Estimating the Health and Economic Impact of Universal Varicella Vaccination in Jordan

BACKGROUND: To evaluate the impact of adding universal varicella vaccination (UVV) to the existing childhood vaccination programme in Jordan, and identify the most cost-effective strategy. METHODS: A dynamic transmission model of varicella infection was calibrated to available varicella seroprevalence data within the region and validated against local epidemiological data. Local direct and indirect costs and healthcare utilization data were used. We considered the health and economic impact of one dose UVV administered concurrently with MMR at 12 months of age with 95% coverage, and two dose strategies with short (6 month) and long (4 year) intervals between First and Second dose. We took the societal perspective (direct and indirect costs) and discounted costs and QALYs by 3%/year to assess cost-effectiveness. RESULTS: The model estimated the current burden of varicella at 172,000 cases/year, an incidence rate of 2,200/100,000 persons. In the 5(th)/25(th) year after vaccination, all strategies substantially reduced total varicella incidence by 89.5%/96.6% (1 dose), 92.3%/98.0% (2 dose short), and 90.5%/98.3% (2 dose long), compared with no vaccine (Figure 1). In the absence of vaccination, an estimated $47.89 M ($28.81 M direct, $19.08 indirect) was spent annually on varicella treatment. The average annual total treatment costs over 25 years from the societal perspective were $4.01M (1 dose), $3.34M (2 dose short), and $3.43M (2 dose long). Considering a willingness to pay (WTP) threshold of $3,600 USD / QALY and the societal perspective, the 1 dose program was the most cost-effective with cost savings of $83.40 USD and health gain of 4.127 × 10(−5) QALYs per person. 2 dose programs are similarly cost-saving and highly effective, compared with a scenario of no vaccination; however, moving incrementally from a 1 dose strategy, incremental cost-effectiveness ratios (ICERS) were $6.9M/QALY (short vs. 1 dose) and $13.5M/QALY (long vs. short), both well as above the WTP threshold. All strategies reached. CONCLUSION: One or two dose UVV in Jordan will significantly reduce varicella disease burden and is cost saving relative to no vaccine over 25 years. DISCLOSURES: W. Hayajneh, Merck & Co., Inc.: Consultant, Consulting fee. J. Maalouf, Merck & Co., Inc.: Employee, Salary. B. Kuter, Merck & Co., Inc.: Employee, Salary.T. Weiss, Merck & Co., Inc.: Employee, Salary. V. Daniels, Merck & Co., Inc.: Employee, Salary. L. Wolfson, Merck & Co., Inc.: Employee, Salary.