"Our aim is to try and reduce the peak, broaden the peak, not to suppress it completely, also because most people, the vast majority of people, get a mild illness, to build up some degree of Herd Immunity as well so that more people are immune to this disease"
Patrick Valance, Government Chief Scientific Adviser, Today Programme, Radio 4, 13 March 8:10 a.m.
Patrick Valance, Government Chief Scientific Adviser, Today Programme, Radio 4, 13 March 8:10 a.m.
Adjust the parameters above and restart the simulation to see what percentage of the population must become infected to create herd immunity and protect against a secondary wave of infection.
Key
Uninfected: 
Infected:
Immune / Non infectious:
Hospitalisation & Death:
Final death toll calculated using UK population size & current UK infection death rates.
Infected:
Immune / Non infectious:
Hospitalisation & Death:
Final death toll calculated using UK population size & current UK infection death rates.
In this simulation no one is tested for an infection and no one is contact traced. The secondary wave of infections is imported from airport arrivals, who are not tested on entry.
In the default settings the primary infection is largely suppressed by the low mobility of the population. During the secondary infection mobility has returned to normal.
Notes on Data Sources
This simulation / zero player game is a response to statements by the UK Government and its scientific advisers during March and April 2020, in the first months of the COVID-19 Pandemic. Like most zero player pixel simulations it owes a debt to John Conway's 1970 Game of Life simulation. Conway died from COVID-19 on April 11, 2020.Herd Immunity
The term “herd immunity” has been used in relationship to COVID-19 to describe a situation where a particular proportion of individuals are immune and do not transmit the virus, leading to a decline in incidence of infection.Where there is no vaccine individual immunity is achieved by becoming infected, recovering and developing antibody immunity.
The proportion of individuals that need to be infected to reach herd immunity varies from virus to virus, depending on how infectious it is.
Patrick Valance, Government Chief Scientific Adviser, suggested that the proportion of the population that would need to be infected with COVID-19 to reach herd immunity was around sixty percent, whereas Graham Medley suggests 'most people' will have to have been infected.
Today Programme (2020), BBC Radio 4, (interview with Patrick Valance) 13 March. 8:10 a.m. Clip Available from:
https://twitter.com/BBCr4today/status/1238390547783528448?s=20
Parker, G., Pickard, J. & Hughes, L. (2020) UK’s chief scientific adviser defends ‘herd immunity’ strategy for coronavirus. Available from:
https://www.ft.com/content/38a81588-6508-11ea-b3f3-fe4680ea68b5
BBC Newsnight (2020), Coronavirus: Can herd immunity protect the population (interview with Graham Medley), BBC, 12 March. Available from:
https://youtu.be/blkDulsgh3Q
Fine, P., Eames, K. & Heymann, D. (2011) "Herd Immunity": A Rough Guide. Clinical Infectious Diseases. 52 (7), pp. 911-916. Available from:
https://academic.oup.com/cid/article/52/7/911/299077
Zandonella, C. (2020) Mathematician John Horton Conway, a ‘magical genius’ known for inventing the ‘Game of Life,’ dies at age 82. Available from:
https://www.princeton.edu/news/2020/04/14/mathematician-john-horton-conway-magical-genius-known-inventing-game-life-dies-age
Hospitalisation and Death Rates
The hospitalisation and death rate varies on each run of the simulation, but is based on UK data showing between 23% - 30% of those infected have been hospitalised during the pandemic.For example:
Downing Street data shows that there had been 16,563 hospital admissions and 6,200 deaths with COVID-19 by April 7 across the UK and the official Gov figures showed 55,200 people had tested positive for the virus by the same date. An admission rate of 30% and death rate of 11.2% of those infected.
Just a few days later on April 12th the official Gov figures showed 84,279 people had tested positive for COVID-19 and a total of 19,945 had now been admitted to hospital and 10,612 had died. An admission rate of 23% and a death rate of 12.6% of those infected.
This simulation uses these statistics to calculate the number of deaths.
However it is clear that currently this data does not relect the true scale of infection in the UK. Since it excludes anyone with COVID-19 who is not tested and hospitalised, which most likely includes all mild cases. Once these (unknown) number of infections are added to the total the death rate would likely be much lower than is currently reflected in Govenment / Public Heath England data.
UK Prime Minister. (2020) People in hospital beds with COVID-19 (Great Britain). Twitter. 9 April. Available from:
https://twitter.com/10DowningStreet/status/1248293570353692672?s=20
UK Government (2020) Number of coronavirus (COVID-19) cases and risk in the UK. Available from:
https://www.gov.uk/guidance/coronavirus-covid-19-information-for-the-public#number-of-cases-and-deaths
Otte, J., Murray, J., Adams, R., Siddique, H., Gayle, D. & Bowcott, O. (2020) UK coronavirus live: Matt Hancock announces contact tracing app as UK death toll passes 10,000. Guardian. 12 April. Available from:
https://www.theguardian.com/uk-news/live/2020/apr/12/coronavirus-live-news-nhs-staff-deaths-boris-johnson-latest-updates?page=with:block-5e932dde8f082dfd549d5148#block-5e932dde8f082dfd549d5148