History, Research, and Development  

Vaccine History


Innocuous Beginnings?

The earliest form of Leishmaniasis "vaccination" dates back hundreds of years. There is evidence that indicates that certain populations plagued by high prevalence of Leishmania infection attempted to induce immunity from further infection by a process known as Leishmaniazation. According to the WHO Initiative for Vaccine Research: Leishmaniasis site: "For centuries, in some of the hyper-endemic areas of the Middle East, the pus of an active lesion was used to inoculate young children to protect them against future lesions on the exposed parts of the body, especially the face." Leishmaniazation thus may be considered a crude pre-cursor of modern Leishmaniasis vaccine development. However, while Leishmaniazation may potentially be an effective means of infection prophylaxis for some individuals, there are risks associated with this process such as the development of persistent lesions that fail to heal. As such, given the advances in vaccination research, Leishmaniazation is not especially recommended.

PHOTO CAPTION: " A facial cutaneous leishmaniasis lesion on the nose of a young girl." - WHO/TDR/Crump

The Development of Modern Methodologies

In the first half of the 20th Century, researchers began to conduct clinical studies in the hopes of developing a vaccine for Leishmaniasis. As early as the 1930s, scientists in South America and Eastern Europe developed methods for the preparation of a Leishmaniasis vaccine comprised of multiple strains of dead Leishmania sp. Promastigotes. These early vaccines yielded a number of positive results. The early studies even suggested that a sufficient immuno-reaction to the developed vaccine would provide a substantial degree of protection against infection with minimal side effects. Many contemorporary clinical studies have attempted to expand upon the initial success of these earlier studies, however, because of a host of factors discussed in the RESEARCH section, progress has been hindered.

Looking to the Future...

Scientific innovation, technology, and advances in modes of production have effected changes in the ways in which scientists now think about developing a Leishmaniasis vaccine. Current vaccine innovation efforts have put a focus on novel antigens and adjuvants such as Alum, BCG (Bacillus Calmette-Guérin) and MPL (Monophosphoryl Lipid A), live-attenuated vaccines, recombinant antigens, plasmid DNA, bacteria expressing leishmanial antigens, Leishmania Activiated C-Kinase (LACK) and dendritic cells.

(L) "L
eishmaniasis vaccine production - a laboratory technician checking the stainless steel vats containing leishmaniasis vaccine" - WHO/TDR/Crump

(R) "Bottles of leishmaniasis vaccine produced in the Razi Institute, Teheran (IRAN) " - WHO/TDR/Crump