Vaccine 22 (2004) 3546–3562 An economic evaluation of varicella vaccination in Italian adolescents Nancy Thiry a,∗ , Philippe Beutels a,b , Francesco Tancredi c , Luisa Romanò d , Alessandro Zanetti d , Paolo Bonanni e , Giovanni Gabutti f , Pierre Van Damme a a Centre for the Evaluation of Vaccination, Epidemiology and Social Medicine, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium b National Centre for Immunisation Research & Surveillance (NCIRS), University of Sydney & The Children’s Hospital at Westmead, and Centre for Health Economics Research and Evaluation (CHERE), University of Technology at Sydney (UTS), Sydney, NSW, Australia c Direzione Sanitaria, ASL NA/4, Via Nazionale delle Puglie, 80038 Pomigliano d’Arco, Naples, Italy d Institute of Virology, University of Milan, Via C. Pascal 38, 20133 Milan, Italy e Chair of Hygiene and Epidemiology, Public Health Department, University of Florence, Viale Morgagni 48, 50134 Florence, Italy f Lab of Hygiene, Department of Biological and Environmental Sciences and Technologies, University of Lecce, Via Provinciale Lecce-Monteroni, 73100 Lecce, Italy Received 18 December 2003; received in revised form 8 March 2004; accepted 29 March 2004 Available online 22 April 2004 Abstract An economic evaluation was performed to assess five varicella vaccination scenarios targeted to 11-year-old Italian adolescents. The scenarios were: “compulsory vaccination” of all adolescents, recommended vaccination of susceptible adolescents on the basis of an “anamnestic screening”, a “blood test” or a combination of both (“both tests”) and vaccination of adolescents in the private sector, at the parents’ charge (“private vaccination”). Probabilities and unit costs were taken from published sources and experts opinion. The accuracy of the anamnestic screening (81.6% sensitivity and 87.3% specificity) was derived from a separate descriptive study among 344 Italian adolescents. The costs and benefits of each scenario were simulated using a Markov model and cost-effectiveness, budget-impact and cost-benefit analyses were conducted. Of all considered scenarios, “both tests” and “anamnestic screening” were the most appealing options with an estimated net direct cost of 5058 and 8929 per life-year gained (compared to no vaccination) versus 14,693–42,842 for the other scenarios. These two scenarios further resulted in substantial net savings for society (over 600,000 per cohort, BCR: 2.17). The need for a serological confirmation was highly dependent on the sensitivity of the anamnestic screening, which is believed to increase once such a program is launched. For practical considerations, “anamnestic screening” seems to be the most convenient option. © 2004 Elsevier Ltd. All rights reserved. Keywords: Chickenpox; Adolescents; Cost-effectiveness; Varicella history; Modeling 1. Introduction Chickenpox (or varicella) is a common childhood disease resulting from a primary infection with the varicella-zoster virus (VZV). After experiencing varicella, the VZV becomes latent and may reactivate years to decades later causing her- pes zoster (or shingles). [1] Varicella is generally perceived as a mild disease given the high incidence of the infection in healthy children and its usually harmless outcome. How- ever, in rare occasions complications (mainly bacterial in- fection, pneumonia, cerebellar ataxia and encephalitis) and mortality may occur. Hospitalisation rates among individu- als aged 0–16 years are estimated to vary between 9 and 55 ∗ Corresponding author. Tel.: +32-0-3-820-26-58; fax: +32-0-3-820-26-40. E-mail address: nancy.thiry@ua.ac.be (N. Thiry). per 10,000 chickenpox cases, [2,3] and overall case-fatality rates between 1.2 [4] and 2.6 [5,6] per 100,000 cases. In adults, neonates and in immunocompromised children there is also evidence of a more severe disease. Moreover, the chance of complicated and fatal varicella increases with age at infection. [2,3,6,7] A varicella vaccine is available and its efficacy and safety are well documented. [8,9,10,11,12] In the US, the OKA/Merck vaccine is routinely administered to healthy children since 1995 and results of a population-based surveillance study in three counties have demonstrated a substantial decrease in varicella morbidity 6 years after the introduction of the vaccine. [13] Whether a similar universal varicella vaccination campaign should be imple- mented is still under debate in many other countries as the implications for public health are complex. Indeed, vacci- nation shifts, on average, the infection to older ages and 0264-410X/$ – see front matter © 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.vaccine.2004.03.043