This Week

Polio this week as of 22 February 2017

  • Summary of newly-reported viruses this week (see country-specific sections below for further details): Afghanistan – one wild poliovirus type 1 (WPV1) case and one environmental WPV1 positive sample; Pakistan – one WPV1 case and environmental WPV1 positive sample.

NA: onset of paralysis in most recent case is prior to 2015. Figures exclude non-AFP sources. Lao PDR cVDPV1, all others cVDPV2. cVDPV definition: see document “Reporting and classification of vaccine-derived polioviruses” at [pdf]

Weekly country updates as of 22 February 2017

  • One new wild poliovirus type 1 (WPV1) case was reported in the past week from Nahr-e-Saraj district, Helmand province, with onset of paralysis on 21 January. The total number of WPV1 cases for 2016 remains 13, and two for 2017.
  • One new environmental WPV1 positive sample was reported in the past week from Jalalabad, Nangarhar, collected on 24 January
  • Most areas of Afghanistan are without polio cases, but wild poliovirus continues to circulate in localized geographical areas in the Eastern and South Eastern Regions of the country. Two geographical areas are of particular importance:  Bermel district in Paktika province, and Sheegal district in Kunar, which have reported 11 of the 13 polio cases in 2016.
  • Afghanistan and Pakistan continue to be treated as a single epidemiological block.
  • One new wild poliovirus type 1 (WPV1) case was reported in the past week from Lodhran district, Punjab province, with onset of paralysis on 28 January 2017. This is the first case in Punjab since December 2015, and an immunization response is already being implemented.
  • One new environmental WPV1 positive sample was reported in the past week, from Quetta, Balochistan, collected on 20 January.
  • The year 2016 saw the lowest ever annual number of polio cases in the country but poliovirus continues to be isolated through environmental surveillance over a significant geographical range.
  • Efforts continue in Quetta Block to strengthen programme operations as well as supervision and monitoring mechanisms to stop transmission of WPV1 and VDPV2.
  • The Prime Minister’s Focus Group on Polio Eradication convened on 20 February, reviewing the current program situation and agreeing on a way forward to ensure high quality operations for the rest of the low transmission season.
  • No new cases of wild poliovirus type 1 (WPV1) were reported in the past week.  The total number of WPV1 cases for 2016 remains four.  The most recent case had onset of paralysis on 21 August in Monguno Local Government Area (LGA), Borno.
  • Nigeria continues to implement emergency outbreak response, in response to the detected WPV1 strain and circulating vaccine-derived poliovirus type 2 (cVDPV2) strains affecting the country.
  • The response is part of a broader regional outbreak response, coordinated with neighbouring countries, in particular the Lake Chad sub-region, including northern Cameroon, parts of Central African Republic, Chad and southern Niger.
  • Detection of the cases of polio underscores the risk posed by low-level undetected transmission and the urgent need to strengthen subnational surveillance.
  • The detection of wild poliovirus type 1 (WPV1) and circulating vaccine-derived poliovirus type 2 (cVDPV2) in Nigeria poses a risk to the neighbouring countries of the Lake Chad basin and hence an outbreak response plan is being implemented as part of the response to the Nigeria outbreak.
  • Emergency outbreak response efforts continue across the Lake Chad basin, together with activities to fill subnational surveillance gaps across the region.
  • No circulating vaccine-derived poliovirus type two (cVDPV2) cases have been reported from Guinea in 2016 or 2017. The most recent case was reported from Kankan district with onset of paralysis on 14 December 2015. The total number of cVDPV2 cases for 2015 is seven.
  • While it has been more than a year since the last case had onset of paralysis in Guinea, undetected circulation cannot be ruled out.  A recently-conducted surveillance review in the country found significant improvements to surveillance sensitivity, though some remaining subnational gaps.
  • No new cases of circulating vaccine-derived poliovirus type one (cVDPV1) were reported in the past week. The most recent case was reported in Fuang district of Vientiane province, with onset of paralysis on 11 January 2016. The total number of cVDPV1 cases remains three in 2016 and eight in 2015.
  • Outbreaks of cVDPVs can arise in areas with low population immunity, emphasizing the importance of maintaining strong vaccination coverage.