During a Senate appropriations Feb. 25 subcommittee hearing, Chad Wolf, the acting secretary of Homeland Security, said the U.S. flu mortality rate was about the same as the current estimated global mortality rate of the coronavirus outbreak.
He made this statement during an exchange with Sen. John Neely Kennedy (R-La.) regarding what the acting secretary knew about the coronavirus, which causes a disease known as COVID-19. This shows the full discussion between the two.
Kennedy first asked what the worldwide mortality rate for coronavirus is, to which Wolf responded that it was 鈥渦nder 2%鈥 but that he would need to check with the Centers for Disease Control and Prevention to get the actual figure and that 鈥渋t changes daily.鈥 The Louisiana senator then asked, 鈥淲hat鈥檚 the mortality rate for influenza over, say, the last 10 years in America?鈥
Wolf answered: 鈥淚t鈥檚 also right around that percentage as well. I don鈥檛 have that offhand, but it鈥檚 right around 2% as well.鈥
We asked the Department of Homeland Security where Wolf鈥檚 figure came from.
A DHS spokesperson said in an email, 鈥淎s the acting secretary said in his hearing, he did not have that information on hand and refers to Health and Human Services 鈥 the federal agency in charge of the federal government鈥檚 coronavirus response.鈥
Comparing mortality rates between the coronavirus and flu seemed like an important mechanism for understanding the growing concern about the reach of coronavirus, so we decided to dig deeper to find out if these statistics hold up. We also asked experts to explain what the numbers mean in terms of risk.
Digging Into Mortality Rate Numbers
The CDC directed us to its and referred us to the for more information on coronavirus.
Christopher Mores, a global health professor at George Washington University, helped make sense of some figures. He calculated the average, 10-year mortality rate for flu using CDC data and found it was 0.1%. That 0.1% rate is frequently cited among experts, including , director of the National Institute of Allergy and Infectious Diseases.
Dr. Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security, called it 鈥渟ort of the canonical seasonal influenza mortality figure.鈥
It鈥檚 important to note that, although this percentage seems like a small number, influenza is responsible for an 30,000 to 40,000 deaths annually.
Now, for coronavirus.
According to released Feb. 17 by the Chinese Center for Disease Control and Prevention, the mortality rate for coronavirus was 2.3%. That鈥檚 based on cases reported through Feb. 11 and calculated by dividing the numbers of coronavirus-related deaths at the time (1,023) by the number of the confirmed cases (44,672) of the coronavirus.聽 (These numbers reflect the information available at the time of the secretary鈥檚 testimony.)
But this report has limitations, Mores said, including the vague way Chinese officials are defining who has been infected by the coronavirus.
鈥淲e have not been able to understand what precisely has gone on there,鈥 said Mores. 鈥淭hey have changed their case definitions multiple times. It鈥檚 murky what has gone into the case count and who has gone into being counted on cases.鈥
The WHO said in a Monday that in Wuhan, China, the city where the virus emerged, the mortality rate ranged from 2% to 4%. Officials said that in the rest of China, outside of Wuhan, the mortality rate of coronavirus is 0.7%.
Mike Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said the mortality rate in China has since risen to 0.9%.
Right now he doesn鈥檛 see a similarity in the flu mortality rate and the coronavirus mortality rate. 鈥淲e don鈥檛 have any evidence to that being the case,鈥 said Osterholm.
Mores said U.S. health officials just don鈥檛 have enough information to know whether the two mortality rates are similar. Understanding this comparison would offer a means to better understand the severity of the coronavirus. It could also help in educating the public about the novel illness.
鈥淯ntil we can gain our own experience with this virus, it鈥檚 going to be pretty squishy. So, all the numbers that you have come across here are within the range of possibility,鈥 he said. 鈥淎bsolutely, the hope is we will end up with something similar to the flu, but we just don鈥檛 know yet.鈥
Multiple experts told us that the number of coronavirus cases not just in China but worldwide has probably been undercounted because many people with the infection do not suffer serious symptoms and may not seek medical treatment. It is possible that only those who have tested positive are being counted as 鈥渃onfirmed cases.鈥
Until the case definition is expanded to include people clinicians think may have COVID-19 but who were not tested for it, they said, the total estimated number of cases will remain lower than the likely reality. But, if the number of cases widens to include those with mild symptoms who have not been tested, then the mortality rate will go down.
