The death rate of coronavirus, according to the World Health Organization, is 3.4%. That means that for every 1,000 people infected by the virus, 34 will die.
It has been fairly well established that, once the dust settles, the death rate will be known to be lower than 3.4% — at least in some locales. That may not be true for some of the hardest-hit regions. (In Italy, for example, the number of known coronavirus cases that have resulted in death is a whopping 7.3%.) But, for much of the world, it’s true — for one reason: not all cases of coronavirus are known.
In South Korea, where well over 200,000 people have been tested amid the world’s best response to the coronavirus, the death rate is 0.9%, much lower than the WHO’s official estimate. Why? Because by doing such extensive testing, South Korea is catching most of the cases of coronavirus that occur there (8,086, according to the latest reports). In other countries, like the United States, only the sickest people are being tested while the mildest cases go untested.
(For what it’s worth, South Korea’s death rate has risen in recent days, from 0.6% to 0.9%. That puts it in range with what most infectious disease experts predict is the actual death rate of coronavirus, between 1% and 2%.)
In the U.S., it’s likely that we’ll never know exactly what the death rate of coronavirus is. We got a woefully late start in testing, and although testing is ramping up now, there are still protocols in place for which patients should be tested and which ones should not, because there aren’t enough tests to go around. By the time sufficient numbers of tests are made available, it’s likely that the pandemic will be past its peak in the U.S.
Meanwhile, there are two examples of data coming out that make the case for a death rate lower than 3.4% — which would confirm the suspicions of many health experts and the speculation by many among the general public.
First is the data from the Diamond Princess cruise ship, which was quarantined at sea off the coast of Japan after a passenger tested positive for coronavirus. Virtually everyone on the cruise ship was tested (3,063 out of 3,711), making it an excellent opportunity for researchers to learn more about the coronavirus, how it spreads, and how it kills.
Almost 19% of the cruise ship’s 3,711 passengers were infected by coronavirus — a total of 696 cases. Of those, there were 7 deaths, or just over 1%. Again, that’s much lower than the WHO’s published death rate, and in line with what many health experts believe.
A team of doctors conducted a study of the data available from the Diamond Princess and were able to derive several other estimates, as well. These numbers have changed a bit since February 20, the data cutoff for the study. But, at that point, slightly more than half (52%) of the patients who tested positive did not display any symptoms. Of the remaining 48% who had symptoms, the fatality rate was 1.9%. Among all infected, the fatality rate was 0.9%.
So, essentially, if you remain asymptomatic (which probably means you’ll never know you had coronavirus), the fatality rate was slightly less than 1%. But among those who actually developed symptoms, no matter how mild, the fatality rate doubled, to about 2%.
This helps explain why the death rates are so high in some areas — only the sickest patients are being tested.
As health experts have warned from the beginning, data from the Diamond Princess proved that the elderly are most at risk, by far. The death rate among those 70 and older was a significant 7.3%. (But that’s still lower than scientific estimates from some nations with coronavirus outbreaks, where it’s been estimated that death rates among those 70 and older is above 10% — again, likely accounting for the fact that some older patients never develop symptoms.)
The researchers applied that data to the available data from China and concluded that the real death rate there from coronavirus was probably 1.1% among patients who developed symptoms, or about 0.5% once asymptomatic cases are added into the equation.
According to U.S. News & World Report, the overall number of coronavirus symptoms in Japan rose to 1,484 on Sunday, with 29 fatalities. That makes for a death rate of 2.0% in Japan. However, that data includes the infections from the Diamond Princess. If you extract those numbers, Japan’s death rate jumps to 2.8%.
However, Japan has only tested slightly more than 10,000 people — about 80 tests per 1 million people. That’s far more than have been tested in the U.S., about 42 per 1 million people — but also far, far below nations such as South Korea, which has conducted almost 4,900 tests per 1 million people.
Second is the increase in flu-like symptoms in the U.S. in the past week. According to the Centers for Disease Control & Prevention for the week ending March 7, cases of flu confirmed by clinical laboratories decreased for a fourth consecutive week, but flu-like illness increased slightly. Flu-like illness are cases that are not confirmed by flu tests, but include flu-like symptoms of fever, coughing or sore throat — which just happens to be the same symptoms most commonly caused by coronavirus.
There is no way to know for sure that these flu-like illnesses are being caused by coronavirus, of course. But the uptick in the number of cases, while the number of flu cases is in decline, is intriguing and makes it a reasonable assumption. Remember, the U.S. is still treating relatively few (almost no one) for coronavirus.
Currently, there are 3,244 confirmed cases of coronavirus in the U.S., and 57 fatalities. That means 1.8% of known coronavirus cases in the U.S. are ending in death. But the real death rate is likely substantially lower than that.
None of that is meant to say that coronavirus isn’t to be taken seriously. Fifty-seven deaths may not seem like a lot, especially considering over 22,000 Americans have died from flu complications this year. But keep in mind that 36 million Americans were infected by the flu, according to CDC estimates. That’s a death rate of about 0.06%. The coronavirus is just now becoming established in the U.S. Absent preventative measures, scientists estimate the disease will double its presence every four days. If 36 million Americans are infected by coronavirus, the death toll will be substantially higher than the 22,000 that have been killed by the flu.