The Global Polio Laboratory Network as a Platform for the Viral Vaccine-Preventable and Emerging Diseases Laboratory Networks.

The Global Polio Laboratory Network (GPLN) began building in the late 1980s on a 3-tiered structure of 146 laboratories with different and complementary technical and support capacities (poliovirus isolation, molecular strain characterization including sequencing, quality assurance, and research). The purpose of this network is to provide timely and accurate laboratory results to the Global Polio Eradication Initiative. Deeply integrated with field case-based surveillance, it ultimately provides molecular epidemiological data from polioviruses used to inform programmatic and immunization activities. This network of global coverage requires substantial investments in laboratory infrastructure, equipment, supplies, reagents, quality assurance, staffing and training, often in resource-limited settings. The GPLN has not only developed country capacities, but it also serves as a model to other global laboratory networks for vaccine-preventable diseases that will endure after the polio eradication goal is achieved. Leveraging lessons learned during past 27 years, the authors discuss options for transitioning GPLN assets to support control of other viral vaccine-preventable, emerging, and reemerging diseases.

Vaccine-derived polioviruses and the endgame strategy for global polio eradication.

As the global eradication of wild poliovirus nears, the World Health Organization (WHO) is addressing challenges unprecedented in public health. The live, attenuated oral poliovirus vaccine (OPV), used for more than four decades to interrupt poliovirus transmission, and the vaccine of choice for developing countries, is genetically unstable. Reversion of the small number of substitutions conferring the attenuated phenotype frequently occurs during OPV replication in humans and is the underlying cause of the rare cases of vaccine-associated paralytic poliomyelitis (VAPP) in OPV recipients and their close contacts. Whereas VAPP has long been recognized, two other adverse events have been identified more recently: (a) long-term excretion of highly evolved vaccine-derived polioviruses (VDPVs) in persons with primary immunodeficiencies, and (b) polio outbreaks associated with circulating VDPVs in areas with low rates of OPV coverage. Developing a posteradication strategy to minimize the risks of VDPV emergence and spread has become an urgent WHO priority.

Prolonged detection of indigenous wild polioviruses in sewage from communities in Egypt.

Environmental surveillance for polioviruses has been implemented in Egypt. This paper reports on a study in which 130 sewage samples were collected between January 2001 and December 2001 from eight provinces of Egypt. Samples were analyzed by virus isolation in L20B and RD cell cultures, and wild polioviruses were characterized by sequencing of the VP1 protein coding region. Wild type 1 polioviruses were detected in 57% of the sewage samples and 91% of the study sites, only two of which reported paralytic poliomyelitis cases in 2001. Three genetic lineages of a single indigenous type 1 poliovirus genotype were detectable in sewage, and only one lineage was also detected through surveillance for acute flaccid paralysis. Wild polioviruses persisted in the environment despite implementation of oral poliovirus vaccine immunization campaigns. Continued analysis of sewage samples, critical evaluation of immunization coverage, and performance of surveillance for acute flaccid paralysis are proposed as follow-up activities.