Progress toward polio eradication--Somalia, 1998-2013

Abstract

Since the 1988 resolution of the World Health Assembly to eradicate polio, significant progress has been made toward achieving this goal, with the result that only Afghanistan, Nigeria, and Pakistan have never successfully interrupted endemic transmission of wild poliovirus. However, one of the greatest challenges of the Global Polio Eradication Initiative has been that of maintaining the polio-free status of countries in unstable regions with weak healthcare infrastructure, a challenge exemplified by Somalia, a country in the Horn of Africa region. Somalia interrupted indigenous transmission of wild poliovirus in 2002, 4 years after the country established its national polio eradication program. But political instability and protracted armed conflict, with significant disruption of the healthcare system, have left Somalia vulnerable to 2 imported outbreaks of wild poliovirus. The first occurred during 2005-2007, resulting in >200 cases of paralytic polio, whereas the second, which began in 2013, is currently ongoing. Despite immense challenges, the country has a sensitive surveillance system that has facilitated prompt detection of outbreaks, but its weak routine immunization system means that supplementary immunization activities constitute the primary strategy for reaching children with polio vaccines. Conducting vaccination campaigns in a setting of conflict has been at times hazardous, but the country's polio program has demonstrated resilience in overcoming many obstacles to ensure that children receive lifesaving polio vaccines. Regaining and maintaining Somalia's polio-free status will depend on finding innovative and lasting solutions to the challenge of administering vaccines in a setting of ongoing conflict and instability.

Keywords: Somalia; acute flaccid paralysis (AFP); disease eradication; immunization; oral polio vaccine (OPV); polio; surveillance; wild poliovirus (WPV).

Figure 1

Map of Somalia Showing Geopolitical (Administrative) Zones and Regions

Figure 2

Epidemic Curve of AFP Cases in Somalia with Line Graph of Non-Polio AFP Rate during 1998–2013 Abbreviations and AFP Case Definitions AFP: Acute flaccid paralysis WPV: Wild poliovirus cVDPV: Circulating vaccine-derived poliovirus npAFP: Non-polio AFP Compatible: AFP cases lacking adequate stool specimens but having residual paralysis or a pattern of clinical presentation consistent with polio after 60 days of onset Discarded: AFP cases with adequate stool specimens but testing negative for poliovirus, or lacking adequate stool specimens and not having residual paralysis or a pattern of clinical presentation consistent with polio after 60 days of onset Pending: AFP cases pending final classification

Figure 3

Bar Graph Showing Immunity Profile of AFP Cases with Line Graphs of Routine and Supplementary Immunization (Mean) Coverage, Somalia 1998–2012.

Figure 4

Distribution of Polio Supplementary Immunization Activities (SIAs) by Year and Zone, Somalia 1998–2012.