For those not working in epidemiology:
Omicron isn't Pac Man
It's not chasing down the few with no past infection or vaccination
Most have been infected or vaccinated in South Africa and worldwide
To spread this fast, this variant has been infecting those with some immunity
Omicron isn't Pac Man
It's not chasing down the few with no past infection or vaccination
Most have been infected or vaccinated in South Africa and worldwide
To spread this fast, this variant has been infecting those with some immunity
This changes how we quantify its risk.
It is a bit of the tortoise and the hare.
Variants that quickly infect in naive populations are like the hare. High R0
Variants that keep chugging along despite immunity may be the tortoise. High Immune Escape
Tortoise can win in the end
It is a bit of the tortoise and the hare.
Variants that quickly infect in naive populations are like the hare. High R0
Variants that keep chugging along despite immunity may be the tortoise. High Immune Escape
Tortoise can win in the end
A bit of terminology
R0: # 2ndary infections per initial infection in a naive population
Intrinsic R0 no longer alone determines spread as the world is no longer naive to COVID
Rt or Reffective describes 2ndary infections in real time in an outbreak w/immunity, behavior change
R0: # 2ndary infections per initial infection in a naive population
Intrinsic R0 no longer alone determines spread as the world is no longer naive to COVID
Rt or Reffective describes 2ndary infections in real time in an outbreak w/immunity, behavior change
R values always depend on context
Simple quantification is
R = beta*c*d
beta - transmission probability per contact
c - # contacts per day
d - duration of infectivity in days
R depends on network of contacts, reductions in beta, c, d (eg masking, vaccines, immunity, distancing)
Simple quantification is
R = beta*c*d
beta - transmission probability per contact
c - # contacts per day
d - duration of infectivity in days
R depends on network of contacts, reductions in beta, c, d (eg masking, vaccines, immunity, distancing)
From @trvrb, the best way to understand this difference is that when most immune, intrinsic R0 transmissibility and immune escape together determine spread.
Omicron, with higher immune escape (specifics still being updated) may have a much higher Rt in this immune population
Omicron, with higher immune escape (specifics still being updated) may have a much higher Rt in this immune population
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