Published online by Cambridge University Press: 06 June 2012
A decision analytical model is presented and analysed to assess the effectiveness andcost-effectiveness of routine vaccination against varicella and herpes-zoster, orshingles. These diseases have as common aetiological agent the varicella-zoster virus(VZV). Zoster can more likely occur in aged people with declining cell-mediated immunity.The general concern is that universal varicella vaccination might lead to more cases ofzoster: with more vaccinated children exposure of the general population to varicellainfectives become smaller and thus a larger proportion of older people will have weakerimmunity to VZV, leading to more cases of reactivation of zoster. Our compartment modelshows that only two possible equilibria exist, one without varicella and the other onewhere varicella and zoster both thrive. Threshold quantities to distinguish these casesare derived. Cost estimates on a possible herd vaccination program are discussedindicating a possible tradeoff choice.