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Cutoff for the logistic SIS epidemic model with self-infection

Published online by Cambridge University Press:  04 June 2025

Roxanne He*
Affiliation:
The University of Melbourne
Malwina Luczak*
Affiliation:
The University of Manchester
Nathan Ross*
Affiliation:
The University of Melbourne
*
*Postal address: School of Mathematics and Statistics, University of Melbourne, VIC, 3010, Australia
***Postal address: Department of Mathematics, The University of Manchester, Oxford Road, Manchester, M13 9PL,United Kingdom. Email: malwina.luczak@manchester.ac.uk
*Postal address: School of Mathematics and Statistics, University of Melbourne, VIC, 3010, Australia

Abstract

We study a variant of the classical Markovian logistic SIS epidemic model on a complete graph, which has the additional feature that healthy individuals can become infected without contacting an infected member of the population. This additional ‘self-infection’ is used to model situations where there is an unknown source of infection or an external disease reservoir, such as an animal carrier population. In contrast to the classical logistic SIS epidemic model, the version with self-infection has a non-degenerate stationary distribution, and we derive precise asymptotics for the time to converge to stationarity (mixing time) as the population size becomes large. It turns out that the chain exhibits the cutoff phenomenon, which is a sharp transition in time from one to zero of the total variation distance to stationarity. We obtain the exact leading constant for the cutoff time and show that the window size is of constant (optimal) order. While this result is interesting in its own right, an additional contribution of this work is that the proof illustrates a recently formalised methodology of Barbour, Brightwell and Luczak (2022), ‘Long-term concentration of measure and cut-off’, Stochastic Processes and their Applications 152, 378–423, which can be used to show cutoff via a combination of concentration-of-measure inequalities for the trajectory of the chain and coupling techniques.

Type
Original Article
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of Applied Probability Trust

