Wild Poliovirus Outbreak Research Articles

Progresses Toward Polio Eradication in Asian Countries: Its History and Japan's Contributions.

Japan experienced a large outbreak of wild poliovirus in the 1960s. The government made an exceptional decision to import oral polio vaccines (OPVs) from the Soviet Union and Canada while bypassing the usual approval process for medical products. Mass vaccination and subsequent, routine immunization successfully contained the wild poliovirus; the last case in Japan was reported in 1980. Domestic OPV had been used to sustain Japan's polio-free state. In 2012, the world's first inactivated polio vaccine developed from the Sabin vaccine replaced OPVs. Domestic vaccines combined with Sabin-derived inactivated polio vaccine are currently used in Japan. When the World Health Assembly announced the Global Polio Eradication Initiative in 1988, the Japanese government made a commitment to support endemic countries. The Japan International Cooperation Agency supported the establishment of microbiological laboratories, surveillance, distribution of polio vaccines and capacity building. Vaccine-derived poliovirus emerged as a new, international risk in the early 2000s. Vaccine-derived poliovirus was also detected in several Asian countries and required an outbreak response with additional vaccinations and strengthened surveillance. Genetically stable, novel, oral polio vaccine type 2 became available for use in outbreak responses and was used in Indonesia. Japan maintains its commitment to work toward the eradication of the poliovirus.

Preventing Importation of Poliovirus in the Horn of Africa: The Success of the Cross-Border Health Initiative in Kenya and Somalia.

.In 2013, the outbreak of wild poliovirus (WPV) in the Horn of Africa (HOA) triggered an aggressive, coordinated national and regional response to interrupt continued transmission. Kenya, Somalia, Ethiopia, South Sudan, and other HOA countries share a range of complex factors that enabled the outbreak: porous and sparsely populated borders, insecurity due to armed conflicts, and weak health systems with persistently under-resourced health facilities resulting in low-quality care and low levels of immunization coverage in mobile populations. Consequently, the continued risk of WPV importation demanded cross-border and intersectoral collaboration. Assessing and addressing persistent communication gaps at the subnational levels were necessary to gain traction for improved immunization coverage and surveillance activities. This article describes a systematic approach to institutionalizing processes of dialogue and facilitation that can provide for a sustainable and effective joint cross-border health platform between Kenya and Somalia. It examines an operational model called the Cross-Border Health Initiative (CBHI) to support joint intercountry collaboration and coordination efforts. To evaluate progress of the CBHI, the authors used data from population coverage surveys for routine immunization and supplemental immunization activities (for polio), from acute flaccid paralysis (AFP) surveillance, and from plans developed by border districts and border health facilities. The project-trained community health volunteers have been a critical link between the hard-to-reach communities and the health facilities as well as an excellent resource to support understaffed health facilities. The authors conclude that the CBHI has been effective in bolstering immunization coverage, disease surveillance, and rapid outbreak response in border areas. The CBHI has the potential to address other public health threats that transcend borders.

Contributions of Volunteer Community Mobilizers to Polio Eradication in Nigeria: The Experiences of Non-governmental and Civil Society Organizations.

.The Northern states were the epicenter of the wild poliovirus outbreak in Nigeria in 2016. To raise immunization coverage, particularly of polio, the Polio Eradication Initiative (PEI) in Nigeria introduced the use of nongovernmental organizations and volunteer community mobilizers (VCMs) through the CORE Group Polio Project (CGPP). The CGPP has been contributing to Nigeria’s polio eradication efforts since 2013. This article explores the contributions of the 2,130 VCMs deployed in 31 participating local government areas in the five implementing CGPP states from 2014 to 2017 to increase awareness, understanding, and acceptance of polio immunization. Data for the study were collected from primary and secondary sources using five collection methods: a survey of VCM supervisors, focus group discussions with VCMs and their supervisors, key in-depth interviews with community stakeholders, case studies of specific best practices of VCMs, and a review of documents and records. A review of the data shows that the VCMs received comprehensive training on the importance of the PEI, routine immunization, Acute Flaccid Paralysis (AFP) surveillance, social mobilization and community engagement, use of behavior change communication tools, and interpersonal communication skills. According to the data collected, the VCMs used the following innovative strategies to ensure high vaccination coverage: house-to-house mobilization, community dialogues, compound meetings, community health camps, and tracking of non-compliant families, missed children, and dropouts. The involvement of VCMs in Nigeria’s PEI efforts has been a pivotal contribution to reductions in the number of households rejecting polio immunization, the proportion of families with missed children, the proportion of families that were non-compliant, and the number of polio cases.

Immunogenicity of Oral Polio Vaccine and Salk Inactive Polio Vaccine Against Xinjiang Imported Type 1 Wild Poliovirus.

