Retrospective analysis of a local cessation of vaccination against poliomyelitis: a possible scenario for the future

Abstract

The global eradication of poliomyelitis will require substantial changes in immunization practices. One of the proposed scenarios includes cessation of vaccination with live oral poliovirus vaccine (OPV) and the creation of an OPV stockpile for emergency response in case of the reintroduction of poliovirus into circulation. We describe here a retrospective analysis of the cessation of OPV usage in a region of the Byelorussian Republic of the former Soviet Union in 1963 to 1966. During this period, a widespread circulation and evolution of independent lineages of vaccine-derived polioviruses took place in the region. Some of these lineages appeared to originate from OPV given to 40 children in the community during this period of essentially no vaccinations. The data demonstrate very high risks associated with both the local cessation of OPV vaccination and the proposed use of OPV to control a possible reemergence of poliovirus in the postvaccination period. The high transmissibility of OPV-derived viruses in nonimmune population, documented here, and the known existence of long-term OPV excretors should be also considered in assessing risks of the synchronized global cessation of OPV usage.

FIG. 1.

Isolation of poliovirus type 2 from unvaccinated children younger than 3 years old in the Mogilev District from May to October 1965. The arrow corresponds to the time of intentional limited introduction of OPV into six nurseries.

FIG. 2.

Genome structure of the isolates. (A) DNA oligonucleotide microarray analysis. The figures on the right side of the panel correspond to the serotype specificity of the oligonucleotide rows. (B) Schematic representation of the sequencing results. The Sab1 and Sab2 derived sequences are in red and blue, respectively. The sequence distantly related to the corresponding part of the P1W/Bar65 genome is in green, and the sequence of unknown origin is in yellow. The coordinates of the crossover sites are indicated.