Comparative study of reactions and serological response to cholera vaccines in a controlled field trial conducted in the USSR

This article presents the results of a comparative study of the reactogenicity and the serological response induced by a number of cholera vaccines. Conducted in the USSR on 998 adults aged 18 years and over, the study covered whole-cell heat-killed and formalin-inactivated cholera vaccines, whole-cell heat-killed El Tor vaccine, and a new partially purified toxoid preparation proposed for the immunoprophylaxis of cholera-all administered by hypodermic syringe or jet injector. The most marked reactions were found to occur with the formalin-inactivated cholera vaccine and the least marked with the partially purified toxoid. It was also established that the toxoid was no less effective than the whole-cell vaccine in inducing the intense production of antibodies to the Inaba serotype and, in somewhat lesser degree, to the Ogawa serotype of the El Tor vibrio. It was the only preparation to give rise to intense production of specific antitoxins in 95-98% of cases. The reactions to and immunogenic properties of the cholera vaccines did not show any statistically significant difference whether administered by hypodermic syringe or by jet injector.