Rocky Mountain Spotted Fever: Results of Fifteen Years' Prophylactic Vaccination

Abstract

The Public Health Service vaccine for the prevention of Rocky Mountain spotted fever is made from virus-laden tissues of infected adults of the Rocky Mountain wood tick, Dermacentor andersoni. The evidence of the protective value of this vaccine is embodied in 3 groups of data covering its use in the Rocky Mountain region and adjacent areas, i.e., throughout the range of its western vector, D. andersoni. The first and by far the most significant set of data concern 15 years' use in the much publicized western Montana area of highly fatal infections; the second, the results of a 2-year test made in 1926 and 1927 in a highly exposed occupational group in a southern Idaho area where the casefatality rate was low; while the third consists of somewhat less significant evidence from 13 years' use in sections of the West other than the western Montana area. 1