An incremental economic evaluation of targeted and universal influenza vaccination in pregnant women

Objective: Pregnancy is associated with increased influenza hospitalizations and physician visits (events) in healthy women and those with co-morbidities. Annual influenza immunization is recommended for all pregnant women. Although vaccination is expected to reduce influenza-related events, the economic implications are unclear. We developed an economic model to estimate the cost-effectiveness (CE) of different vaccination strategies in Nova Scotia. Methods: A decision tree characterized the one-year costs and consequences of targeted (pregnant women with co-morbidities only) and universal (all pregnant women) vaccination strategies relative to a no-vaccination strategy. Baseline event probabilities, vaccine effectiveness, costs and quality-of-life weights were derived from individual-level Nova Scotia administrative databases, health system sources and published reports. Sensitivity analyses tested the impact of varying key parameters, including vaccine effectiveness and mode of delivery. Results: Targeted vaccination was cost-saving relative to no vaccination when delivered by public health clinics (PHC) or routine family practitioner (FP) visit. Cost per quality-adjusted life year gained by universal vaccination relative to targeted strategy was <$40,000 when delivered by PHC or routine FP visit. Net cost of universal vaccination by PHC or a routine FP visit was <$10 per pregnant woman. Conclusion: Universal vaccination of pregnant women appears cost-effective when delivered by PHC or as part of a routine FP prenatal visit. Targeted vaccination of pregnant women with co-morbidities can be cost-saving, but the possibility of higher vaccine uptake with a universal compared to a targeted strategy must be considered in addition to costs in program planning.