Influence of timing of seasonal influenza vaccination on effectiveness and cost-effectiveness in pregnancy.

The purpose of this review was to estimate the impact of timing of seasonal influenza vaccination during pregnancy on health and economic outcomes. Cost-effectiveness analysis with a dynamic model of the US population of pregnant women and infants who were <6 months incorporated seasonal variation in influenza incidence. Compared with no vaccination, seasonal influenza vaccination in pregnancy costs $70,089 per quality-adjusted life year. Most of the benefit for infants was limited to those whose mothers were vaccinated within the first 4 weeks of vaccine availability. Once all women who were pregnant at the time of vaccine availability were vaccinated, vaccination of newly pregnant women had benefits for mothers but not infants. Delay of vaccination beyond November reduced both effectiveness and cost-effectiveness. The greatest population benefit from seasonal influenza vaccination in pregnancy was realized if pregnant women were vaccinated as soon as possible after trivalent inactivated influenza vaccine became available. Efforts to increase vaccine rates should be concentrated early in the influenza season.