Vaccine – A rambling mind

What are UK Government advisers seeing?

Recent variants with their identifiers, lineage, source country if known, total cases, and new cases since May 12th: source gov.uk

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.

Why the UK Government is worried about new variants

Chart 18 for scenarios UK433 & UK439: v3 transmission k11 = 1, comparing var_eff and fss fmort effects. Modelled 800 day outcomes to April 12th 2022 compared with reported deaths to May 23rd. Serious cases for all variants, with 2021 NPI relaxations up to June 21st 2021.

NPIs, variants and vaccine models

Chart 17 model output for deaths, active cases and Seriously Sick to 800 days. 2nd virus variant from September 23rd, day 235. 3rd variant from January 1st 2021, Day 335. 250k vacs/day from January 1st (day 335) and 400k vacs/day from February 1st (day 366) and thereafter. 15% NPI reduction on March 7th, model Day 401.

This paper reports some parametric Coronavirus model runs I have made that compare, in particular, how the UK vaccine programme allows some NPI relaxation compared with a case with no vaccination. The outcome is that the vaccine programme in the UK has the potential to reduce the imposition of NPIs on March 7th by about 15%, without costing lives, this being the next time we in the UK are due for a major NPI review, potentially involving the return of schools at around March 7th.

The end of the beginning*

Chart 13 model outputs to 450 days, April 27th, 2021, no vaccinations compared with a 3-phase vaccination programme, as at December 1st

Now that it seems clear that a vaccination programme in the UK might start as early as next week, I have re-run my Covid-19 vaccination model for the UK, updating the November 25th scenarios (which begin on January 1st 2021) to reflect some potential UK outcomes.

Modelling of vaccine strategies

Comparative vaccination charts for the UK to 800 days. Continuation of current NPIs on the left; and an graduated vaccine intervention on the right from January 1st 2021

In my most recent post on November 18th, about updating my Coronavirus model to handle the impact of vaccines, I gave some examples of how case numbers, and more specifically death rates might be improved for the UK through a vaccination programme. Now that there seem to be several vaccines imminent, with efficacies ranging from 70% (Astra-Zeneca/Oxford) through 90% (A-Z/O via a different inoculation regime, and Pfizer), to 95% (Moderna) and several others in the mix, I explore some sensitivities in more detail, and also apply the model to the USA.

Vaccine, vaccine, vaccine, vaciiiine,…(don’t refuse it, just because you can)

New 8-compartment model flowchart with additional vaccination compartment V

In the news today, I read that Dolly Parton had given $1,000,000, through her Covid-19 Research Fund, to help fund the Moderna vaccine development. As The Times newspaper reported, this – erm – somewhat trumps the White House contribution to public safety. In her honour, Ryan Cordell composed and performed this ditty. The timing neatly coincides with the work I have been doing to incorporate vaccination into my Coronavirus model, and to that end I have been researching ways of modelling vaccination. I have made some appropriate changes, and run some model options for different vaccine efficacy; vaccinations per day; and date of starting the vaccination programme.