Rudolf H. Tangermann

Certification of polio eradication: process and lessons learned.

Since the 1988 World Health Assembly resolution to eradicate poliomyelitis, considerable progress has been made towards interrupting the transmission of wild poliovirus globally. A formal process for the certification of polio eradication was established on the basis of experience gained during smallpox eradication. Independent groups of experts were designated at the global, regional, and country levels to conduct the process. The main requirements for the global certification of the eradication of wild poliovirus are the absence of wild poliovirus, isolated from suspect polio cases, healthy individuals, or environmental samples, in all WHO regions for a period of at least three years in the presence of high-quality, certification-standard surveillance and the containment of all wild poliovirus stocks in laboratories. Three WHO regions--the Region of the Americas (1994), Western Pacific Region (2000), and European Region (2002)--have already been certified free of indigenous wild poliovirus. Eradication and certification activities are progressing well in the three endemic regions (African, Eastern Mediterranean, and South-East Asia). Several challenges remain for the certification of polio eradication: the need for even closer coordination of certification activities between WHO regions, the verification of laboratory containment, the development of an appropriate mechanism to verify the absence of circulating vaccine-derived polioviruses in the future, and the maintenance of polio-free status in certified regions until global certification.

Eradication of poliomyelitis in countries affected by conflict

The global initiative to eradicate poliomyelitis is focusing on a small number of countries in Africa (Angola, Democratic Republic of the Congo, Liberia, Sierra Leone, Somalia, Sudan) and Asia (Afghanistan, Tajikistan), where progress has been hindered by armed conflict. In these countries the disintegration of health systems and difficulties of access are major obstacles to the immunization and surveillance strategies necessary for polio eradication. In such circumstances, eradication requires special endeavours, such as the negotiation of ceasefires and truces and the winning of increased direct involvement by communities. Transmission of poliovirus was interrupted during conflicts in Cambodia, Colombia, El Salvador, Peru, the Philippines, and Sri Lanka. Efforts to achieve eradication in areas of conflict have led to extra health benefits: equity in access to immunization, brought about because every child has to be reached; the revitalization and strengthening of routine immunization services through additional externally provided resources; and the establishment of disease surveillance systems. The goal of polio eradication by the end of 2000 remains attainable if supplementary immunization and surveillance can be accelerated in countries affected by conflict.

Poliomyelitis Eradication: Progress, Challenges for the End Game, and Preparation for the Post-Eradication Era

In 1988, the World Health Assembly resolved to eradicate poliomyelitis globally by the year 2000. Dramatic progress toward this goal has occurred: three of the six WHO regions (Region of the Americas, European Region, and Western Pacific Region) are now polio free; and the number of polio-endemic countries decreased from over 125 in 1988 to 30 in 1999. Intensified efforts currently are underway to reach the target as soon as possible after 2000 in the three remaining polio-endemic WHO regions (African Region, Eastern Mediterranean Region, and South-East Asia Region). Even in polio-endemic regions, many countries are already polio free as the geographic extent of poliovirus shrinks while others. especially those experiencing conflict and war, pose substantial challenges to implementing the proven polio eradication strategies. Increasing attention and research now are devoted to the certification of polio eradication in the polio-free regions (that will include the first phase of implementing the Global Plan of Action for the laboratory containment of wild poliovirus) and formulating a policy for stopping all polio vaccination once eradication, containment, and global certification have been achieved. This report outlines the progress toward polio eradication and highlights some of the remaining issues and challenges that must be addressed before polio becomes a disease that future generations know only by history.

Outbreaks of paralytic poliomyelitis during 1996-2012: the changing epidemiology of a disease in the final stages of eradication.

BACKGROUND Despite substantial progress toward eradication of poliomyelitis, the risk of poliomyelitis outbreaks resulting from virus importations into polio-free areas persists. We reviewed the changing epidemiology of outbreaks in the final stages of the eradication initiative. METHODS Available literature on outbreaks of poliomyelitis caused by wild polioviruses between 1996 and 2012 was reviewed. RESULTS During this period, there were 22 outbreaks involving 39 countries. Outbreaks ranged in size from 1 to 1335 cases. These outbreaks caused 4571 cases, representing 21% of all cases reported during this period. Five outbreaks involved multiple countries. In 76% of outbreaks (16/21) with a known age distribution, cases concentrated among children aged <5 years; in 19% (4/21), most cases were among adolescents and adults. The outbreaks among adolescents and adults were associated with higher case-fatality ratios, ranging from 12% in Albania in 1994 to 41% in the Republic of Congo in 2010. The majority of outbreaks were controlled within 6 months with oral poliovirus vaccine. CONCLUSIONS Importations resulting in epidemic transmission of wild poliovirus caused thousands of cases of paralysis often in countries where poliomyelitis had not occurred for many years. The changing epidemiology, with cases and higher case-fatality ratios among adults, increased the severity of these outbreaks.

