Optimality of vaccination for an SIR epidemic with an ICU constraint

Fuente: arXiv
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Autori principali: Della Rossa, Matteo, Freddi, Lorenzo, Goreac, Dan
Natura: Preprint
Pubblicazione: 2024
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author Della Rossa, Matteo
Freddi, Lorenzo
Goreac, Dan
author_facet Della Rossa, Matteo
Freddi, Lorenzo
Goreac, Dan
contents This paper studies an optimal control problem for a class of SIR epidemic models, in scenarios in which the infected population is constrained to be lower than a critical threshold imposed by the ICU (intensive care unit) capacity. The vaccination effort possibly imposed by the health-care deciders is classically modeled by a control input affecting the epidemic dynamic. After a preliminary viability analysis the existence of optimal controls is established, and their structure is characterized by using a state-constrained version of Pontryagin's theorem. The resulting optimal controls necessarily have a bang-bang regime with at most one switch. More precisely, the optimal strategies impose the maximum-allowed vaccination effort in an initial period of time, which can cease only once the ICU constraint can be satisfied without further vaccination. The switching times are characterized in order to identify conditions under which vaccination should be implemented or halted. The uniqueness of the optimal control is also discussed. Numerical examples illustrate our theoretical results and the corresponding optimal strategies. The analysis is eventually extended to the infinite horizon by $Γ$-convergence arguments.
format Preprint
id arxiv_https___arxiv_org_abs_2407_08425
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Optimality of vaccination for an SIR epidemic with an ICU constraint
Della Rossa, Matteo
Freddi, Lorenzo
Goreac, Dan
Optimization and Control
This paper studies an optimal control problem for a class of SIR epidemic models, in scenarios in which the infected population is constrained to be lower than a critical threshold imposed by the ICU (intensive care unit) capacity. The vaccination effort possibly imposed by the health-care deciders is classically modeled by a control input affecting the epidemic dynamic. After a preliminary viability analysis the existence of optimal controls is established, and their structure is characterized by using a state-constrained version of Pontryagin's theorem. The resulting optimal controls necessarily have a bang-bang regime with at most one switch. More precisely, the optimal strategies impose the maximum-allowed vaccination effort in an initial period of time, which can cease only once the ICU constraint can be satisfied without further vaccination. The switching times are characterized in order to identify conditions under which vaccination should be implemented or halted. The uniqueness of the optimal control is also discussed. Numerical examples illustrate our theoretical results and the corresponding optimal strategies. The analysis is eventually extended to the infinite horizon by $Γ$-convergence arguments.
title Optimality of vaccination for an SIR epidemic with an ICU constraint
topic Optimization and Control
url https://arxiv.org/abs/2407.08425