Estimating the Long-Term Clinical and Economic Impact of Universal Varicella Vaccination in Portugal Using a Dynamic...

Varicella vaccination is not currently included in Portugal's childhood national immunization program. We modeled the clinical and economic impact of a two-dose universal varicella vaccination (UVV) program in Portugal.

A dynamic transmission model was adapted to Portugal to assess the impact of UVV over a 50-year time horizon. Two two-dose UVV strategies (first dose at 12 months, second dose at 5 years) were compared to no vaccination. Clinical outcomes included varicella and herpes zoster incidence rates, cases, deaths, quality-adjusted life years (QALYs) lost, and varicella-related health care resource use. Costs were assessed from the payer perspective (direct costs of treatment) and societal perspective (direct costs plus indirect costs of lost workdays).

Both UVV strategies reduced total varicella cases by 79.4-85.3%, outpatient visits by 78.9-84.8%, and varicella hospitalizations by 69.3-71.3% compared to no varicella vaccination. Herpes zoster cases were reduced by 2.4-2.9%. These strategies resulted in the gain of 5977-6094 QALYs and cost savings of €12.0 million (M)-15.9M from the payer perspective and €84.2M-93.9M from the societal perspective.

A two-dose UVV program is estimated to substantially reduce the burden of varicella disease in Portugal and to be cost-saving from both the payer and societal perspectives.