The US Centers for Disease Control and Prevention said Thursday it had changed the way it was reporting death rates for coronavirus, and will now report the infection fatality ratio by age.
It’s all still based on approximations, and as part of the update the CDC also estimates it’s missing most cases of coronavirus in the US -- by a factor of 11.
According to the updated “best estimate” numbers posted on the agency’s website:
- 0.003% of children 18 and younger who are infected with coronavirus die.
- The fatality rate is 0.02% of people aged 20 to 49.
- 0.5% of people aged 50 to 69.
- 5.4% of people 70 and older.
Transmission time: Under the best estimate scenario, it takes about six days, on average, for people to develop symptoms after they’ve been in contact with the virus.
ICU care: Just below 24% of people under the age of 50 who are hospitalized will need ICU care, the CDC estimates. This rises to 36% of people 50 to 64, and 35% of people 65 and older.
Fatality rate for those hospitalized:
- About 2.4% of people ages 18 to 49 who are hospitalized die, the CDC estimates.
- It rises to 10% of those 50 to 64 who are hospitalized.
- And more than 26% of people over 65 who are hospitalized.
Not only are the numbers an estimate, but reports of death rates lag by weeks, the CDC said. On average, it takes about 45 days for a coronavirus death to be reported.
Asymptomatic cases: The CDC calculates that 40% of cases are asymptomatic, and that these people without symptoms are about 75% as infectious as people with symptoms, although this is “highly uncertain.”
Infection fatality ratio is one of several ways of reporting mortality rates. It’s calculated by dividing the number of deaths by the number of actual infections -- and since the true number of coronavirus infections is not known, it is by necessity an estimate.