Thread by @COVID19actuary

What is known and what is still to be determined in respect of Omicron? How should we think about next steps when faced with uncertainty?

In our new blog @AdeleGroyer and Stephen Kramer summarise the current state of knowledge and consider how to respond.
covidactuaries.org/2021/12/08/omi…

The effective reproduction number, R, has risen significantly in South Africa since early November, but as @trvrb shows, this may be due to a higher R0, greater immune escape, or a mixture of the two.

https://twitter.com/trvrb/status/1466076797670363140?s=21

Initial findings suggest that Omicron *may* have less severe impacts than were seen for other variants. @MRCza states that it will take another two weeks before one can draw more precise conclusions about disease severity.

A pre-print by @SACEMAdirector concludes:
“population-level evidence suggests that the Omicron variant is associated with substantial ability to evade immunity from prior infection. In contrast, there is no … evidence of immune escape associated with the Beta or Delta variants.”

There may be a signal in a snapshot from Tshwane hospital that vaccines have been protective. However, caution is needed because of possible confounding with the age pattern of infections.

What actions should be taken when faced with uncertainty while awaiting further data? @WHO has recommended:
- enhanced surveillance and sequencing
- public health measures to reduce circulation
- increase health capacity
- address inequities in access to vaccines and treatments.

Much more detail on what we do and don’t know about Omicron is in our latest blog, available now on our new website. Thanks to @AdeleGroyer and Stephen Kramer for this useful summary.

covidactuaries.org/2021/12/08/omi…