An Outbreak of Wild Poliovirus in the Republic of Congo, 2010-2011

The Global Polio Eradication Initiative began in 1988 with the goal of interrupting all wild poliovirus (WPV) transmission. Progress continues, but poliomyelitis remains endemic in Nigeria, Afghanistan, and Pakistan [1]. In addition, outbreaks due to importations have occurred in countries where indigenous WPV transmission had been interrupted, such as in Tajikistan, Ivory Coast, and China in 2010–2011 [2–4]. In some countries that had achieved the goal of interrupting WPV transmission, such as Angola, Chad, and the Democratic Republic of Congo (DRC), importations have resulted in ongoing, reestablished transmission, creating the threat of WPV spread to other polio-free countries. The Expanded Programme on Immunization began in the Republic of Congo (ROC) in 1981. However, civil unrest during 1993–2003, including a civil war in 1997–1999, disrupted routine immunization services for multiple birth cohorts. The recommended routine schedule includes 4 doses of trivalent oral polio vaccine (tOPV) administered at birth and at 6, 10, and 14 weeks of age. National reported routine immunization coverage for ≥3 doses of tOPV3 rose from 42% in 1980 to 90% in 2010; however, tOPV3 coverage dropped to 20% during the civil unrest in 1993–2003 (Figure 1) [5]. In 2010, administrative tOPV3 coverage of 90% was reported among 1-year-olds; however, a survey found tOPV3 coverage to be 68% [6]. Supplementary immunization activities (SIAs) targeting children aged