This is the way mortality rates are calculated for the flu, said Mores. The numbers of flu illnesses and deaths are estimates based not only on positive flu tests, but also on doctors鈥 suspicions and symptomatic diagnosis.
One key difference between the flu and the coronavirus illness, Osterholm cautioned, is that, with the flu, the population has a partially built-up immunity, whether through receiving flu shots or already having been exposed to the illness.
Mores concurred. 鈥淵ou know, the risk is this: We have a brand-new virus in a completely naive population on Earth; we鈥檙e all susceptible to it. Everyone is potentially infectable with this virus,鈥 he said. 鈥淓ven with a high transmission rate and the low case fatality rate, that still becomes a massive number of ill and fatal cases.鈥
Our Ruling
There are two ways to parse out this claim: First, is it true that the average U.S. mortality rate for flu is 2%?
That鈥檚 not true, according to data from the CDC and exchanges with multiple global health experts. On average, the flu mortality rate during the past 10 years has been 0.1%. In addition, Wolf and a DHS spokesperson admitted that the acting secretary did not have the statistics in front of him when he answered questions at the hearing about the mortality rates.
Second, is it true the COVID-19 mortality rate is similar to the flu mortality rate?
Wolf is also wrong on that account, based on the limited information currently known about the coronavirus. Recent data from the Chinese government set the COVID-19 mortality rate at 2.3%. That鈥檚 vastly different from the flu鈥檚 mortality rate of 0.1%.
Experts also said that while it鈥檚 possible the mortality rate from the new virus could come close to the flu鈥檚 mortality rate eventually 鈥 if the case definition of coronavirus were expanded 鈥 it鈥檚 too soon to make that assumption with the limited information available.
For these reasons, we rate the claim False.
Source List:
C-SPAN, Feb. 25, 2020.
The Washington Post, Feb. 25, 2020.
Email exchange with the Department of Homeland Security Office of Public Affairs, Feb. 26, 2020.
Email exchange with the Centers for Disease Control and Prevention Office of the Associate Director for Communications, Feb. 28, 2020.
Centers for Disease Control and Prevention, page last reviewed Jan. 27, 2015.
Centers for Disease Control and Prevention, page last updated Jan. 8, 2020.
Centers for Disease Control and Prevention, page last updated Feb. 14, 2020.
Centers for Disease Control and Prevention, page last updated Jan. 10, 2020.
Phone interview with , a professor of global health at the Milken Institute School of Public Health, George Washington University, Feb. 27, 2020.
Email exchange with Dr. , a senior scholar with the Johns Hopkins University Center for Health Security, Feb. 26, 2020.
Phone interview with , Regents professor and director of the Center for Infectious Disease Research and Policy at the University of Minnesota, Feb. 27, 2020.
Chinese Center for Disease Control and Prevention, Feb. 17, 2020.
JAMA, Feb. 24, 2020.
World Health Organization, Feb. 24, 2020.
Email exchange with , a professor and director of the Center for Global Health Studies at Seton Hall University and senior fellow for global health studies at the Council on Foreign Relations, Feb. 26, 2020.
Email exchange with , John Snow professor and director of the Center for Infection and Immunity, Columbia University, Feb. 26, 2020.
The Washington Post, April 10, 2018.
The Washington Post, May 10, 2018.
The Washington Post Health 202, Feb. 27, 2020.
Center for Strategic and International Studies,鈥 November 2019.
Democratic Senators鈥 Letter to National Security Adviser Robert O鈥橞rien, 鈥 Feb. 13, 2020.
Politico, Feb. 26, 2020.
Centers for Disease Control and Prevention, Feb. 26, 2020.
Politico, Feb. 26, 2020.
Politico, Feb. 27, 2020.
The White House press release, Feb. 27, 2020.
KHN Morning Briefing, 鈥淭rump To Assemble U.S. Task Force To Tackle Coronavirus; Top Health Officials Reiterate Americans Are At Low Risk,鈥 Jan. 30, 2020.