Elimination Of Wild Polioviruses Research Articles

Vacunas antipoliomieliticas, erradicación y posterradicación

Vaccination against polio generates herd immunity (both with the attenuated (OPV) and inactivated (IPV) vaccines) and this will allow the eradication of the disease. The OPV vaccine produces 2-4 polio cases per cohort of one million children and therefore IPV is used in countries that can afford its cost (about 15 times more expensive than OPV). In 1988 the World Health Assembly established the polio eradication goal as "interruption of wild poliovirus transmission". If the elimination of wild poliovirus were achieved, the use of OPV will produce annually between 250 and 500 cases of polio in the world. From 1999, it was clear that eradication would require ending of immunization with OPV. On the 25th of January, 2013 it is approved the plan for the eradication and containment of all polioviruses, wild or not, so that no child suffers paralytic poliomyelitis. The most important landmarks include the lack of wild polio cases after 2014, the introduction of at least one dose of IPV in all immunization programs and to cease the type 2 OPV vaccination by the end of 2016 and to stop the use of the oral bivalent vaccine in 2019. To achieve all this, a complex scientific work and economic solidarity will be required.

India's Poliomyelitis Eradication: A Milestone in Public Health

India has recently completed 2 years without single case of poliomyelitis on 13 January 2013. This has brought South East Asian Region closer to eradication. Recently, India is being regarded as a role model for polio eradication efforts in other low-income endemic countries-Pakistan, Nigeria and Afghanistan. However, the near elimination of wild polio virus in India has set forth newer challenges. Stricter surveillance measures are now needed to check for importations spread of virus in migratory populations and rapid containment of newly found virus. India's battle against polio will soon be cited as biggest public health achievement or most expensive public health failure.

Poliomyelitis eradication: Rhetoric or reality

Since the launch of Global Polio Eradication Initiative in 1988, disease burden has been reduced by more than 99% globally. Lately, India has witnessed a year without a case of poliomyelitis. It no longer stands endemic and is being regarded as a model for polio eradication efforts in other low income endemic countries: Pakistan, Nigeria and Afghanistan. The near elimination of wild polio virus in India has set forth new challenges of vaccine derived polio virus and need for newer strategies in oral poliomyelitis vaccine cessation preparatory phase. Stricter surveillance measures are needed to check for importations, any spread of virus in migratory populations and rapid containment of newly found virus. No stone should be left unturned in this last ditch effort for extermination of polio virus form environmental circulation. India's battle against polio will be cited as the biggest public health achievement or the most expensive public health failure.

Polio eradication strategies in India Successes, concerns & future perspectives

Abstract Polio Eradication Initiative (GPEI) was launched in 1988 with a multinational effort (World Health Assembly resolution) to control, eliminate and eradicate Poliomyelitis from the world by 2008. Prior to 1988, 3,50,000 children were getting paralyzed due to Poliomyelitis. The objective was to achieve global immunity against wild polio viruses (WPVs) by the year 2008. By the year 2000, there were only 2971 confirmed cases with the elimination of P2 Virus since 1999. Polio incidence remained around 2000 cases a year. During the years 2000–2007, there was a mixture of success and unanticipated set backs, viz. there was a continued reduction in the number of Polio cases but continued circulation of the Polio Virus in the four Polio endemic countries—India, Pakistan, Afghanistan and Nigeria. By the year 2009, 210 Countries were Polio free, of which 134 were certified and there were only 1606 cases in 4 endemic countries with 23 infected countries. The Advisory Committee On Polio Eradication (ACPE) initiated the “Program of Work 2009” and the “Strategic Plan 2010–2012”. As of 1st June, in 2010, only 21 Cases were reported from India (WPV1–3 & WPV3–18) as against 59 cases for the corresponding period in 2009. 2 cases, due to cVDPV2, were reported from UP. bOPV 1 & 3 were introduced in the endemkic zones of western UP and Kosy river belt in Bihar since January 2010. This is an encouraging trend for the first time in 22 years since the inception of GPEI. The interruption of WPV 3 could happen by the low force of transmission (FoT) season of 2011. The hope is that by 2011, India would achieve the elimination of WPVs 1&3. Since Polio eradication means the elimination of both wPV and vDPV, India should move to the bOPV 1&3 — eIPV sequential / exclusive eIPV schedule, as recommended by the India Experts Advisory Group (IEAG), in future even in the pre eradication phase and continue the same strategy in the post eradication phase as guided by the WHO. By all positive signals, India could obtain “Polio free certification” from the World Health Organization (WHO) by the year 2015.

Vaccine-associated paralytic poliomyelitis in Japan

Despite WHO's recommendation to switch the poliomyelitis vaccine from oral polio vaccine (OPV) to inactivated polio vaccine (IPV) in countries where polio elimination has been achieved, Japan has continued to use OPV. In Japan, OPV is given twice to children aged from 3 to 18 months.1 More than 10 years after the elimination of wild polio virus, tragic cases of vaccine-associated paralytic poliomyelitis (VAPP) continue to be reported every year—most recently in May, 2011. The Ministry of Health, Labour and Welfare claims that IPV is still being developed by Japanese vaccine companies and that it will not be available until the end of 2012 at the earliest. The growing tension between the Government, which persists with domestically produced OPV, and the parents, who request IPV to avoid VAPP, has evoked huge media attention.

Path to polio eradication in India: A major milestone

The global polio eradication initiative was established in 1988 by the World Health Organization to achieve eradication of wild polioviruses (WPVs) by the year 2000. More than a decade later India achieved a major milestone when in 2012 it crossed one full year without any WPV detection. India’s achievement is positive encouragement for GPEI and a sign of hope that global eradication is achievable. Technically the absence of WPV for three years in the face of high quality surveillance is necessary for global acceptance of elimination. However the quality of India’s surveillance is exemplary as supported by the evidence of improved antibody prevalence in infants. Several agencies contributed to this success – GPEI Immunization Division of the Ministry of Health Uttar Pratesh and Bihar State Governments district personnel health workers and families. Success can be attributed to several factors including sustained intensive vaccination programs diligence in finding and vaccinating children of migrant families and the use of monovalent and bivalent oral polio vaccines (OPVs). In guiding India’s future plans for action concerns about complacency and transmission must be kept in mind. The risk of undetected WPV circulation is especially important when targeting migrant mobile and underserved communities. Though a globally firm strategy for the immediate post-WPV eradiation phase has not been finalized options are currently being discussed and debated. The GPEI has been exploring ways to reduce the cost of inactivated poliovirus vaccine after which the government must be prepared to introduce to achieve high coverage after the elimination of WPVs in India.