Tag Archives: Coronavirus

Implications of the R0 Reproduction Number in an unconstrained Delta variant environment

In my April 8th 2020 post about the R0 reproduction number and the use of SIR models to model the pandemic, I developed a chart which predicted the proportion of the population uninfected by the end of an unconstrained pandemic.

That chart allowed for an R0 up to 3, but the Delta variant that arrived in the UK a year later, in April 2021, has an R0 far higher than the original, possible 2.5 times as high, as much as R0=7, perhaps.

I have added to the scope of that previous post to develop a chart allowing R0 up to 7..

“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.

Tuning the age and vulnerability model

In my latest post on March 26th I described a new Coronavirus group model, based on work I had done as a UK case study in support of Prof. Alex de Visscher’s paper, in conjunction with Dr. Tom Sutton, on “Second-wave Dynamics of COVID-19: Impact of Behavioral Changes, Immunity Loss, New Strains, and Vaccination” which has now been published for peer review as a pre-print on Springer’s site at https://www.researchsquare.com/article/rs-195879/v1. I have now added the latest UK vaccination progress figures, and the UK Government’s announced intentions for the near future regarding Non Pharmaceutical Interventions (NPIs). I have also updated mortality and infection characteristics for the four different population groups in the model.

Age and vulnerability related Coronavirus modelling

In my most recent post on February 12th, I described modelling work I had done in support of Prof. Alex de Visscher’s paper, in conjunction with Dr. Tom Sutton, on “Second-wave Dynamics of COVID-19: Impact of Behavioral Changes, Immunity Loss, New Strains, and Vaccination” which has now been published for peer review as a pre-print on Springer’s site at https://www.researchsquare.com/article/rs-195879/v1. I have now added vaccination and multiple variants I had already added to our previous model into the new grouped population model, and this blog post reports on progress with that new model.

Concurrent Coronavirus two variant modelling

I present an analysis of the pandemic situation in the UK, with two Coronavirus variants present since December 16th, and sensitivities to different New Year 2021 Non Pharmaceutical Interventions (NPIs), but always with the background of vaccine dispensing, which started in the UK on December 8th.

Exploring the possible impact of the new variant coronavirus

I cautiously welcomed “the end of the beginning”, and events since then have borne out the need for caution, with the discovery of a mutant variant of the SARS-Cov-2 virus (denoted VUI-202012/01) which seems to have a much greater transmission rate, as much as 70% more than the strain of SARS-Cov-2 we have seen previously in the UK. I have developed a further version of my Coronavirus model which now includes not only intervention capability but also a vaccination module, as reported before, and now the ability to add further virus strains with different transmission characteristics.

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

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.

Make America well again

I look at the impact of a postulated change in the timing of further measures to control the Covid-19 epidemic in the USA, against a current background of rapidly increasing daily case numbers and deaths. I also show an updated projection for the UK, both compared with Worldometers forecasts