UK Covid Modelling

As of 1st December 2022

Current Covid-19 status in the UK: R = 1.11 


(number of hospital cases: increasing sharply)

As part of our approach to testing our simulation skills within the company (and part of a service we provide to outside agencies), we apply our FluidFlowEngine tool to everyday concerns, from public health, to renewable energy sources and transport simulation.

Dynamic modelling comes in many forms, and testing your abilities in a real-world context is a key part of what we try to do.

Here, for example, is our ongoing calculation of R (the reproductive number of COVID-19) in England, during 2020-22:

Estimated R in England

When R is below 1.0, then the pandemic is under control in England. When R is above 1.0 then the epidemic is spreading.

The following graph is the result of a real-time R number calculation in England during the coronavirus pandemic.

The latest UK government SAGE (Scientific Advisory Group for Emergencies) figure should be available here, so you can make your own assessment as to the accuracy of our model. Also note that SAGE published values tend to lag behind our assessment by up to 5 days.

For the last seven days that data was available, the R number in England was calculated to be:​​​​​​​​​​   ​​​​​

​​​​​​​​​​​​​​​​​  ​​​              ​    ​  ​​​​            ​​ ​​                   ​          ​​​​    ​       ​​    ​​​​​​​​ ​​  ​ ​​  ​  ​​​​​      ​    ​   ​     ​ ​       ​​     ​ ​  ​  ​​ ​  ​​    ​ ​       ​​     ​             ​​​      ​     ​​​​​​​     ​  ​​​         ​    ​​​ ​     ​​    ​  ​   ​          ​      ​ ​ ​​​​​   ​  ​  ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

  • 22 Nov        1.01

  • 23 Nov        1.01

  • 24 Nov        1.02

  • 25 Nov        1.02

  • 26 Nov        1.02

  • 27 Nov        1.07

  • 28 Nov        1.11                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                

The historical R number data since 1 April 2020 can be downloaded here

*** Whereas the "Delta" variant of COVID-19 was largely being spread through the unvaccinated population, the "Omicron" variant can also spread through those who have had two or three jabs already (particularly if those were Astra-Zeneca injections, with the last more than six months ago). It is entirely possible to be infected twice with Omicron and previous infection with Alpha, Beta or Delta offers no immunity against infection with the latest Omicron strain BA.5, which is the most prevalent COVID strain in the UK in the summer of 2022. Please be careful out there. This has not gone away, and we still have the 2022-23 winter to come, so this should be "the good time". If a new variant emerges in the next six months, we could be in very tricky position. ***

A 4th booster jab is being developed which will provide enhanced immunity to Omicron BA.5. Please wait for that to be announced, and when it is, take that jab up immediately.

To protect yourself and those around you, please keep fully vaccinated (and be prepared for a regular, variant-specific booster jab, prior to every winter season for the next few years).


A few pieces of data:

  • 1st Wave of the COVID-19 pandemic (Feb-Apr 2020):

       The Covid-19 pandemic arrived in the UK sometime before February 2020.​

  • The end of the 1st Wave and the first UK National Lockdown:

       England entered its first National Lockdown on 23rd March 2020.

       England had an R less than 1.0 between 11th April and 8th August 2020.

       The lowest R that England went down to during the 2020 summer lockdown was 0.64 in July 2020.

  • 2nd Wave of the COVID-19 pandemic (Sep 2020-Jan 2021):

       It was clear (with > 95% probability) that the pandemic was accelerating again on 5th September 2020.

       This signalled the emergence of a second Covid-19 wave in the UK.

       However, the UK Government didn't lockdown again until 5 November 2020.

       The peak R in England during the second wave (in September 2020) was 1.88.

       The R in England dropped below 1.0 for a second time on 20 November 2020.

       The lowest R that England went down to during the second lockdown was 0.86 in November 2020.

       And rose back above 1.0 again on 5th December 2020.

       On 3rd January 2021 it was clear that the pandemic was accelerating again, and a third National Lockdown was required.           The UK Government announced a new National lockdown on 4th January 2021, to start immediately on 5th January.

       The peak R in England during the latter part of the second wave (in January 2021) was 1.39.

       The R in England dropped below 1.0 for a third time on 18th January 2021 and remained below 1.0 until 19th May 2021.

       The lowest R that England has seen in 2021 was 0.69 on 5th March 2021.  

  • 3rd Wave of the COVID-19 pandemic (May 2021-present day):

       In England, we are currently experiencing a prolonged third wave due to the Delta variant and now, the Omicron variant of         the virus. There have been at least six peaks in virus transmission in the UK since May 2021.

       The lowest R that England has seen in 2022 was 0.71 on 3rd November 2022.

       For the unvaccinated, the Omicron variant is still dangerous. You are 20 times more likely to be in a hospital ICU                           with Omicron if you are unvaccinated, than if you have had 3 jabs. Omicron is only 11% less deadly than Delta for the                 unvaccinated individual. The difference is that with a booster jab, you are much less likely to require hospitalisation.                     Reports will indicate that Omicron is less serious, but that is entirely because the majority of potentially vulnerable                       individuals are treble jabbed and therefore the illness is likely to be milder for them (in general). Having had Covid-19 in             the past does not prevent you catching it again, and long Covid is still a significant concern.


       We strongly recommend you do not spend time in large crowds of strangers in enclosed indoor spaces without                         ventilation, and as a matter of extreme priority get a fourth (booster) injection when it becomes available later this year             (expected to be October-November 2022).

Please remember, meeting people outside has always been generally fine: Covid-19 is an airborne disease who's severity depends on the amount of virus you breathe in. Covid-19 builds up gradually in an enclosed space, and good ventilation is key.

As you might expect, we routinely model aerosol and droplet transmission, and are involved with a very detailed project comparing closed-room and open, ventilated environments. Those results are provided for academic and Government use, and published separately

If you need any further information, please contact