Table 1.

Timeline of polio-related events in Ukraine.

Years	Events
1960–2005	Routine polio vaccination with tOPV; high coverage
1996	Last wild poliovirus case in Ukraine
2002	Ukraine certified free of poliovirus by the RCC along with other countries of the WHO European Region
Since 2005	Routine polio vaccination according to sequential schedule (2 doses of IPV at 2 and 4 months, followed by tOPV at 6 and 18 months and 6 and 14 years); high coverage until 2009
2008	Failed mass immunization campaign against measles and rubella
Since 2009	Sharp decline in coverage with polio and other vaccines, decline in vaccine acceptance
Since 2010	Ukraine ranked by the RCC as being at high risk of poliovirus spread if importation occurred
Since 2012	Problems with vaccine supply due to inefficient budgeting and vaccine procurement for the National Immunization Program
Since 2014	Economic and political crisis, military conflict with large numbers of displaced populations
2014	Poliovirus events: three isolated detections of VDPV2 (2 in Zakarpattya and one in Luhansk province) with no evidence of further circulation
2015	Polio outbreak: 2 polio cases due to highly divergent cVDPV1 in Zakarpattya
October 2015– February 2016	Three nationwide immunization rounds with tOPV implemented in response to the cVDPV1 outbreak
2015	Vaccine procurement legislation changed to allow for procurement via international agencies
2016	tOPV use in Ukraine discontinued from April 18, 2016 as part of the Global switch from tOPV to bivalent OPV (bOPV) in routine immunization program.

Abbreviations: tOPV, trivalent oral polio vaccine; bOPV, bivalent oral polio vaccine; IPV, inactivated polio vaccine; WPV, wild poliovirus; VDPV, vaccine-derived poliovirus; cVDPV, circulating VDPV; RCC, European Regional Certification Commission for Polio Eradication; WHO, World Health Organization.