NEW THIS TUESDAY: POLIO OUTBREAK IN SOMALIA AND KENYA

Saturday, 24th of August 2013

POLIOMYELITIS OUTBREAK IN SOMALIA AND KENYA

Excerpt below; full text is at http://www.who.int/wer/2013/wer8833.pdf

Discussion

The current outbreak in the Horn of Africa is likely to be large, of long duration, and to spread rapidly. For the past 3 years, immunization activities in some regions of Somalia have been significantly constrained by ongoing conflict and insecurity. Over time, this has led to the build-up of a large susceptible population of children. At the beginning of the outbreak it was estimated that around 600 000 children <5 years of age were living in areas that had not been reached for the past 3 years by large scale-immunization activities.

Furthermore, throughout the first 2 months of the outbreak response, conflict has continued to limit the reach of vaccination teams. Joint WHO and UNICEF estimates indicate that the coverage of 3 doses of OPV through routine immunization in Somalia in 2012 was only 47%,

indicating the presence of a large cohort of susceptible children in the country.4

The detection of WPV in both South-Central and North Somalia and Eastern Kenya, and most likely in the Somali Province of Ethiopia, shows that transmission has extended over large geographical distances. During the large international polio outbreak in 2005, multiple

countries in the Horn of Africa were affected including Eritrea, Ethiopia, Kenya, Somalia and Yemen, resulting in >700 cases of paralytic poliomyelitis. Therefore, the Global Polio Eradication Initiative (GPEI) is creating localized plans to maximize opportunities to

vaccinate children in areas where access is limited by conflict and insecurity.

Globally, this is the first reported large-scale WPV outbreak since the WPV1 outbreak that was reported in China in August 2011. It demonstrates the ongoing threat of WPV spread to polio-free countries that will persist until WPV transmission is stopped in the remaining endemic countries. The risk of a large and explosive outbreak following introduction of WPV is much higher in areas affected by prolonged conflict and complex humanitarian emergencies where there are large cohorts of susceptible children. But despite protracted conflict spanning decades, the programme in Somalia has been successful in stopping transmission of indigenous WPV in 2002 and subsequently was able to stop transmission in 2007 during the large multicountry polio outbreak in the Horn of Africa. This experience indicates that with a strong and well coordinated response it is feasible to terminate the

current WPV outbreak in Somalia.

The outbreak responses in Somalia and Kenya have been exceptionally rapid and intensive. Notably, special strategies have been employed to limit transmission and spread of WPV such as short-interval, expanded age group campaigns, mostly using the bOPV which is

more efficacious against WPV1 than the trivalent OPV.

The first SIA in Somalia was conducted within 6 days after notification of the first WPV case. International collaboration for the outbreak response has enabled outbreak-affected and at-risk countries to synchronize and coordinate their efforts in order to strengthen the

overall impact of the response.

Ongoing insecurity is a continuing challenge to the quality of the campaigns being conducted in Somalia. For this reason, vaccination posts have been set up at key transit points to immunize hard-to-reach populations. The involvement of communities, their leaders and local authorities in conflict-affected and insecure areas is essential to maximize the

opportunities to vaccinate all children in Somalia.

Efforts are ongoing to ensure that the support of all local stakeholders is aligned and the polio outbreak is rapidly brought under control in all areas of Somalia.