Herpes zoster arises from reactivation of the varicella–zoster virus (VZV), causing varicella in children. As reactivation occurs when cell-mediated immunity (CMI) declines, and there is evidence that re-exposure to VZV boosts CMI, mass varicella immunization might increase the zoster burden, at least for some decades. Fear of this natural zoster boom is the main reason for the paralysis of varicella immunization in Europe. We apply optimal control to a realistically parametrized age-structured model for VZV transmission and reactivation to investigate whether feasible varicella immunization paths that are optimal in controlling both varicella and zoster exist. We analyse the optimality system numerically focusing on the role of the cost functional, of the relative zoster–varicella cost and of the planning horizon length. We show that optimal programmes will mostly be unfeasible for public health owing to their complex temporal profiles. This complexity is the consequence of the intrinsically antagonistic nature of varicella immunization programmes when aiming to control both varicella and zoster. However, we show that gradually increasing—hence feasible—vaccination schedules can perform better than routine programmes with constant vaccine uptake. Finally,we showthe optimal profiles of feasible programmes targeting mitigation of the post-immunization natural zoster boom with priority.

Perspectives on optimal control of varicella and herpes zoster by mass routine varicella vaccination

LANDI, ALBERTO;MANFREDI, PIETRO ANGELO MANFREDO FRANCESCO
2016-01-01

Abstract

Herpes zoster arises from reactivation of the varicella–zoster virus (VZV), causing varicella in children. As reactivation occurs when cell-mediated immunity (CMI) declines, and there is evidence that re-exposure to VZV boosts CMI, mass varicella immunization might increase the zoster burden, at least for some decades. Fear of this natural zoster boom is the main reason for the paralysis of varicella immunization in Europe. We apply optimal control to a realistically parametrized age-structured model for VZV transmission and reactivation to investigate whether feasible varicella immunization paths that are optimal in controlling both varicella and zoster exist. We analyse the optimality system numerically focusing on the role of the cost functional, of the relative zoster–varicella cost and of the planning horizon length. We show that optimal programmes will mostly be unfeasible for public health owing to their complex temporal profiles. This complexity is the consequence of the intrinsically antagonistic nature of varicella immunization programmes when aiming to control both varicella and zoster. However, we show that gradually increasing—hence feasible—vaccination schedules can perform better than routine programmes with constant vaccine uptake. Finally,we showthe optimal profiles of feasible programmes targeting mitigation of the post-immunization natural zoster boom with priority.
2016
Betta, Monica; Laurino, Marco; Pugliese, Andrea; Guzzetta, Giorgio; Landi, Alberto; Manfredi, PIETRO ANGELO MANFREDO FRANCESCO
File in questo prodotto:
File Dimensione Formato  
Betta_et_al_ProceedingsB_2016.pdf

solo utenti autorizzati

Descrizione: Main text
Tipologia: Versione finale editoriale
Licenza: NON PUBBLICO - Accesso privato/ristretto
Dimensione 980.91 kB
Formato Adobe PDF
980.91 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
Draft Perspectives on optimal control.pdf

accesso aperto

Tipologia: Documento in Post-print
Licenza: Creative commons
Dimensione 460.61 kB
Formato Adobe PDF
460.61 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/827758
Citazioni
  • ???jsp.display-item.citation.pmc??? 5
  • Scopus 15
  • ???jsp.display-item.citation.isi??? 13
social impact