Comparable Cost-Effectiveness with LAIV versus IIV Found in Young Children

Despite findings from a recent randomized controlled trial among young children that intranasal live attenuated influenza vaccine (LAIV) might cause an increase in adverse events (AEs) compared with the inactivated influenza vaccine (IIV), new research found that the cost-effectiveness of the 2 approaches remains comparable. The results of the study were published in the Archives of Pediatrics & Adolescent Medicine [2011;165(2):112-118]. Given that a possible increase in AEs was of potential concern to healthcare providers and parents, Lisa A. Prosser, PhD, from the University of Michigan, and her colleagues, evaluated the effect of AEs associated with LAIV in children <5 years of age on the cost-effectiveness of influenza vaccination. The researchers developed a decision-analytic model to predict costs and health effects of no vaccination, vaccination with LAIV, and vaccination with IIV in hypothetical cohorts of healthy children aged 6 months to 4 years. The analysis included the potential increased incidence of AEs following vaccination with LAIV for children <5 years, including fever, wheezing, and hospitalization. Healthy children were divided into subgroups by age: 6 to 23 months, 2 years, and 3 to 4 years. A time frame of 1 year was used but also included the long-term effects of influenza and influenza vaccines. The investigators previously reported that the same mathematical simulation model showed comparable cost-effectiveness between the 2 vaccine approaches in 2006. This analysis incorporated newly identified potential AEs for LAIV, revised assumptions regarding the relative incidence of previously identified AEs for LAIV and IIV, and new data on the costs of influenza-related hospitalizations. The primary outcome measure was the incremental cost-effectiveness ratio in dollars per quality-adjusted life-year (QALY) saved for vaccination, compared with no vaccination. The model showed that the cost-effectiveness ratios ranged from $20,000/QALY (age 6-23 months) to $33,000/QALY (age 3-4 years) for LAIV. Similarly, the cost-effectiveness ratio ranged from $21,000/QALY to $37,000/QALY with IIV, respectively. The addition of wheezing-related AEs had little impact on the cost-effectiveness of vaccination with LAIV. Even after inclusion of wheezing-related AEs, vaccination with LAIV resulted in health benefits that outweighed AEs as measured by QALYs, the researchers said. In this low-risk hypothetical cohort of children aged 6 months to 4 years, LAIV was projected to avert more episodes of influenza, influenza-related hospitalizations, and death than IIV per 1000 children vaccinated. Yet, AEs were projected to be higher for LAIV. However, either vaccine strategy showed a net benefit, compared with no vaccination, as measured by QALYs gained. QALYs gained with LAIV were 3.6 (95% confidence interval [CI], 0.4-10.2 for children age 6-23 months), 2.9 (95% CI, 0.3-8.3 for children 2 years of age), and 2.0 (95% CI, 0.2-6.0 for children 3-4 years of age). For QALYs gained with IIV in the same subgroups, the results were 3.0 (95% CI, 0.4-8.7), 2.4 (95% CI, 0.3-7.2), and 1.7 (95% CI, 0.2-5.1), respectively. One potential limitation in this study is the exclusion of herd immunity effects. “If these effects were considered, they would likely result in more favorable cost-effectiveness ratios for vaccination options,” the investigators noted. Furthermore, published data were not available for some key variables, such as quality adjustment for a wheezing episode and hospitalizations following vaccination. This study used values from similar health states not associated with vaccination. The researchers summarized that the cost-effectiveness of LAIV for children remains favorable when factoring in new data for vaccine-related AEs. Additionally, cost-effectiveness ratios were comparable for LAIV and IIV for low-risk children aged 6 months to 4 years. They recommended that post-licensing safety studies of both treatment approaches in children continue to track wheezing-related AEs, including all-cause hospitalization.