The continuing imperatives of diversity of rabies vaccine

Current preoccupation with and enthusiasm for the human diploid cell rabies vaccine are reminiscent of the advent of duck embryo vaccine (DEV) a quarter of a century ago. Development of the latter vaccine, considered both potent and entirely safe at the time, had the effect of paralyzing development of other vaccines, at least in the United States. Subsequent experience has demonstrated the DEV is neither potent nor entirely safe, although its use is not attended by the trepidation that accompanied the use of older vaccines. Availability in the USA of only one vaccine licensed for human use has created a hardship on both patients and physicians in as much as a large percentage of vaccinated persons suffer side effects of various degrees that pose problems for continuation of treatment. Experience has shown that most of those problems can be resolved by simple substitution of vaccine of another kind. Data obtained thus far indicate the marked superiority of diploid cell vaccine over DEV in several respects but it is not yet evident that it is completely free of allergen. Moreover, purified preparations of antigenic fractions have been obtained, and other vaccines have been shown to benefit, in apparent potency, from their capability of eliciting interferon formation. Economic considerations cannot be overlooked, and the advantage, in this respect, of suckling mouse brain vaccine in some areas of greatest need is evident.