Economic value of seasonal and pandemic influenza vaccination during pregnancy

Abstract

Background: The cost-effectiveness of maternal influenza immunization against laboratory-confirmed influenza has never been studied. The current 2009 H1N1 influenza pandemic provides a timely opportunity to perform such analyses. The study objective was to evaluate the cost-effectiveness of maternal influenza vaccination using both single- and 2-dose strategies against laboratory-confirmed influenza secondary to both seasonal epidemics and pandemic influenza outbreaks.

Methods: A cost-effectiveness decision analytic model construct using epidemic and pandemic influenza characteristics from both the societal and third-party payor perspectives. A comparison was made between vaccinating all pregnant women in the United States versus not vaccinating pregnant women. Probabilistic (Monte Carlo) sensitivity analyses were also performed. The main outcome measures were incremental cost-effectiveness ratios (ICERs).

Results: Maternal influenza vaccination using either the single- or 2-dose strategy is a cost-effective approach when influenza prevalence > or =7.5% and influenza-attributable mortality is > or =1.05% (consistent with epidemic strains). As the prevalence of influenza and/or the severity of the outbreak increases the incremental value of vaccination also increases. At a higher prevalence of influenza (> or =30%) the single-dose strategy demonstrates cost-savings while the 2-dose strategy remains highly cost-effective (ICER, < or =$6787.77 per quality-adjusted life year).

Conclusions: Maternal influenza immunization is a highly cost-effective intervention at disease rates and severity that correspond to both seasonal influenza epidemics and occasional pandemics. These findings justify ongoing efforts to optimize influenza vaccination during pregnancy from an economic perspective.

Figure 1

A General model structure B Maternal and neonatal influenza subtrees.

Figure 2

Incremental cost - effectiveness ratio (ICERs) for vaccinating pregnant women for influenza at different vaccine efficacies and influenza prevalence (single vaccine dose). Probabilities of mortality were 1.05%, 2.10%, and 4.20% for panels A–C, respectively. *12.5% is the most likely value from the Centers for Disease Control and Prevention annual influenza prevalence estimate. QALY, quality - adjusted life year.

Figure 3

Acceptability curves at different influenza prevalence levels for base case vaccine efficacy and influenza - attributable mortality from a societal perspective (single vaccine dose). *12.5% is the most likely value from the Centers for Disease Control and Prevention annual influenza prevalence estimate. Base case vaccine efficacy, 73% for mothers and 63% for neonates; base case influenza - attributable mortality, 1.05%.