OBJECTIVES

Cost savings associated with high-dose (HD) as compared to standard-dose (SD) influenza vaccination in the United States (US) Veteran’s Health Administration (VHA) population has been reported to be due to the additional prevention of hospitalizations for cardio-respiratory disease; however, the stratification of this outcome into cardiovascular and respiratory disease remains to be explored.

METHODS

Leveraging a relative vaccine effectiveness study of HD versus SD over five influenza seasons (2010/11 through 2014/15) in the VHA, we collected cost data for healthcare provided to these subjects at VHA as well as through Medicare services. Our economic assessment compared the costs of vaccination and hospital care for patients with cardiovascular and respiratory disease separately and combined. We calculated the instrumental variable (IV) adjusted relative vaccine effectiveness (rVE) for each of the outcomes to estimate the net savings adjusted for measured and unmeasured confounding factors.

RESULTS

We analyzed 3.5 million SD and 158,636 HD person-seasons. The average cost of HD and SD vaccination were $23.48 (95% CI: $21.29 - $25.85) and $12.21 (95% CI: $11.49 - $13.00) per recipient, respectively. The IV adjusted rVEs were 14% (95% CI: 7% - 20%) for cardiovascular; 15% (95% CI: 5% - 25%) for respiratory; and 14% (8% - 19%) for cardio-respiratory hospitalizations. Net cost-savings per HD vaccinated Veteran were $138 (95% CI: $66 - $200) for cardiovascular; $62 (95% CI: $10 - $107) for respiratory; and $202 (95% CI: $115 - $280) for cardio-respiratory hospitalizations.

CONCLUSIONS

For the five-season period of 2010/11 through 2014/15, the estimated reduction of hospitalizations for cardiovascular disease contributed substantially more than those for respiratory disease to the association between HD vaccination and net-cost savings for cardio-respiratory disease as compared to SD vaccination in the US VHA population.

This study was funded by Sanofi Pasteur.