(Reuters) – Global deaths from COVID-19 have reached 1 million, but experts are still struggling to understand a crucial metric in the pandemic: the death rate – the percentage of people infected with the pathogen who die.
Here’s a look at the issues surrounding a better understanding of the COVID-19 death rate.
How is the mortality rate calculated?
A true death rate would compare deaths to the total number of infections, a denominator that remains unknown because the full extent of asymptomatic cases is difficult to measure. Many people who become infected simply have no symptoms.
Scientists said the total number of infections is exponentially higher than the current number of confirmed cases, now at 33 million globally. Many experts believe the coronavirus likely kills 0.5% to 1
Researchers have begun to break down that risk by age group, as evidence shows that young people and children are far less likely to get serious illness.
“The death rate for people under 20 is probably one in 10,000. Over the age of 85, that’s about one in six, ”said Dr. Christopher Murray, director of the University of Washington’s Institute for Health Metrics and Assessment in Seattle.
What is a “case death rate”?
There has been an apparent decline in death rates when measured against the number of new infections confirmed by coronavirus tests. In places like the United States, the “death rate” dropped dramatically from 6.6% in April to just over 2% in August, according to Reuters statistics.
But experts said the decline was largely driven by more widespread testing than in the early days of the pandemic, detecting more people having mild illness or no symptoms. Improvements in treating the seriously ill and in protecting some of the high-risk groups are also attributed to improved survival.
“We are much more aware of the potential complications and how to recognize and treat them,” said Dr. Amesh Adalja of the Johns Hopkins University Center for Health Security in Baltimore. “If you are a patient who gets COVID-19 in 2020, you would much rather get it now than in March.”
What does this mean for individuals and governments?
This highlights the need for continued vigilance as some countries begin to experience a second wave of infections.
For example, researchers in France estimate that the country’s case death rate decreased by 46% by the end of July compared to the end of May, driven by increased testing, improved medical care, and a higher percentage of infections occurring in young people, who are less likely to get serious illnesses.
“We are now seeing a new increase in admissions and registrations in intensive care (intensive care unit), which means that this discrepancy is about to end,” said Mircea Sofonea, a researcher at the University of Montpellier in France. “We will have to understand why.”
Reporting by Deena Beasley; Additional reporting by Matthias Blamont in Paris; Editing by Will Dunham