Poliomyelitis in modern conditions: Achievements and prospects
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01.01.2018 |
Ivanova O.
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Jurnal Infektologii |
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© 2018 Interregional public organization Association of infectious disease specialists of Saint-Petersburg and Leningrad region (IPO AIDSSPbR). All rights reservbed. The creation in the middle of the 20th century vaccines against poliomyelitis (PM) - inactivated vaccine (IPV) and live oral vaccine from Sabin strains (OPV) with various properties, advantages and disadvantages, but highly effective, made it possible to implement the idea of elimination of PM. Since 1988, the WHO Global Program of PM eradication has achieved remarkable success: the incidence of PM caused by wild poliovirus (PV) has been reduced by 10 thousand times, the number of endemic countries has been reduced to 3, the circulation of wild PV has been discontinued in 4 regions of the world the wild type 2 of PV has been eradicated, and wild type 3 of PV has not been detected for almost 5 years. Under conditions of a decrease in the incidence of PM caused by wild PV, the known negative properties of trivalent OPV made its further use problematic. These negative properties are: 1) the ability to cause post-vaccination complications and 2) the genetic instability of Sabin strains, especially PV of type 2, and their ability under certain conditions (primarily in conditions of low collective immunity to PV) to quickly restore neurovirulence, transforming into circulating vaccine-derived PV (VDPV), capable of causing incidents and outbreaks of PM. In order to reduce the risk associated primarily with type 2 PV, WHO proposed a global switch to the use of bivalent OPV from types 1 and 3, completed in 2016. In 2019, WHO plans to complete eradication of type 1 and 3 PVs, and in 2022 completely abandon the OPV. The precondition for the safety of such tactics is the maintenance of high collective immunity to PM. There are several threats to the security of this strategy. PVs can "silently" circulate in the human population for a long time without clinical manifestations of PM, which, with inadequate epidemiological surveillance can lead to the return of PM. The reintroduction of both wild PV and Sabin strains can occur from institutions that preserve / work with PV. The source of VDPV can be people with primary immunodeficiencies, which continuously excrete PV. It is necessary to maintain surveillance over the PM, expand additional types of surveillance for the PV, strict containment of all PVs. The only way to maintain collective immunity is immunization with trivalent IPV. The current global shortage of IPV poses a significant threat to the world's epidemiological well-being. The solution to the problem is the development of a new generation of safe and effective vaccines, improving the ways of introducing IPV, developing antiviral drugs.
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