Prevention of adenoviral acute respiratory disease in Army recruits: cost-effectiveness of a military vaccination policy.

Since 1971 widespread vaccination has limited the number of adenoviral acute respiratory disease (ARD) outbreaks in Army recruits. Increased vaccine costs have recently threatened the continuation of the vaccination program. We conducted a cost-effectiveness analysis to assess the consequences of changing the year-round Army adenovirus vaccination program to (1) seasonally targeted vaccine administration (only during the high-risk period) or (2) complete discontinuation of the program from the perspective of total cost to the Army. Costs included vaccination costs and direct and indirect medical and military training costs. Health outcomes were estimated as the number of hospitalizations for ARD prevented. In the reference case, the incidence rate among unvaccinated and vaccinated individuals was 4.06 and 1.5 per 100 person weeks, respectively. Results are expressed for a cohort of 76,171 recruits. In the absence of adenoviral vaccination, a projected 12,370 cases of ARD hospitalization would occur, costing $26.4 million annually. A seasonally targeted program would prevent 7,800 cases of ARD and save $16.1 million over no vaccination. Year-round immunization would not prevent any additional cases but would save $15.5 million over no vaccination. Year-round vaccination would become the cost-effective strategy if ARD incidence during the low-risk months were to increase. Vaccination of Army recruits by any schedule was cost-saving due to the high level of prevented disease and averted hospitalizations. Even though a seasonally targeted program provided the greatest cost-savings, year-round vaccination must remain an option due to the potential for adenoviral ARD outbreaks in the low-risk period.