Routine and mass administration of oral polio vaccine (OPV) since 1961 has prevented many millions of cases of paralytic poliomyelitis. The public health value of this inexpensive and easily administered product has been extraordinary. Progress of the Global Polio Eradication Initiative has further defined the value of OPV as well as its risk through vaccine-associated paralytic poliomyelitis (VAPP) and vaccine-derived polioviruses (VDPV). Although both are rare, once wild poliovirus transmission has been interrupted by OPV, the only poliomyelitis due to poliovirus will be caused by OPV. Poliovirus will be eradicated only when OPV use is discontinued. This paradox provides a major incentive for eventually stopping polio immunization or replacing OPV, but it also introduces complexity into the process of identifying safe and scientifically sound strategies for doing so. The core post eradication immunization issues include the risk/benefits of continued OPV use, the extent of OPV replacement with IPV, possible strategies for discontinuing OPV, and the potential for development and licensure of a safe and effective replacement for OPV. Formulation of an informed post eradication immunization policy requires careful evaluation of polio epidemiology, surveillance capability, vaccine availability, laboratory containment, and the risks posed by the very tool responsible for successful interruption of wild poliovirus transmission.

The goal of the World Health Organization is to stop routine use of oral poliovirus vaccine shortly after interruption of wild poliovirus transmission. A key component of this goal is to minimize the risk of reintroduction by destruction of polioviruses except in an absolute minimum number of facilities that serve essential functions and implement effective containment. Effective containment begins with a complete facility risk assessment. This article focuses on characterizing the risks of exposure to polioviruses from the essential vaccine production, quality control, and international reference and research facilities that remain. We consider the potential exposure pathways that might lead to a poliovirus reintroduction, including para-occupational exposures and releases to the environment, and review the literature to provide available estimates and a qualitative assessment of containment risks. Minimizing the risk of poliovirus transmission from a poliovirus facility to increasingly susceptible communities is a crucial and ongoing effort requiring understanding and actively managing the potential exposure pathways.

Effective control and eradication of diseases requires reliable information from surveillance activities, including laboratories, which typically incur real financial costs. This article presents data from a survey we conducted to estimate the costs of the Global Polio Laboratory Network (GPLN), which currently supports aggressive global surveillance for acute flaccid paralysis (AFP) to detect circulating polioviruses. The Global Polio Eradication Initiative (GPEI) of the World Health Organization (WHO) provides resources for some of the laboratory network costs, but the total cost of the network remains relatively poorly characterized given the limited documentation of national contributions. We surveyed network laboratories to quantify AFP surveillance support costs and provide data for cost estimates of potential posteradication surveillance policies related to the laboratories. We estimate that the GPLN currently requires millions (US dollars 2002) in total support annually, and that half of the support for national and regional reference laboratories comes from external donors through the WHO or bilateral agreements and half from within nations that host those laboratories. The article also presents the framework for considering the value of information from this global surveillance network and suggests that the expected value of surveillance information from the GPLN currently exceeds its costs. We also provided important insights about how the value of information may change after successful eradication of wild polioviruses.

TOC summary: These viruses can emerge independently where immunity to poliovirus is inadequate.

Summaryobjective To describe the epidemiology of rubella in Mozambique. methods Cross-sectional serosurvey of rubella IgG antibodies among women attending antenatal clinics in Maputo in February-April 2002 to assess the prevalence and titres.results Rubella IgG antibodies were detected in 95.3% (95% confidence interval 94.0%-96.6%) of 974 pregnant women. Age and residence did not significantly affect the prevalence of rubella IgG antibodies. However, the mean titre of rubella IgG antibodies was higher in women <20 years of age than in women ‡30 years of age (P < 0.01), and women living in urban areas had higher antibody titres than those living in suburban areas (P < 0.0001).conclusions The seroprevalence of rubella IgG antibodies among pregnant women in Maputo is high. Whether this is due to recent exposure to wild rubella virus or to exposure to rubella virus earlier in life is unclear. Studies on the burden of congenital rubella syndrome could address this matter.