POLIO: NEW CHALLENGES ON THE WAY TO ERADICATION

Abstract

SUMMARY. Despite the undeniable progress on the implementation of the Global Initiative eradication of poliomyelitis (polio cases have decreased by over 99,9 % since 1988, the cessation of circulation «wild» polioviruses types 1 and 3, the number of polio-endemic countries had decreased from 125 to 3, etc.), a number of outstanding issues remain that prevents the achievement of the ultimate goal (the continued circulation of the «wild» poliovirus type 1, the formation of vaccine derived polioviruses (VDPVs) and associated risks, cases of vaccine associated paralytic poliomyelitis (VAPP), gaps in immunization programs of certain countries and others. In 2015 in Ukraine there was an outbreak of poliomyelitis caused circulating VDPV1 (cVDPV1). This happened against the backdrop of years of decline coverage planned vaccination against poliomyelitis (for example, in 2014 ‒ 44.7 %, 7 months of 2015 ‒ 17.3 %). This contributed to the accumulation of non-immune interlayer among children and the formation VDPVs. In response to the polio outbreak was conducted three rounds of immunization by OPV. However, their levels were inadequate (respectively 64.4 %, 71.7 % and 80.7 % compared with the required 95 %). At the same time, the results of surveillance showed high probability of termination circulation cVDPV1.