Vax-SPIRAL®: Cuban antileptospirosis vaccines for humans: Clinical and field assays and impact of the vaccine on the disease after 11 years of application in Cuba

Abstract

Background: In Cuba, leptospirosis has shown an endemoepidemic behavior, with an important increase in morbility between 1991 and 1995, that is why these years have been considered epidemic. According to what had been foreseen within the Leptospirosis Prevention and Control Program, a Russian vaccine was administered to persons at risk of getting the disease since 1983. In 1991, import of this vaccine was stopped and, in order to find an alternative solution to this health problem, it was decided to start the development of a trivalent Cuban vaccine with autochthonous strains (Icteroahemorrahgiae, Canicola, Pomona). The objective was to carry out the clinical evaluation and to observe the impact of the Cuban vaccine against human leptospirosis in persons exposed to the risk of getting this disease. Methods: The first studies conducted were controlled clinical assays to evaluate both reactogenicity and immunogenicity of the vaccine in different groups of volunteers. Nine hundred and fifty-eight volunteers participated in the studies. To evaluate the vaccine efficacy, a controlled, randomized, double blind clinical assay was performed in Villa Clara province with 101 832 volunteers, who were followed up for one year. Another studied was carried out in 101 137 persons at risk in Holguin province with the same objective: to evaluate the vaccine effectiveness. Results: The clinical evaluation showed safety and low reactogenicity. Immunogenicity was comparable to that of other bacterines. Efficacy was of 78.1% (IC 95%: 58.2 to 88.3) and the RR of getting sick of vaccinated individuals, with regard to non-vaccinated ones, was 0.22. So, a protective effect of the vaccine administration was considered. The vax-SPIRAL vaccine was registered in 1998 and included within the Leptospirosis Prevention and Control Program. Since the introduction of this vaccine, a marked decrease in leptospirosis cases has been observed. It has been possible to administered more than 8 million of doses and morbility has been diminished to 84.1%. Conclusion: vax-SPIRAL is safe, little reactogenic vaccine and has turned out to be an effective measure for leptospirosis control in individuals exposed to the risk of getting sick. Abstracts for SupplementInternational Journal of Infectious DiseasesVol. 14Preview Full-Text PDF Open Archive