Rickettsial vaccines: the old and the new.

In the past century vaccine development for prevention of rickettsial diseases has been prolific. However, in the past 20 years no new rickettsial vaccine has been manufactured and there are currently no new or old rickettsial vaccines licensed. Early rickettsial vaccines were difficult, expensive and very hazardous to produce. Molecular biology techniques of today are currently being used to develop new rickettsial vaccines that are standardized, inexpensive, nonhazardous and efficacious.