Using Acute Flaccid Paralysis Surveillance as a Platform for Vaccine-Preventable Disease Surveillance

Abstract Surveillance for acute flaccid paralysis (AFP) is a fundamental cornerstone of the global polio eradication initiative (GPEI). Active surveillance (with visits to health facilities) is a critical strategy of AFP surveillance systems for highly sensitive and timely detection of cases. Because of the extensive resources devoted to AFP surveillance, multiple opportunities exist for additional diseases to be added using GPEI assets, particularly because there is generally 1 district officer responsible for all disease surveillance. For this reason, integrated surveillance has become a standard practice in many countries, ranging from adding surveillance for measles and rubella to integrated disease surveillance for outbreak-prone diseases (integrated disease surveillance and response). This report outlines the current level of disease surveillance integration in 3 countries (Nepal, India, and Nigeria) and proposes that resources continue for long-term maintenance in resource-poor countries of AFP surveillance as a platform for surveillance of vaccine-preventable diseases and other outbreak-prone diseases.

Global control of infectious diseases by vaccination programs

In both industrialized and developing countries, childhood immunization has become one of the most important and cost-effective public health interventions. National immunization programs have prevented millions of deaths since WHO initiated the ‘Expanded Program on Immunization’ in 1974. Smallpox was eradicated in 1979, poliomyelitis is on the verge of eradication, and two thirds of developing countries have eliminated neonatal tetanus. Global immunization coverage was at 78% in 2005. Through their impact on childhood morbidity and mortality, immunization programs are contributing to reaching the ‘Millennium Development Goal 4’ — a two-thirds reduction of under-five mortality by 2015. However, the failure to reach more than 20% of the world’s children with existing vaccines was responsible for at least 2.5 million of an estimated 10.5 million deaths of children under 5 years, mainly in developing countries. Of these deaths, 1.4 million could have been prevented by vaccines currently recommended by WHO. Rapid progress in our understanding of the pathogenesis of infectious diseases, immunology, and biotechnology has increased the number of candidate vaccine antigens available. Pressures are growing on public health decision makers to establish evidence-based ways to decide which new vaccines should be introduced on a large scale into national immunization programs. The gap in access to new vaccines between the developing and industrialized worlds is still wide, and wealthy countries are still the first to introduce and use new vaccines. Interest from countries and partner agencies in vaccination, as one of the most cost-effective public health interventions, continues to be strong, also due to rapid progress in biotechnology and vaccine development and the emergence of global infectious disease threats, including HIV/AIDS, SARS, and influenza. The establishment of the Global Alliance for Vaccines and Immunization has focused global activities to support vaccination programs through raising considerable funds, and to assist especially poorer countries in improving and expanding their vaccination programs. Global efforts concentrate on further reducing the gap in the access to all existing vaccines between industrialized and developing countries.

The critical role of acute flaccid paralysis surveillance in the Global Polio Eradication Initiative

Acute flaccid paralysis (AFP) surveillance is a key strategy used by the Global Polio Eradication Initiative (GPEI) to measure progress towards reaching the global eradication goal. Supported by a global polio laboratory network, AFP surveillance is conducted in 179 of 194 WHO member states. Active surveillance visits to priority health facilities are used to assure all children <15 years with AFP are detected, followed by stool specimen collection and testing for poliovirus in WHO-accredited polio laboratories. The quality of AFP surveillance is regularly monitored with standardized surveillance quality indicators. In highest risk countries and areas, the sensitivity of AFP surveillance is enhanced by environmental surveillance (testing of sewage samples). Genetic sequencing of detected poliovirus isolates yields programmatically important information on polio transmission pathways. AFP surveillance is one of the most valuable assets of the GPEI, with the potential to serve as a platform to build integrated disease surveillance systems. Continued support to maintain AFP surveillance systems will be essential, to reliably monitor the completion of global polio eradication, and to assure that a key resource for building surveillance capacity is transitioned post-eradication to support other health priorities.

