Vaccine-Associated Paralytic Poliomyelitis in the Postelimination Era in Latin America and the Caribbean, 1992–2011

Abstract

The Americas interrupted the transmission of poliovirus in 1991; most Latin American and Caribbean (LAC) countries rely on the oral polio vaccine (OPV) to maintain elimination. We estimated the risk of vaccine-associated paralytic polio (VAPP) in LAC for 1992–2011. VAPP cases were identified using LAC's acute flaccid paralysis (AFP) surveillance system. VAPP was defined as any AFP case with residual paralysis 60 days following onset that did not have a clear alternative etiology and with isolation of vaccine-strain poliovirus. Recipient VAPP cases were defined as those with paralysis onset 4–40 days following OPV; cases meeting these criteria but with unknown residual paralysis were added. Nonrecipient VAPP cases were defined as those in individuals with an unknown vaccination status, those in individuals who received 0 doses, or those with paralysis onset outside the 4–40-day interval. Of 40 926 AFP cases reported in LAC from 1992–2011, we identified 72 recipient and 119 nonrecipient VAPP cases. The estimated risk of recipient VAPP was 1 case per 3.15 million newborns (95% confidence interval [CI], 1 case per 2.56–4.10 million newborns), and the estimated overall risk was 1 case per 1.19 million newborns (95% CI, 1 case per 1.04–1.39 million newborns). In this multicountry VAPP analysis in a postelimination period, we found that the risk of VAPP in LAC was lower than previously estimated.