POLIO [to 13 February 2016]
Public Health Emergency of International Concern (PHEIC)
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Polio this week as of 10 February 2016
:: As we enter February 2016, GPEI bids farewell to Hamid Jafari, the former director of GPEI, whose tenure has seen the removal of Nigeria from the list of polio-endemic countries, certification of the eradication of wild poliovirus type 2, and the lowest number of cases reported in the fewest number of places in any one year. GPEI welcomes Michel Zaffran, former coordinator of the WHO Expanded Programme on Immunization (EPI), as its new director, as we enter a pivotal part of the Endgame Plan.
:: Iraq has introduced the inactivated poliovirus vaccine (IPV) into its routine immunization system. Read more here.
:: Environmental surveillance is playing an increasingly important role in ensuring that the poliovirus is found, wherever it continues to circulate. Find out more about environmental surveillance through this series of photographs.
:: There are nine weeks to go until the globally synchronized switch from the trivalent to bivalent oral polio vaccine, an important milestone in achieving a polio-free world. Read more here.
Selected content from Country updates
Afghanistan
:: One new wild poliovirus type 1 (WPV1) case was reported in the past week, with onset of paralysis in Shahwalikot, Kandahar, on 20 December 2015. The total number of WPV1 cases for 2015 is now 20, compared to 28 reported in the country in 2014.
Pakistan
:: The first case of wild poliovirus type 1 (WPV1) in 2016 was reported in the past week, with onset of paralysis in Karachi Gadap, Sindh on 17 January 2016. The total number of WPV1 cases for 2016 is now 1, compared to 7 reported for 2015 at this point last year.
Lao People’s Democratic Republic
:: Two new cases of circulating vaccine-derived poliovirus type 1 (cVDPV1) were reported in the past week, in Phonhong and Fueng, Vientiane, with onset of paralysis on 8 January and 11 January 2016 respectively. The total number of cVDPV1 cases in 2016 is 2.

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Notes from the Field: Circulating Vaccine-Derived Poliovirus Outbreaks — Five Countries, 2014–2015
MMWR Weekly / February 12, 2016 / 65(05);128–129
Michelle Morales, MD1,2; Chimeremma D. Nnadi, MD, PhD2; Rudolf H. Tangermann, MD3; Steven G.F. Wassilak, MD2 (View author affiliations)
[Initial text]
In 2015, wild poliovirus (WPV) transmission was identified in only Afghanistan and Pakistan (1). The widespread use of live, attenuated oral poliovirus vaccine (OPV) has been key in polio eradication efforts. However, OPV use, particularly in areas with low vaccination coverage, is associated with the low risk for emergence of vaccine-derived polioviruses (VDPV), which can cause paralysis (2). VDPVs vary genetically from vaccine viruses and can cause outbreaks in areas with low vaccination coverage. Circulating VDPVs (cVDPVs) are VDPVs in confirmed outbreaks. Single VDPVs for which the origin cannot be determined are classified as ambiguous (aVDPVs), which can also cause paralysis. Among the three types of WPV, type 2 has been declared to be eradicated. More than 90% of cVDPV cases have been caused by type 2 cVDPVs (cVDPV2). Therefore, in April 2016, all OPV-using countries of the world are discontinuing use of type 2 Sabin vaccine by simultaneously switching from trivalent OPV (types 1, 2, and 3) to bivalent OPV (types 1 and 3) for routine and supplementary immunization.

The World Health Organization recently broadened the definition of cVDPVs to include any VDPV with genetic evidence of prolonged transmission (i.e., >1.5 years) and indicated that any single VDPV2 event (a case of paralysis caused by a VDPV or isolation of a VDPV from an environmental specimen) should elicit a detailed outbreak investigation and local immunization response. A confirmed cVDPV2 detection should elicit a full poliovirus outbreak response that includes multiple supplemental immunization activities (SIAs); an aVDPV designation should be made only after investigation and response (3). Since 2005, there have been 1–8 cVDPV outbreaks and 3–12 aVDPV events per year. There are currently five active cVDPV outbreaks in Guinea, Laos, Madagascar, Myanmar, and Ukraine, and four other active VDPV events…