Published October 18, 2026 | Version v6

Epidemic modelling for children

Authors/Creators

  • 1. StochAnswers

Description

It is argued that the fundamental science of an epidemic is that of one of the standard stochastic processes, one that should be familiar to anyone who has ever shuffled and dealt a pack of cards. An epidemic is modelled as a game of tag with two rules. A game of tag is modelled as a game of cards with two packs. For this minimal SIR model the act of tagging is seen to be selection without replacement. Averaging the associated probability distribution results in the logistic growth term of the standard SIR model with a slight correction to be consistent with the definition of the basic reproduction number. Being an agent-based model it is easily extended from the complete graph to social networks leading to a flattening of the curve with far fewer individuals having acquired immunity by the end of the epidemic. Textbook examples of a number of competing epidemic models which use different stochastic processes are listed for comparison. The Mathematical arguments contained in this paper are accessible from primary school to undergraduate levels. The decreasing probability of the game matching exponential growth can be calculated in a manner similar to the solution of the Birthday problem. There are also difference equations and differential equations making this theory a rich and varied example for teachers whose pupils may be interested after events of recent years.

Files

minimal.pdf

Files (132.9 kB)

Name Size
md5:63761279c6065298a86091d4e9953d0f
132.9 kB Preview Download

Additional details

Software

Repository URL
https://stochanswers.com/education/tag.html
Programming language
JavaScript
Development Status
Active

References

  • K. Muroi, The oldest example of compound interest in sumer: Seventh power of four-thirds (2015). arXiv:1510.00330. URL https://arxiv.org/abs/1510.00330
  • T. R. Malthus, An Essay on the Principle of Population, as it Affects the Future Improvement of Society. With Remarks on the Speculations of Mr. Godwin, M. Condorcet, and Other Writers, J. Johnson, London, 1798, published anonymously
  • W. Farr, Causes of death in england and wales, Report Appendix to the Second Annual Report, Registrar General of Births, Deaths, and Marriages in England, London, published in the Second Annual Report of the Registrar General of Births, Deaths, and Marriages in England (1840)
  • C. R. Darwin, On the origin of species by means of natural selection, or, The preservation of favoured races in the struggle for life, John Murray, London, 1859
  • A. J. Lotka, Elements of Physical Biology, Williams & Wilkins, Baltimore, 1925
  • V. Volterra, Variazioni e fluttuazioni del numero d'individui in specie animali conviventi, Memorie della Reale Accademia Nazionale dei Lincei 2 (1926) 31–113
  • W. O. Kermack, A. G. McKendrick, Contributions to the mathematical theory of epidemics, part i, Proceedings of the Royal Society of Edinburgh. Section A. Mathematics 115 (1927) 700–721
  • W. H. Frost, Infection, immunity and disease in the epidemiology of diphtheria, with special reference to some studies in baltimore., Journal of Preventive Medicine 2(4) (1928) 325–343
  • R. A. Fisher, F. Yates, Statistical tables for biological, agricultural and medical research (3rd ed.), Oliver & Boyd., London, 1948.
  • S. Davis, B. Abbasi, S. Shah, M. Begon, Spatial analyses of wildlife contact networks., Journal of the Royal Society Interface 12(102). doi:10.1098/rsif.2014.1004.
  • R. A. Rossi, N. K. Ahmed, The network data repository with interactive graph analytics and visualization, in: AAAI, 2015. URL https://networkrepository.com
  • M. J. Keeling, P. Rohani, Modeling Infectious Diseases in Humans and Animals, Princeton University Press, 2008.
  • D. T. Gillespie, Exact stochastic simulation of coupled chemical reactions, The Journal of Physical Chemistry 81 (25) (1977) 2340–2361.