Graham Medley – A rambling mind

The Kraken Wakes*

Chart 318 for scenario UK_1246 with adult vaccinations, and vacs for 5-11 year-olds from April 1st 2022. 24th February NPI reduction = -79.64%. Omicron BA.1 transmission k11 = 6, BA.2 k11 = 8, BA.4-5 transmission k11=11, Kraken XBB.1.5 transmission k11=15. All k2hl = 5.1. Omicron BA.1 var_eff = 25/50/70%. Omicron BA.2 var_eff = 70/85/95%. Omicron BA.4/5 var_eff = 25/50/70%. Kraken XBB.1.5 var_eff = 25/50/70%. Omicron BA.1 fSS=3% and fMORT=1.5%. Omicron BA.2 and BA.4-5 fSS=3% and fMORT=1.5%. Kraken XBB.1.5 fSS=3% and fMORT=1.5%. Model outcomes to December 3rd 2023. Reported active cases and deaths to 7th Feb 2023. Serious cases for 7 variants.

I have continued to improve and run my Coronavirus model daily. The code for the model is now at version 172, and I have added a dataset to represent the variant XBB.1.5, known informally as “Kraken”. The fit of the model to reported deaths is good. I explore in the article the behaviour of Modelled vs. Reported Active Cases.

Omicron BA.2, vaccination for 5-11 year-olds, and the honeymoon period

Chart 318 for scenario UK_701 with adult vaccinations and 5-11 vacs from April 1st 2022. 17th May 1.8% ,19th July 1%, 1st Sep 2%, mean NPI relaxations and 30th Nov +2% and 10th Dec +3% additional NPIs. Omicron v4 transmission k11 = 6, BA.2 v5 k11 = 8, var_eff = 25/50/70%, fSS 7% and fmort 1.05%. Model outcomes to December 3rd 2023. Reported active cases and deaths to February 19th 2022. Serious cases for 5 variants.

I haven’t needed to make significant updates to my Coronavirus model for a while, because it has been working well.
The original Omicron variant morphed into the new BA.2 variant, and although it seems no more dangerous than its predecessor, it is thought to be between 33%-50% more transmissible. I have assumed the lower value of 33% more transmissive for this post.
I have added Omicron BA.2 as fifth variant v5 to my model, with 8 times the transmissibility of Delta, compared with the original Omicron variant v4 in the model, at 6 times the Delta transmission rate.