This report reviews national surveillance data for all cases of confirmed paralytic poliomyelitis in the United States from 1990 through 2003 and assesses the effects of switching from oral poliovirus vaccine (OPV) to inactivated poliovirus vaccine (IPV). After OPV use began in 1961, an average of 9 cases of vaccine-associated paralytic poliomyelitis (VAPP) were confirmed each year from 1961–1989. The last case of poliomyelitis in the US due to indigenously acquired wild poliovirus occurred in 1979. National vaccination policy changed from sole reliance on OPV to the option of a sequential schedule of IPV followed by OPV in 1997. Exclusive use of IPV has been recommended since 2000.
From 1990 through 1999, 61 cases of paralytic poliomyelitis were reported. All but 2 that were of indeterminate etiology were VAPP (1 case per 2.9 million OPV doses). Thirteen cases were reported during the 3-year transition period. Each of these was associated with use of the all-OPV schedule; none were associated with the sequential IPV-OPV schedule. Since implementation of the all-IPV schedule in 2000, no cases of VAPP have been reported. The authors conclude that the move to the exclusive use of IPV has resulted in the elimination of VAPP from the US.
Financial Disclosure: Dr. Dubik has disclosed that he has no relationships relevant to this commentary.Financial Disclosure: Dr. Barton has disclosed that she has no relationships relevant to this commentary.
Once wild poliovirus disease was controlled in the US, the very small but real risk of VAPP began to outweigh the presumed advantages of OPV and led to calls for a safer vaccine. In 1987, an “enhanced potency” IPV was licensed.1 Ten years later the CDC endorsed the sequential IPV-OPV schedule while the AAP recommended it as an option.2 After additional cases of VAPP occurred in children who received the OPV-only schedule while none were noted with the IPVOPV schedule, the CDC, AAP, and AAFP agreed to move to an all-IPV schedule.3,4 The policy changes have achieved their objectives. An accompanying editorial discusses the dangers of vaccine-derived poliovirus5,6 and the challenge of moving away from OPV globally.7
This article is a testimony to the impact of the change from OPV to IPV in the US. Graying experts still debate whether or not the putative benefits of OPV ever outweighed its risks in hygienic societies such as the US, and whether the switch from live to inactivated vaccine was timely or perhaps over a decade and 100 cases of paralytic disease late. In 1988, an IOM expert committee recommended consideration of a sequential schedule and a change to IPV when a DTP-IPV combination was available, then anticipated within 2–5 years.8 Widespread use of OPV has led to the elimination of wild-type polio in most of the world, but final eradication of paralytic disease will...