Safety and immunogenicity of an autoclaved Leishmania major vaccine

Abstract

Objective: To test the safety and immunogenicity of two doses of autoclaved L. major (ALM) vaccine mixed with BCG. Setting: Kala-azar endemic area of eastern Sudan. Design: This was a randomised, double blind and BCG controlled phase I/II study. Subjects: Eighty healthy volunteers (forty children and forty adults) with no past history of kala-azar, no reactivity to leishmanin antigen and with a reciprocal direct agglutination test (DAT) titre of <200 were recruited. Informed consents were obtained from volunteers or their guardians in case of children. Main outcome measures: Conversion in the leishmanin skin and the DAT tests. Intervention: Two intra-dermal injections of either ALM+BCG or BCG alone. The injections were three weeks apart. Results: Side effects were minimal and confined to the injection site, with no significant difference between the ALM+BCG and the BCG alone groups. The leishmanin skin conversion was significantly higher in the ALM+BCG group compared to the BCG alone group (p<0.0005). Furthermore, the Leishmanin skin test conversion was significantly higher in children than adults (p<0.0005). One adult volunteer in the ALM+BCG group converted in both the Leishmanin skin and the DAT tests. Conclusion: We conclude that two doses of ALM+BCG are safe and immunogenic, especially in children.