The cost-effectiveness of varicella vaccine programs for Australia

Objective: to examine the cost-effectiveness of three different varicella V accination programs compared with no vaccination program. Design: cost-effectiveness study. Simulations of the costs and consequences of chickenpox and the vaccination programs over a 30-year period. Direct ( health-care) costs only were used in the simulations. Setting: Australia. Participants/subjects: annual birth cohorts of infants (12-months old) and adolescents (12 years old). Interventions: strategy I (no vaccination) was compared with three differen t varicella vaccination programs: strategy II - all infants; strategy III - adolescents without a history of varicella; and strategy IV ('catch-up') - all infants plus, for the first 11 years, adolescents without a history. Outcome measures: fatalities and hospitalisations for varicella and its com plications (encephalitis, pneumonitis, long-term disability). Results: the average cost per case of chickenpox averted was $64, $530 and $418 in the infant, adolescent and catch-up programs, respectively. The inf ant program was the most cost-effective of the three. This program could av ert 4.4 million cases, 13,500 hospitalisations and 30 fatalities for chicke npox over a 30-year period. Results were sensitive to the price of the vacc ine and the discount rate, but relatively insensitive to changes in vaccine efficacy, coverage rates or vaccine complication rates. Improved accuracy of a negative varicella history in adolescents would substantially reduce t he costs of the adolescent and catch-up programs making these programs feas ible. Conclusions: the infant vaccine program is the preferred program, but the d irect costs of any of the vaccination programs considered here are greater than the direct costs of no vaccination program. (C) 1999 Elsevier Science Ltd. All rights reserved.