Thread by @Dr_D_Robertson

A short thread on Infection Fatality Rates in light of the potential news of increased fatality rate of the new (UK) B1.1.7 variant, Variant of Concern VOC-202012/01.

The infection fatality rate (IFR) is the proportion of people who can be expected to sadly die if infected ...

The critical thing to know about Covid is that the IFR is *very* dependent on the age of the patient. Very dependent.

Here's a chart from @zorinaq showing the IFR (the red line) compared to 'flu (the blue line)

github.com/mbevand/covid1…

The IFR for an 85 year old may be 10%. So out of 1000 85-year-olds who catch Covid, 100 may be expected to sadly die.

The IFR for a 60 year old man may be 1%. So out of 1000 60-year-old men who catch Covid, 10 may be expected to sadly die.

The IFR for children is *very low*

In today's Number 10 press conference, @uksciencechief has indicated that the IFR for a 60-year old man for the new UK variant may now be 13 to 14 out of 1000.

Which indicates a 30-40% increase in IFR for that 60-year-old man.

The @uksciencechief has said stressed that these increases are *uncertain*.

What is not clear is whether this (uncertain) 30-40% increased IFR is across whole age range or whether certain groups are more or less susceptible.

This is *in addition* to increased transmissibility of the new variant.

Increases in transmissibility are very bad, and increases in IFR are bad.

And the UK variant is only one variant of concern.

gov.uk/government/pub…

The news of increased transmissibility and potential increase in IFR are both bad.

This is a perilous situation, and those that advocate releasing restrictions do not understand the gravity of the situation.

Here is the NERVTAG report on the UK VOC (variant of concern)

"There is a realistic possibility that VOC B.1.1.7 is associated with an increased risk of death compared to non-VOC viruses"

gov.uk/government/pub…