POLIO [to 21 November 2015]
Public Health Emergency of International Concern (PHEIC)

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GPEI Update: Polio this week as of 17 November 2015
http://www.polioeradication.org/Dataandmonitoring/Poliothisweek.aspx
:: In 2015, wild poliovirus transmission is at the lowest levels ever, with fewer cases reported from fewer areas of fewer countries than ever before. In 2015, 56 wild poliovirus cases have been reported from two countries (Pakistan and Afghanistan), compared to 290 cases from nine countries during the same period in 2014.

:: However, in the end stages of polio eradication, with most of the world polio-free, the risks posed remaining vaccination coverage gaps anywhere is becoming more evident. On extremely rare occasions, in areas of chronic vaccination coverage gaps, circulating vaccine-derived polioviruses (cVDPVs) can emerge to cause outbreaks of polio cases. This is not a side effect of the oral polio vaccine, but rather an effect of low vaccination coverage in a community, which is enabling such strains to emerge. Though typically less virulent than wild polioviruses (ie typically causing fewer cases and having a lower profile for geographic spread), such strains nevertheless are this year causing paralysis in children at a rate greater than wild polioviruses. More countries are affected by cVDPV outbreaks (Ukraine, Guinea, Lao, Nigeria, Madagascar) than wild polioviruses (Pakistan and Afghanistan); 3 WHO Regions are affected by cVDPV outbreaks.

:: Efforts are ongoing by the Global Polio Eradication Initiative to urgently address both remaining wild poliovirus transmission and cVDPV outbreaks. This is particularly important in the lead-up to next year’s start of the phased removal of OPVs, beginning with the globally-coordinated switch from trivalent OPV to bivalent OPV in April 2016.

[Selected elements from Country-level reports]
Afghanistan
:: Three new wild poliovirus type 1 (WPV1) cases were reported in the past week, from Faryab and Nangahar provinces. The most recent case had onset of paralysis on 27 October, from Nangahar. The total number of WPV1 cases for 2015 is 16.
:: One new WPV1 environmental positive sample was reported in the past week, collected on 25 October from Wardad.
:: Urgent efforts are underway to strengthen the implementation of the national emergency action plan in the country. Focus is on:
– Improving governance and coordination of partners through the National and Provincial Emergency Operations Centres
– Improving SIA quality by focusing resources on low-performing districts, and clearly identifying and targeting persistently missed children
– Maximising the impact of front-line health workers through more systematic vaccinator selection, training and supervision
– Ensuring closer cross-border coordination in border areas with Pakistan
– Further strengthening surveillance, including by expanding environmental surveillance activities
:: National Immunization Days (NIDs) took place on 1 – 3 November using trivalent oral polio vaccine (OPV). Mop up campaigns are planned in areas of Farah using inactivated polio vaccine (IPV) and bivalent OPV with dates to be confirmed, and Subnational Immunisation Days (SNIDs) are planned from 29 November to 1 December in the south and east of the country using bivalent OPV.
Pakistan
:: One new wild poliovirus type 1 (WPV1) case was reported in the past week, with onset of paralysis on 22 October. It is the most recent WPV1 case in the country, from Peshawar in Federally Administered Tribal Areas (FATA). The total number of WPV1 cases for 2015 is 40.
:: Two new type 2 circulating vaccine-derived poliovirus (cVDPV2) cases were retrospectively reported this week. The cases had onset of paralysis in February, from Khyber Paktunkhwa and FATA. No further cases have been identified since then, and the areas were covered by three vaccination campaigns with trivalent OPV.
:: One new environmental sample positive for WPV1 was reported in the last week, from Gadap, greater Karachi, Sindh, collected on 13 October.
:: September and October have historically been the months with the highest disease burden, as it is in the middle of the high transmission season. Epidemiologists are further evaluating data from this year, to more clearly ascertain current transmission patterns during this year’s high transmission season. This year, six WPV1 cases were reported during September and October, compared to 79 WPV1 cases in September/October 2014.