Yesterday’s post took note of two significant changes in covid hospitalization trends over the past two months:
- Daily hospitalization rates have dropped by two-thirds.
- The inpatient population includes relatively more adults aged 18-49 and fewer aged 65+.
As with hospitalizations, the daily covid death rate has dropped by two thirds over the past two months. Has the age demographic for those who die from the virus also shifted downward? Provisional death counts from the CDC say no.
- In late April I tallied the cumulative covid deaths by age. People under 55 years old comprised 8% of all those who had died, while those 65 and above accounted for 79% of the deaths.
- For the week of June 13-20 the under-55 sector accounted for 8% of the deaths; those 65 and above, 79%.
So, while the inpatient population has been getting younger since the peak of the epidemic, there’s been no change in the age demographics in the death counts. What can be inferred?
Death is a hard endpoint, not substantially distorted by changes in testing or hospital admission practices. Because the age demographics of death haven’t changed, it’s likely that the demographics of infection haven’t changed either. During this initial phase of US reopening, with younger people returning to work and to parties and so on, there’s likely been no substantial downward shift in the average age of people getting infected.
Because the age demographics for death and infection rates haven’t changed, the two-thirds decrease in deaths over the last two months probably reflects a two-thirds decrease in infection rate across all ages.
The US age-adjusted estimated mortality rate of 0.6% still stands.
Because the age of the inpatient covid population has decreased substantially while the death demographics haven’t changed, it’s likely that hospitals are admitting a greater proportion of younger adults whose symptoms are less severe, and so who are less likely to die from the virus.