CDC: Coronavirus fatality rate could be as low as 0.26%

New estimates released by the Centers for Disease Control and Prevention indicate that COVID-19 may have an infection fatality rate as low as 0.26%, a number that is double the seasonal flu but significantly lower than earlier estimates. 

Determining the infection fatality rate of the illness has been a critical goal of scientists around the world since the discovery of the disease in late November. Infectious disease experts were shocked at the end of last year and into 2020 at both how quickly the disease spread and how many of those who became ill ultimately died. 

In early February, modelers at Imperial College London estimated that around 1% of infections of COVID-19 would ultimately result in death. That number, which is about 10 times higher than the seasonal flu, shocked much of the world, including the U.K. government and most of the 50 U.S. state governments, into shutting down major swaths of their economies and placing many of their citizens under strict stay-at-home orders. 

Those high estimates have persisted in recent months. In early March, White House adviser Anthony Fauci said the disease was "10 times more lethal than the seasonal flu." The Trump administration would eventually go on to urge temporary severe mitigation measures across the United States, including pulling children from school, limiting gatherings to fewer than 10 people, and refraining from eating at restaurants and bars. 

Numbers have dropped over time

Over the past several weeks, however, the estimates of the fatality rate have brightened considerably. Driven in part by large-scale serology tests, which have consistently indicated that the disease is far more widespread and consequently less deadly than it initially seemed, scientists have lately been revising their fatality rate assumptions down significantly. 

The Centers for Disease Control and Prevention this week continued that trend, releasing a list of what it called "COVID-19 Pandemic Planning Scenarios." That document laid out five different scenarios for public health experts and government officials to consider, one of which the agency called its "current best estimate" of the parameters of the viral pandemic. 

That scenario states that the overall fatality rate of infections that show symptoms is around 0.4%. Yet the CDC says it estimates that around 35% of all infectious are asymptomatic, meaning that the total infection fatality rate under the agency's "best estimate" scenario is around 0.26%, or a little more than twice that of the seasonal flu. 

Those numbers, while much lower than the earlier estimates that drove the lockdowns, still represent a significant number of deaths, as well as a significant burden on local healthcare systems that can become overwhelmed by COVID-19.

The CDC estimates that as many as 60,000 Americans die of the flu in an average year, meaning—if the agency's current estimates are correct—the U.S. could still see tens of thousands of more deaths before the fatalities begin to recede. 

The disease itself also appears to spread more easily than seasonal influenza, meaning even if COVID-19's infection fatality rate were equal to that of the flu, the total number of deaths from it would still likely exceed that of influenza simply because it would infect more people. 

Yet the lower numbers, if accurate, are an encouraging sign that the disease is not as lethal as was earlier estimated. Policymakers and public health officials, of course, can only act on the best data available to them—and much of the data over the past few months has been encouraging, suggesting the way out of the pandemic may not be as difficult as once thought.