's coronavirus task force briefing, when he said that "on a per capita basis, our mortality rate is far lower than other nations of Western Europe, with the lone exception of possibly Germany. This includes the UK, Switzerland, Belgium, the Netherlands, Italy, France."

The United States has about 13.71 deaths per 100,000 people, or the 12th-highest rate among the 134 in the Hopkins data, meaning only 11 countries have higher mortality measured on a per capita basis.

Here's what the Johns Hopkins data said Wednesday about the nations Trump mentioned in the Saturday briefing:

Germany: 6.07 deaths per 100,000 people

United States: 13.71 deaths per 100,000 people

Switzerland: 17.35 deaths per 100,000 people

Netherlands: 22.80 deaths per 100,000 people

United Kingdom: 26.14 deaths per 100,000 people

France: 31.09 deaths per 100,000 people

Italy: 40.79 deaths per 100,000 people

Belgium: 52.51 deaths per 100,000 people

Among those 10 countries hardest-hit, the U.S. ranks fourth-lowest in terms of deaths per 100,000 people. Just Germany (6.07), Iran (6.48), and China (0.33) have lower rates. Italy (40.79), Spain (45.55) and Belgium (52.51) have higher rates.

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Johns Hopkins University researchers note that mortality statistics differ among countries in part because of differences in testing, the demographics of other countries, characteristics of health care systems, and other factors.

Why exactly death rates in some countries like Germany and South Korea have been lower is still a matter of debate, especially as efforts to address the pandemic are ongoing, said Michael Gunn, a professor in immunology at Duke University School of Medicine.

Countries like Germany had a "very aggressive testing program," which allowed them to detect coronavirus and institute therapies for patients "before things got bad," Gunn noted.

In the United States, "we may just be catching people much later in the disease course," he said, and as a result, the United States' "lack of testing" means "we don't know how many people are truly infected," Gunn said.

As a result, "no one can say" that the United States has one of the lowest rates in the world, he said.

Additionally, in countries like Italy, "where the number of patients requiring hospitalization or critical care has overwhelmed the medical system, we have seen marked increases in mortality," Gunn said.

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University of California-Irvine Division of Infectious Diseases Chief Donald Forthal told USA TODAY that Trump's statement about the U.S. having one of the lowest mortality rates would be wrong based on current data, but the data was "raw and inaccurate" because of issues with the "availability of testing."

There were "lots of undocumented cases for every documented case," which would make the calculation of deaths as a percentage of total cases "difficult to ascertain."