Mar. 31, 2020 -- The fatality rate from COVID-19 is not as high as experts have reported, according to a new analysis published Monday in The Lancet Infectious Diseases. But the infection is still much deadlier than the 2009 H1N1 flu pandemic, and the risk rises sharply with age, the researchers say.
And the rate may not hold true for other countries, which vary in how they are responding to the virus and in hospital resources.
In the new analysis, the death rate in confirmed COVID-19 cases is estimated to be 1.38%, while the overall rate, which includes estimated unconfirmed cases, is calculated at .66%.
Researchers from Imperial College London and other institutions produced the new estimates from an analysis of 70,117 laboratory-confirmed and clinically-diagnosed cases in mainland China, along with 689 positive cases diagnosed among people evacuated from Wuhan, China, on repatriation flights.
Since the outbreak began in December, many estimates of the fatality rate have been calculated and reported. The CDC, World Health Organization, and others have reported rates of 3.4% overall, and less than 1% in certain age groups.
COVID-19 Death and Hospitalization Rates
The new analysis confirms earlier studies showing that both rates of death and hospitalization vary by age and increase with age. Children are least likely to die, with death rates in confirmed cases of less than 1% in newborns to 9-year-olds. That rose to 4.28% in people 70 and older, and to 7.8% in people 80 years and above.
While 11.8% of infected people in their 60s were estimated to have symptoms severe enough to need to be hospitalized, 16.6% of those in their 70s did. By age 80, 18.4% needed to be hospitalized.
Least likely to need hospitalization were 10-to 19-year-olds, with a 0.04% rate. Just 1% of people in their 20s and 3.4% who are 30-39 needed hospitalization. At ages 40-49, hospitalization rates were 4.3%, but nearly doubled, to 8.2%, for 50- to 59-year-olds. To estimate the odds of needing hospitalization, the researchers looked at 3,665 cases from mainland China.
That analysis shows that most people do recover, even with severe symptoms. But age matters. "There might be outlying cases that get a lot of media attention, but our analysis very clearly shows that at age 50 and over, hospitalization is much more likely than in those under 50, and a greater proportion of cases are likely to be fatal," researcher Azra Ghani of Imperial College London said in a statement.
Jeanne Marrazzo, MD, director of the University of Alabama at Birmingham's Division of Infectious Diseases, says the mortality rates for people 70 and older were concerning. She was not involved in the analysis but reviewed it.
"Even though younger people clearly do better in terms of recovering, their rates of hospitalization are notable since so many of them were infected," she says. Although they were likely discharged and recovered, they contributed to a significant strain on the health care system, she says.
The estimates are needed to provide realistic planning for the other hard-hit countries, Marrazzo says.
But those estimates might not hold true for other areas. The rates of death from the new coronavirus may vary from country to country, due to differences in policies about prevention, control, and mitigation, says to Shigui Ruan, PhD, a professor of mathematics at the University of Miami, Coral Gables. He wrote a comment to go with the analysis but was not involved in it.
"Death or survival rates really depend on how well the country has been prepared, and the public health systems," he says. He credits China for the early ''lock down" of residents.
Another key, he says, is that ''China sent 40,000 health care workers to the province where they had the problem, and that helped dramatically." And even though the fatality rate is low for younger people affected with COVID-19, it's still much higher than that of seasonal flu. For people ages 20-29, death from COVID-19 is 3 times higher than for seasonal flu, he says.
More Data on Death, Recovery Time, Health Concerns
In the analysis, the average time from when a person displayed symptoms and died was under 18 days, the researchers found when they evaluated 24 deaths in China’s Hubei Province.
To estimate average recovery time, the researchers looked at data from 2,010 international cases, including 169 people who recovered. The average time for recovery and hospital discharge was a little over 22 days.
While previous studies have found that underlying health conditions -- things like high blood pressure, diabetes, heart disease, cancer, and respiratory illnesses -- boost the risk of severe disease and death from COVID-19, the researchers say they could not factor in the effect of these conditions because they lack individual-level data.
Editor’s Note: This story was corrected to say that COVID-19 is three times as deadly as flu, not 33, after a researcher clarified the numbers.