Coronavirus | Featured Stories

By Beth Stibal |

CDC’s “Best” Estimate Shows 35 Percent of Those Infected with COVID-19 are Asymptomatic

The Centers for Disease Control and Prevention (CDC) has issued its “best estimates” on the proportion of people who are infected with COVID-19 being asymptomatic, in addition to estimates on the virus’ fatality rate.

According to the “best estimate” model, 35 percent of those infected with coronavirus are asymptomatic. The models also reflect that the fatality rate is .4 percent for those with symptomatic infections.

The models offer five scenarios. Four out of the five are based on parameter values representing the lower and upper extremes for disease severity and viral transmission of the virus. However, the CDC cautions that the values will change as more information becomes available.

In two of the worst case scenarios, the virus would be fatal for up to 1 percent of those with symptomatic infections. The range of those who are asymptomatic is 20 to 50 percent.

The models also show that between 2.8 to 4.1 percent of all symptomatic infections end up with hospitalizations, with the CDC’s best estimate putting that number at 3.4 percent.

Additionally, the “best estimate” model shows that it takes an average of six days from infection to symptom onset, and that 40 percent of the transmissions occur prior to symptom onset.

The CDC provided the following disclaimers about the information:

-Are estimates intended to support public health preparedness and planning.

-Are not predictions of the expected effects of COVID-19.

-Do not reflect the impact of any behavioral changes, social distancing, or other interventions.

The CDC’s current “best guess” is that, if there were no further social distancing or other efforts to control the spread of the virus, about four-million patients would be hospitalized in the U.S. with COVID-19, while 500,000 people would die over the course of the pandemic.

To read the full data, click here.