Thread by @yaneerbaryam

Comment on the Infection Fatality Rate:

During much of this pandemic articles have been written about the Infection Fatality Rate (IFR). However, for diseases where multiple infections are possible, the single infection fatality rate is not an indicator of fatality...

1/

..rates because deaths accumulate from multiple infections of an individual.

The reasons that multiple infections may occur even though there is a standard model of immunity after infection are:

2/

(1) the disease is defeated by the innate rather than the adaptive immune system so no change in the immune capability arises from the infection

(2) mutations of the virus occur that reduce the effectiveness of immunity

(3) decay of memory of the adaptive immune system

3/

(4) weakening of underlying physiological health (for example co-morbidities caused by the disease itself increase risk of subsequent disease severity and death)

(5) establishment of reinfection vulnerability by the infection due to changes in, e.g., lung microstructure.

4/

Multiple studies show death and hospital re-admissions are high months after discharge. And reinfection/ variants/ waning will reset things for an as yet undetermined proportion of the population (or at a rate over time). @adamhamdy

5/

Additional notes: Fatality rates do not include the effect of loss of quality of life through long covid, and the disease itself including inability to breathe.

6/