Achieving Polio Eradication

To achieve global polio eradication, countries must improve emergency action strategies in order to vaccinate and access all populations and children, according to an update published in Morbidity and Mortality Week Report.

Since its inception in 1988, Global Polio Eradication Initiative, the transmission of wild poliovirus has been interrupted in all countries except Pakistan, Nigeria, and Afghanistan. Wild poliovirus type 2 was officially eradicated in 2015 and wild poliovirus type 3 has not been detected since 2012. Further, the occurrence of polio cases caused by circulating vaccine-derived poliovirus is rare and occurs where oral poliovirus vaccine coverage has been low. From 2017 to May 2019, 8 countries, including Democratic Republic of the Congo, Indonesia, Mozambique, Niger, Syria, Somalia, Nigeria, and Papua New Guinea, have reported 210 cases of circulating vaccine-derived poliovirus.

In the World Health Organization Africa Region, no cases of wild poliovirus type 1 have been detected in 30 months and continuing improvement in child vaccination and surveillance in Nigeria and northeast Africa countries suggest that wild poliovirus interruption may have been achieved. However, in spite of targeted efforts, in 2018 wild poliovirus case reports rose (33 cases) in Pakistan and Afghanistan in all previously identified reservoirs for the first time since 2014. These efforts attempted to increase immunization in security-compromised districts, reach highly mobile populations, and reduce vaccine refusal. This highlights the ongoing challenges of reaching children during supplemental immunization activities, surveillance of performance, and increasing accessibility of mobile populations at high risk in order to eradicate polio globally.

In Pakistan, specifically, goals include increasing the quality of supplemental immunization activities by more effectively engaging with communities to reduce the number of oral polio vaccine refusals and increase the immunization services demand, with a focus on local underperforming areas. Since rumors regarding the safety of the oral polio vaccine have significantly decreased effectiveness of recent supplemental immunization activities, risk communication and community engagement approaches need to be revised and implemented in the most affected districts starting with supplemental immunization activities in June. In Afghanistan, goals include renegotiating access to communities to overcome inaccessibility and engaging with local and religious leaders until house-to-house vaccination is reinstated. Finally, in response to circulating vaccine-derived poliovirus outbreaks to promptly stop transmission, programmatic improvements are necessary to improve response effectiveness and limit the risk for future outbreaks.

Overall, the study investigators concluded that, “Revised emergency action plans for each country provide the roadmaps to further intensify and improve program operations and will need to be fully implemented in every locality to ensure the successful eradication of polio.”

Reference

Greene SA, Ahmed J, Datta D, et al. Progress toward polio eradication — worldwide, January 2017-March 2019. MMWR. 2019;68(20):458-462.