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.
Category Archives: Efficacy
They think it’s all over – but it isn’t
In this article, I present a few variations of the current model to illustrate some outcomes depending on different assumptions about the current dominant variant, Omicron BA.2; they are fairly consistent in their forecasts over the 1400 day period of the model, from the outset in February 2020 to December 2023, and show that as NPIs are removed, vaccination is what keeps us safe.
A first 2022 Omicron update
While it is still very early days, both in the New Year of 2022 and also for the Omicron variant, this post adds to my recent 19th December update with a summary of further runs of my model for higher transmissions settings. Last time I ran options up to three times the transmission rate of the Delta variant, and I have now looked at transmission up to five times the Delta rate.
Omicron modelling update
I have run updates to my model for lower and medium vaccine efficacy to Omicron, and lower, medium and higher virulence and mortality, and continue to compare with reported data. While evidence is still in short supply, nothing has firmly contradicted the impression that Omicron is highly transmissive, as well as being possibly less virulent.
Just as we thought it was safe to go back into the water
Omicron is feared to have higher infectiousness than the Delta variant, with even greater concerns should it turn out to cause more severe symptoms, higher mortality, and possibly worst of all, if it were able to evade current Covid-19 vaccines. I have made some parametric runs of my model to assess the possible effects.
Pandemic modelling review
Vaccination has somewhat stabilised the SARS-Cov-2 pandemic in the UK. I summarise the capabilities that I have found necessary and useful in modelling the behaviour of the pandemic; successive variants, different population age-groups, the effect of Government NPIs, and vaccinations.
Booster jab matters
Having just had my 3rd Covid jab, the “booster” jab, it provoked a few thoughts about that, my Coronavirus model, and the wider scene. I had incorporated multiple jabs into my UK model some time ago, and multiple phases for inoculation volumes to cope with the first and second jabs. I am taking this opportunity to report briefly on model outcomes for waning immunity in the context of booster jabs.
“Freedom Day”, multiple vaccinations and the Delta variant
In this post, I run a development of my model which includes immunity waning (at a 150 day half-life), vaccine hesitancy by group, multiple vaccine inoculations (representing the typical two jabs required by most vaccines for best immunity) and also the possibility of vaccinated people not only to become infected, but also to pass on the virus even if not infected themselves.
Delta variant impact on June 21st easing – delay or reduce?
Having explored what pandemic advisers might be seeing and highlighting to decision-makers in Government, I run scenarios with different settings for the planned June 21st relaxation of lockdown, the last in the series of relaxations over the first half of 2021, following the January 3rd lockdown. These model scenarios show examples of what the relative consequences of the June 21st relaxation as planned, versus four other options:- cancellation of the June 21st step altogether, two different delays, of 28 and 56 days, and lastly a 50% reduction in the scope of the June 21st relaxation.
What are UK Government advisers seeing?
I have developed some model scenarios that show examples of what might be behind expert advice on the caution required with new SARS-Cov-2 variants. The scenarios indicate the importance of the UK vaccine programme, as we face variants with potentially different characteristics of transmission, severity of infection and responsiveness to vaccines. Understanding those variant characteristics is vital for projections.