Progress Toward Polio Eradication — Worldwide, 2013–2014

Edna K. Moturi, MBChB; Kimberly A. Porter, PhD; Steven G.F. Wassilak, MD; Rudolf H. Tangermann, MD; Ousmane M. Diop, PhD; Cara C. Burns, PhD; Hamid Jafari, MD

Disclosures

Morbidity and Mortality Weekly Report. 2014;63(21):468-472. 

In This Article

Discussion

Despite increases in cases since 2012, substantial progress toward polio eradication has occurred. No WPV3 case has been identified globally since November 2012 in Nigeria, raising the possibility that WPV3 transmission may have been interrupted globally. In March 2014, the WHO SEAR joined the WHO AMR, WPR and EUR as being certified free of indigenous wild poliovirus. With this achievement, 80% of the world's population now lives in WHO regions certified as polio-free. Indigenous WPV transmission within AFR and EMR, the two remaining WHO regions where polio is endemic, is now restricted to fewer geographical areas within each of the three remaining countries where polio is endemic than ever before. The decrease in the number of reported WPV cases and number of affected states and districts in Nigeria was associated with significantly improved SIA quality indicators during late 2012 and early 2013.[9] Current WPV transmission in Nigeria appears to be restricted to Kano and Borno states, although gaps in surveillance quality remain.

During 2010–2012, the conflict in Afghanistan prevented vaccinators from safely accessing children in many areas of the southern region of Afghanistan. However, systematic negotiations greatly improved access to children in 2013, which, together with successful efforts to improve the quality of SIAs, substantially reduced transmission of endemic WPV.[7] However, the success of global polio eradication is being challenged by major limitations in access and physical security within other countries.

In Pakistan, targeted attacks against polio workers and police officers assigned to protect them have seriously compromised the implementation of SIAs in parts of the Federally Administered Tribal Areas, Khyber Pakhtunkhwa province, and Karachi city. The continued ban on polio vaccination in North and South Waziristan, Federally Administered Tribal Areas where local leaders have prevented vaccination of >350,000 children since June 2012, is largely responsible for the increase in WPV cases in 2013 and 2014 in Pakistan and for recent WPV importation into Afghanistan and war-torn Syria. However, as of the end of April, 12 consecutive SIAs were carried out in 2014 already in Khyber Pakhtunkhwa province, demonstrating strong political commitment and engagement of local communities, religious leaders, and humanitarian organizations to reach unvaccinated children in these areas.[10]

Terrorist acts by antigovernment elements in Nigeria have prevented vaccinators from visiting some areas of Borno state since early 2013; however, vaccination access has gradually improved, and 84% of children were accessible by March 2014.

Limitations in access and physical security have also greatly affected the ability to promptly control and end outbreaks. Outbreak control has also been compromised by suboptimal SIA implementation, and incomplete understanding of outbreak dynamics resulting from variable AFP surveillance quality. The outbreak in the Horn of Africa has lasted >9 months after initial confirmation, partly caused by limitations in the quality of outbreak response in parts of Somalia not under government control and difficult-to-reach areas within Ethiopia. The ongoing circulation of WPV1 in Cameroon and Equatorial Guinea poses a risk for wider spread, including into populations affected by ongoing civil unrest in the Central African Republic; an aggressive outbreak response is being planned to include neighboring countries to limit further extension of transmission.

With further restriction of the geographic extent of WPV circulation in the countries where polio is endemic, and provided that outbreaks after importation into polio-free countries can be prevented or interrupted promptly, interruption of global transmission could be achieved in the near future. The GPEI has developed the Polio Eradication and Endgame Strategic Plan for 2013–2018§ to 1) interrupt all poliovirus transmission, 2) progressively withdraw OPV and introduce inactivated poliovirus vaccine, 3) certify polio eradication, and 4) transition assets and infrastructure to routine immunization programs as part of GPEI legacy.

The Director General of WHO has declared the recent international spread of WPV a public health emergency of international concern[5] and issued temporary recommendations under the International Health Regulations (IHR 2005) to reduce international exportation of WPV through 1) ensuring that residents and long-term visitors traveling from Cameroon, Pakistan, and Syria receive vaccination before international travel, and 2) encouraging residents and long-term visitors traveling from Afghanistan, Equatorial Guinea, Ethiopia, Iraq, Israel, Somalia, and Nigeria to receive vaccination before international travel and 3) ensuring that such travelers are provided an International Certificate of Vaccination documenting vaccination status. At this stage in the GPEI, enhanced commitment by countries and GPEI partners in a coordinated international effort is crucial to maintaining current gains and to complete polio eradication.

Global Polio Eradication Initiative Status Report. Available at http://www.polioeradication.org/Portals/0/Document/Aboutus/Governance/IMB/10IMBMeeting/2.2_10IMB.pdf.
§The Polio Eradication and Endgame Strategic Plan 2013–2018, available at http://www.polioeradication.org/Portals/0/Document/Resources/StrategyWork/PEESP_EN_US.pdf, is a comprehensive, long-term strategy that addresses what is needed to deliver a polio-free world by 2018.
Additional information is available at http://wwwnc.cdc.gov/travel.

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