Before revision: Although contact immunity is an advantage of OPV, the risk of vaccine-associated paralytic poliomyelitis—affecting 1 child per 2.4 million OPV doses administered— lead the Centers for Disease Control and Prevention (CDC) to cease recommending its use in the US as of January 1, 2010, in favor of inactivated poliovirus vaccine (IPV).
After revision: Although contact immunity is an advantage of OPV, the risk of vaccine-associated paralytic poliomyelitis—affecting 1 child per 2.4 million OPV doses administered— led the Centers for Disease Control and Prevention (CDC) to cease recommending its use in the US as of January 1, 2010, in favor of inactivated poliovirus vaccine (IPV).