Inactivated poliovirus vaccine campaign in Kenya: Lessons learned

摘要

Kenya has been free of polio since 2006. But it experienced several importations of wild poliovirus (WPV) causing outbreaks in 2009, 2011 and 2013. The latest reintroduction was the 2013 Horn of Africa WPV1 outbreak, which started in neighbouring Somalia in April 2013. A total of 217 children were paralysed in that outbreak; of which, 14 were in Dadaab, northeast Kenya. The Dadaab area also experienced an outbreak of circulating vaccine-derived poliovirus type 2 (cVDPV2) in 2012, genetically linked to a similar outbreak in Somalia. Despite the ongoing polio campaigns and routine immunization, pockets of immunity gaps among under fives in these countries are believed to be a catalytic factor that enables poliovirus circulation following an importation event.