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References

Achterberg, M. A., Prasse, B. and Van Mieghem, P. (2022). Analysis of continuous-time markovian $\varepsilon$ -sis epidemics on networks. Physical Review E 105, 054305.10.1103/PhysRevE.105.054305CrossRefGoogle ScholarPubMed
Aldous, D. and Diaconis, P. (1986). Shuffling cards and stopping times. The American Mathematical Monthly 93, 333348.10.1080/00029890.1986.11971821CrossRefGoogle Scholar
Ames, W. F. and Pachpatte, B. (1997). Inequalities for differential and integral equations vol. 197. Elsevier.Google Scholar
Andersson, H. and Djehiche, B. (1998). A threshold limit theorem for the stochastic logistic epidemic. Journal of Applied Probability 35, 662670.10.1239/jap/1032265214CrossRefGoogle Scholar
Barbour, A. D. (1976). Quasi–stationary distributions in markov population processes. Advances in Applied Probability 8, 296314.10.2307/1425906CrossRefGoogle Scholar
Barbour, A. D., Brightwell, G. and Luczak, M. (2022). Long-term concentration of measure and cut-off. Stochastic Processes and their Applications 152, 378423.10.1016/j.spa.2022.05.004CrossRefGoogle Scholar
Barbour, A. D. and Luczak, M. (2012). A law of large numbers approximation for markov population processes with countably many types. Probability Theory and Related Fields 153, 727757.10.1007/s00440-011-0359-2CrossRefGoogle Scholar
Basu, R., Hermon, J. and Peres, Y. (2014). Characterization of cutoff for reversible markov chains. In Proceedings of the twenty-sixth annual ACM-SIAM symposium on Discrete algorithms. SIAM. pp. 17741791.Google Scholar
Boyce, W. E., DiPrima, R. C., Villagómez Velázquez, H. et al. (2004). Elementary differential equations and boundary value problems. Ecuaciones diferenciales y problemas con valores en la frontera.Google Scholar
Brightwell, G., House, T. and Luczak, M. (2018). Extinction times in the subcritical stochastic sis logistic epidemic. Journal of Mathematical Biology 77, 455493.10.1007/s00285-018-1210-5CrossRefGoogle ScholarPubMed
Chen, G.-Y. and Saloff-Coste, L. (2013). On the mixing time and spectral gap for birth and death chains. ALEA Latin American Journal of Probability and Mathematical Statistics 10, 293321.Google Scholar
Chen, G.-Y. and Saloff-Coste, L. (2014). Spectral computations for birth and death chains. Stochastic Processes and Applications 124, 848882.10.1016/j.spa.2013.10.002CrossRefGoogle Scholar
Chen, G.-Y. and Saloff-Coste, L. (2015). Computing cutoff times of birth and death chains. Electronic Journal of Probability 20, no. 76, 47.10.1214/EJP.v20-4077CrossRefGoogle Scholar
Diaconis, P. and Shahshahani, M. (1981). Generating a random permutation with random transpositions. Zeitschrift für Wahrscheinlichkeitstheorie und verwandte Gebiete 57, 159179.10.1007/BF00535487CrossRefGoogle Scholar
Ding, J., Lubetzky, E. and Peres, Y. (2010). Total variation cutoff in birth-and-death chains. Probabability Theory and Related Fields 146, 6185.10.1007/s00440-008-0185-3CrossRefGoogle Scholar
Doering, C. R., Sargsyan, K. V. and Sander, L. M. (2005). Extinction times for birth-death processes: Exact results, continuum asymptotics, and the failure of the fokker–planck approximation. Multiscale Modeling & Simulation 3, 283299.10.1137/030602800CrossRefGoogle Scholar
Eskenazis, A. and Nestoridi, E. (2020). Cutoff for the bernoulli–laplace urn model with o(n) swaps. In Annales de l’Institut Henri Poincaré, Probabilités et Statistiques. vol. 56 Institut Henri Poincaré. pp. 26212639.10.1214/20-AIHP1052CrossRefGoogle Scholar
Feller, W. (1939). Die grundlagen der volterraschen theorie des kampfes ums dasein in wahrscheinlichkeitstheoretischer behandlung. Acta Biotheoretica 5, 1140.10.1007/BF01602932CrossRefGoogle Scholar
Foxall, E. (2021). Extinction time of the logistic process. Journal of Applied Probability 58, 637676.10.1017/jpr.2020.112CrossRefGoogle Scholar
Hill, A. L., Rand, D. G., Nowak, M. A. and Christakis, N. A. (2010). Infectious disease modeling of social contagion in networks. PLOS Computational Biology 6, 115.10.1371/journal.pcbi.1000968CrossRefGoogle ScholarPubMed
Keeling, M. J. and Ross, J. V. (2008). On methods for studying stochastic disease dynamics. Journal of the Royal Society Interface 5, 171181.10.1098/rsif.2007.1106CrossRefGoogle ScholarPubMed
Kurtz, T. G. (1971). Limit theorems for sequences of jump markov processes approximating ordinary differential processes. Journal of Applied Probability 8, 344356.10.2307/3211904CrossRefGoogle Scholar
Levin, D. A. and Peres, Y. (2017). Markov chains and mixing times vol. 107. American Mathematical Soc.10.1090/mbk/107CrossRefGoogle Scholar
Lopes, F. and Luczak, M. (2020). Extinction time for the weaker of two competing sis epidemics. The Annals of Applied Probability 30, 28802922.10.1214/20-AAP1576CrossRefGoogle Scholar
Nåsell, I. (1996). The quasi-stationary distribution of the closed endemic sis model. Advances in Applied Probability 28, 895932.10.2307/1428186CrossRefGoogle Scholar
Nåsell, I. (1999). On the quasi-stationary distribution of the stochastic logistic epidemic. Mathematical Biosciences 156, 2140.10.1016/S0025-5564(98)10059-7CrossRefGoogle ScholarPubMed
Nieddu, G. T., Forgoston, E. and Billings, L. (2022). Characterizing outbreak vulnerability in a stochastic sis model with an external disease reservoir. Journal of the Royal Society Interface 19, 20220253.10.1098/rsif.2022.0253CrossRefGoogle Scholar
Salez, J. (2024). Cutoff for non-negatively curved Markov chains. Journal of the European Mathematical Society 26, 43754392.10.4171/jems/1348CrossRefGoogle Scholar
Stone, P., Wilkinson-Herbots, H. and Isham, V. (2008). A stochastic model for head lice infections. Journal of Mathematical Biology 56, 743763.10.1007/s00285-007-0136-0CrossRefGoogle ScholarPubMed
Van Mieghem, P. (2020). Explosive phase transition in susceptible-infected-susceptible epidemics with arbitrary small but nonzero self-infection rate. Physical Review E 101, 032303.10.1103/PhysRevE.101.032303CrossRefGoogle ScholarPubMed
Van Mieghem, P. and Cator, E. (2012). Epidemics in networks with nodal self-infection and the epidemic threshold. Physical Review E 86, 016116.10.1103/PhysRevE.86.016116CrossRefGoogle ScholarPubMed
Van Mieghem, P. and Wang, F. (2020). Time dependence of susceptible-infected-susceptible epidemics on networks with nodal self-infections. Physical Review E 101, 052310.10.1103/PhysRevE.101.052310CrossRefGoogle ScholarPubMed
Weiss, G. H. and Dishon, M. (1971). On the asymptotic behavior of the stochastic and deterministic models of an epidemic. Mathematical Biosciences 11, 261265.10.1016/0025-5564(71)90087-3CrossRefGoogle Scholar