Mumps in the US Army 1980-86: Should recruits be immunized?

The US Army's experience with mumps hospitalizations was examined for the years 1980 through 1986. One hundred fifty-two cases among active duty Army soldiers were identified. Mumps rates declined from 3.85 per 100,000 active duty soldiers per year in 1980 to 1.28 in 1985, but an outbreak during 1986 caused rates to jump to 6.65. Attack rates were found to decline dramatically with increasing age or length of military service, with 74 per cent of cases occurring in soldiers with three years or less of service. Rates for Blacks and Whites were similar, but were higher for other minorities. Complications reported were mild. A cost-benefit analysis, assuming all recruits were to be vaccinated, estimated average annual vaccination program costs of $286,789; this figure exceeds average annual reported hospitalized mumps disease costs of $61,525 by a factor of 4.7. Mumps attack rates would have to reach at least 15.0 per 100,000 per year before savings would equal recruit vaccination costs. Failure to show that a vaccine program would be cost-saving may be due to limitations in identifying cases or to the requirement that all recruits be immunized regardless of prior immune status. It is likely that a program to immunize susceptible individuals alone would show benefit.