[Anti-plague vaccination: past and future perspectives]

The impact of the three historic plague pandemics will remain engraved forever in the collective memory. During the first half of the XXth century, the development of vaccines inducing protection against bubonic plague, the first production of antibiotics, insecticides and raticides, could have lead some people to think that eradication was possible. But according to the data of epidemiological surveillance, far from disappearing, plague is remaining or so increasing that it is considered, in some places, as a reemerging disease. Yersinia pestis is highly variable, and a multidrug resistant strain has been isolated in 1995 in the Ambalavo district of Madagascar. This high-level of resistance includes the drugs recommended for plague prophylaxis and therapy, and this observation pointed the fact that Yersinia pestis is able to acquire the plasmid carrying the resistance genes, under natural conditions. Consequently, it is not unreasonable to think that clinically ominous events could occur again. Moreover, currently available vaccines do not induce protection against the pneumonic form of plague, and are reactogenic. Lastly, according to some accurate sources, one cannot turn down the assumption of a genetically engineered strain of Yersinia pestis used as a biological weapon by a terrorist organization. So, the surveillance of plague remains a topical activity, as the development of none reactogenic live and/or inactivated new vaccines, inducing protection against the pneumonic form of the disease.