Detecting Guillain-Barré syndrome caused by Zika virus using systems developed for polio surveillance

Zika virus disease is caused by a ribonucleic acid (RNA) virus, which is transmitted to humans by mosquitoes of the Aedes aegypti species. Around 80% of infections are asymptomatic. (1) Symptomatic infections are characterized by mild fever lasting from four to seven days, associated with maculopapular rash, arthralgia, conjunctivitis, muscle pain and headache. Until recently, Zika virus disease has never been associated with deaths, intrauterine infections, or congenital anomalies. In 2013 and 2014, during an outbreak in French Polynesia, the disease was linked with GuillainBarre syndrome. (2) Zika infection can be established by detection of Zika virus RNA or specific viral antigens in human clinical samples. It is suspected that over 40 countries had autochthonous Zika virus transmission in 2015 and early 2016. (3,4) In some countries, there is a temporal association of Zika virus infections with severe clinical manifestations, particularly Guillain-Barre syndrome and congenital neurological malformations. (3,4) In December 2015, officials from the Brazilian Ministry of Health reported 76 patients diagnosed with neurological syndromes, of whom 42 (55%) were confirmed as having Guillain-Barre syndrome. (4) Similarly, between December 2015 and January 2016, Salvadorian health officials reported 46 patients with Guillain-Barre syndrome, more than 50% of whom had febrile illness lasting between seven to 15 days before onset of the syndrome. (4) A case-control study conducted in 2013 and 2014 in French Polynesia has shown evidence of Zika virus infections causing Guillain-Barre syndrome. (2) The French Polynesia study found, in most of the patients, neurological symptoms following Zika virus infections lasted a median of six days. (2) With increasing evidence of linkages between Guillain-Barre syndrome and Zika virus infection, (2-4) it is imperative to enhance Guillain-Barre syndrome surveillance. This can be done using existing surveillance systems like the one for acute flaccid paralysis (AFP) used by polio eradication programmes. (5) Scientists warn that in view of outbreaks that occurred in Africa, south-east Asia, the Pacific Islands, and the Americas, the disease now has pandemic potential. (6) In February 2016, the World Health Organization (WHO) declared that the reported clusters of microcephaly and other neurological disorders from the WHO Region of the Americas constituted a Public Health Emergency of International Concern and recommended to enhance surveillance for Zika virus infection. (7) The Aedes species of mosquitoes that transmits the Zika virus and other infections like dengue, chikungunya and yellow fever exists worldwide, posing a high risk for global transmission. (6) A 2016 modelling study looking at the potential for Zika virus spread predicted substantial international spread by travellers from Brazil to the rest of the world. (8) Many cases of microcephaly and Guillain-Barre syndrome are now being reported from countries affected by Zika. (2,4) Surveillance for timely detection and monitoring of Zika infection and screening for microcephaly and Guillain-Barre syndrome will be essential to guide the public health response. Governments and other stakeholders use existing AFP surveillance systems in countries to monitor progress towards a global polio eradication goal. (9) Currently, 91% (177 out of 194) of WHO Member States conduct AFP surveillance. Reporting of AFP in children younger than 15 years is followed by laboratory diagnosis of stool specimens to either confirm polio or identify nonpolio AFP cases. Guillain-Barre syndrome cases are classified as non-polio AFP cases. Guillain-Barre syndrome is the most common non-polio cause for AFP. Most countries achieve or surpass the global standard of an annual rate of at least one case of non-polio AFP per 100000 population of children younger than 15 years. In 2015, globally, 99 582 AFP cases among children younger than 15 years, including 72 laboratory-confirmed wild poliovirus cases, were reported. …

Lessons Learned and Legacy of the Stop Transmission of Polio Program

Abstract In 1988, the by the World Health Assembly established the Global Polio Eradication Initiative, which consisted of a partnership among the World Health Organization (WHO), Rotary International, the Centers for Disease Control and Prevention (CDC), and the United Nations Children’s Fund. By 2016, the annual incidence of polio had decreased by >99.9%, compared with 1988, and at the time of writing, only 3 countries in which wild poliovirus circulation has never been interrupted remain: Afghanistan, Nigeria, and Pakistan. A key strategy for polio eradication has been the development of a skilled and deployable workforce to implement eradication activities across the globe. In 1999, the Stop Transmission of Polio (STOP) program was developed and initiated by the CDC, in collaboration with the WHO, to train and mobilize additional human resources to provide technical assistance to polio-endemic countries. STOP has also informed the development of other public health workforce capacity to support polio eradication efforts, including national STOP programs. In addition, the program has diversified to address measles and rubella elimination, data management and quality, and strengthening routine immunization programs. This article describes the STOP program and how it has contributed to polio eradication by building global public health workforce capacity.

National, Regional and Global Certification Bodies for Polio Eradication: A Framework for Verifying Measles Elimination

Abstract The Global Certification Commission (GCC), Regional Certification Commissions (RCCs), and National Certification Committees (NCCs) provide a framework of independent bodies to assist the Global Polio Eradication Initiative (GPEI) in certifying and maintaining polio eradication in a standardized, ongoing, and credible manner. Their members meet regularly to comprehensively review population immunity, surveillance, laboratory, and other data to assess polio status in the country (NCC), World Health Organization (WHO) region (RCC), or globally (GCC). These highly visible bodies provide a framework to be replicated to independently verify measles and rubella elimination in the regions and globally.