March 3, 2020

Editor's note: This story was updated March 4, 2020, to reflect new mortality data from the World Health Organization.

Flu activity is still widespread throughout most of the country with at least 32 million people falling ill with the flu as of Feb. 22, but mounting concerns about the novel coronavirus have some asking: Which is worse, the flu or the coronavirus?

Flu activity so far

According to Friday's Weekly Influenza Surveillance report from CDC, 48 states were experiencing widespread flu activity in the week ending in Feb. 22, while Oregon was experiencing regional flu activity and Hawaii and Washington, D.C. were experiencing local flu activity.

By some indicators, this season is worse than last. For example, the data shows the cumulative hospitalization rate for the flu is 52.7 per 100,000 people this season, compared with 33.5 per 100,000 at the same point last season.

According to CDC, this year's flu season has led to at least 14 million medical visits; 310,000 hospitalizations; and 18,000 deaths. In addition, CDC found that the percentage of outpatient visits for influenza-like illness decreased to 5.5% in the week ending Feb. 22, down from 6.1% in the week ending Feb. 15. The national baseline for those visits is 2.4%.

This flu season has been especially bad for children, according to CDC. The latest CDC report shows 125 pediatric deaths have been reported as of Feb. 22. The cumulative hospitalization rate for children ages four and under is 80.1 per 100,000 people this season.

Which is worse: the flu or the coronavirus?

While the 2019-2020 flu season isn't letting up yet, it's largely been overshadowed by the  novel coronavirus, known as COVID-19. Since making headlines in December 2019, COVID-19 has infected 89,800 people and killed 3,056 people worldwide.

As public health experts learn more about COVID-19, many are asking, which is worse: the flu or COVID-19?

Based on the latest data, the coronavirus appears to be deadlier.

World Health Organization (WHO) officials on Tuesday estimated that the global mortality rate for new coronavirus infections, known as COVID-19, is about 3.4%, which is higher than the 2% officials previously had reported.

WHO Director General Tedros Adhanom Ghebreyesus said the 3.4% mortality rate for COVID-19 is higher than the flu's global mortality rate. "Globally, about 3.4% of reported COVID-19 cases have died. By comparison, seasonal flu generally kills far fewer than 1% of those infected," he said. However, WHO spokesperson Margaret Harris said COVID-19's updated mortality rate is a "crudely calculated" snapshot based on the growing number of cases outside of China and is expected to "change over time, and vary from place to place."

Public health experts have warned that discrepancies in how different countries report individual cases and determine how contagious the new coronavirus is makes it hard to determine a precise global case count, and as a result, we don't yet have an accurate mortality rate. For instance, research published last week in JAMA suggests the mortality rate for the virus currently is around 2%, while a report published Friday in the New England Journal of Medicine (NEJM) estimated the mortality rate is 1.4%.

According to an editorial published in NEJM by Anthony Fauci and Clifford Lane from the National Institute of Allergy and Infectious Diseases, and CDC director Robert Redfield, the true death rate for the coronavirus could end up being below 1%, which would make it similar to the death rate seen in a severe flu season. 

Early data also suggested the new coronavirus may be more contagious than the flu, the Times reports. The latest NEJM study suggests each coronavirus patient on average infects 2.2 other people. In comparison, research has shown each flu patient on average infects 1.3 other people. However, Tedros explained that the new coronavirus does not transmit as easily as the flu. So why does it appear to be more contagious? He explained that  "many people globally have built up immunity to seasonal flu strains, [while] COVID-19 is a new virus to which no one has immunity." That means individuals are more likely to contract COVID-19 than they are the flu, even though influenza viruses are more easily spread (CDC Weekly U.S. Influenza Surveillance Report, 2/28; CDC "Flu View," accessed 3/2; CDC Preliminary In-Season 2019-2020 Flu Burden Estimates, accessed 3/2; Schumaker, ABC News, 2/14; Wesner Childs, Weather.com, 2/14; Bean, Becker's Hospital Review, 2/28; Grady, New York Times, 2/29; Weixel, The Hill, 3/3; New York Times, 3/4).

Topics