An outbreak of an imported Type 1 wild poliovirus from Pakistan occurred in the Xinjiang Uygur Autonomous Region of China in 2011, although the local immunity status of the oral polio vaccine (OPV) was relatively satisfied. Neutralizing antibody titers against the Xinjiang strain and Sabin 1 strain were measured in 237 sera from 3 groups of fully OPV-vaccinated persons and 1 group of infants fully vaccinated with the inactive polio vaccine (IPV). Additionally, 17 sera collected from 1 Xinjiang poliomyelitis case and his 16 contacts were also tested. Genomic sequencing was conducted the Xinjiang strain. The antibody titers against the Xinjiang strain in each of 237 sera were significantly lower than those against the Sabin 1 strain. Notably, 40.0% of children in Group 1 were seronegative against the Xinjiang strain, which indicated that they might play an important role in wild poliovirus transmission, although their antibody titers against the Sabin 1 strain varied between 1:8 and 1:512. Meanwhile, serological results of the Xinjiang poliomyelitis case and his contacts also provided evidence that a proportion of OPV-vaccinated children had indeed been involved in the transmission chain of the Xinjiang outbreak. Genomic sequencing indicated that the Xinjiang strain was greatly distinguishable from the Sabin 1 strain in neutralizing antigenic sites. The lack of neutralizing antibodies against the Xinjiang strain in persons vaccinated by OPV may be associated with the transmission of Type 1 wild poliovirus in Xinjiang. Using Salk IPV along with OPV might be considered in a wild poliovirus outbreak response, especially in the countries which continued to have persistent wild poliovirus circulation.

A descriptive characterization of acute flaccid paralysis in Nigeria, 2015

Introduction: World Health Organization defines Acute Flaccid Paralysis (AFP) as a syndrome characterized by sudden and rapid weakness of the extremities. The outbreak of wild polio virus in Borno State in August, 2016, necessitated intensive responses in the northern parts of Nigeria with several Polio Immunization Plus Days activities. This study aimed at descriptively characterization of AFP in Nigeria, with a view of identifying the population at risk of AFP, to assess the health seeking behavior of patients with AFP and to determine the pattern of paralysis.

Modeling the spread of polio in an IPV-vaccinated population: lessons learned from the 2013 silent outbreak in southern Israel.

BackgroundPolio eradication is an extraordinary globally coordinated health program in terms of its magnitude and reach, leading to the elimination of wild poliovirus (WPV) in most parts of the world. In 2013, a silent outbreak of WPV was detected in Israel, a country using an inactivated polio vaccine (IPV) exclusively since 2005. The outbreak was detected using environmental surveillance (ES) of sewage reservoirs. Stool surveys indicated the outbreak to be restricted mainly to children under the age of 10 in the Bedouin population of southern Israel. In order to curtail the outbreak, a nationwide vaccination campaign using oral polio vaccine (OPV) was conducted, targeting all children under 10.MethodsA transmission model, fitted to the results of the stool surveys, with additional conditions set by the ES measurements, was used to evaluate the prevalence of WPV in Bedouin children and the effectiveness of the vaccination campaign. Employing the parameter estimates of the model fitting, the model was used to investigate the effect of alternative timings, coverages and dosages of the OPV campaign on the outcome of the outbreak.ResultsThe mean estimate for the mean reproductive number was 1.77 (95 % credible interval, 1.46–2.30). With seasonal variation, the reproductive number maximum range was between zero and six. The mean estimate for the mean infectious periods was 16.8 (8.6–24.9) days. The modeling indicates the OPV campaign was effective in curtailing the outbreak. The mean estimate for the attack rate in Bedouin children under 10 at the end of 2014 was 42 % (22–65 %), whereas without the campaign the mean projected attack rate was 57 % (35–74 %). The campaign also likely shortened the duration of the outbreak by a mean estimate of 309 (2–846) days. A faster initiation of the OPV campaign could have reduced the incidence of WPV even if a lower coverage was reached, at the risk of prolonging the outbreak.ConclusionsOPV campaigns are essential for interrupting WPV transmission, even in a developed country setting with a high coverage of IPV. In this setting, establishing ES of WPV circulation is particularly crucial for early detection and containment of an outbreak.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-016-0637-z) contains supplementary material, which is available to authorized users.

Recommended Strategies to Move Closer Toward the Global Eradication of Polio: International Health Regulations.

DEAR EDITOR, Polio was once considered a fearsome disease with a tendency to strike suddenly and paralyze millions of children for their entire lifetime.[1] However, in response to the Global Polio Eradication Initiative, assistance from the World Health Organization, and support from various stakeholders (viz., policy makers, health personnel, nongovernmental organizations, etc.), the number of polio cases have been reduced by more than 99% when compared with 1998 estimates.[2] However, there is a definitive potential risk of spread of polio from these nations to other nations that have less than adequate vaccination.[1,2,3] Unlike most other infectious diseases, polio can be completely eradicated as none of the three strains of wild poliovirus can survive outside the human body for longer durations and will die, if they cannot infect a susceptible individual.[4] Further, type 2 wild poliovirus has already been eradicated in the year 1999 while very few cases attributed to type 3 wild poliovirus have been reported in the recent years.[1,4] In fact, other than Nigeria (in which last wild polio case was detected 1 year back), only two countries—Pakistan and Afghanistan—are remaining where polio transmission has never been interrupted.[2,3] Most of these improvements and reduction in the incidence of polio cases on the global platform has been observed following the declaration of polio as a Public Health Emergency of International Concern.[1,2] Even though in 2015, less than a third of the number of cases have been reported in Pakistan (in contrast to the number of cases in the similar interval in 2014) with no exportation of wild poliovirus cases since October 2014 and a significant decline in the number of unimmunized children, still Pakistan alone accounts for almost 85% of all global wild poliovirus cases in the current year.[2] On the contrary, Afghanistan has reported international spread of wild poliovirus even in 2015 (viz., two cases to Quetta and Sindh regions of Pakistan).[2] This is mainly because of the weak public health systems, noncompliance with the International Health Regulations (IHR) recommendations for the international air travelers (viz., measures not implemented uniformly for all ages, no tracking of the vaccination status of travellers, no exit screening or restriction on unvaccinated travellers, etc.), sharing of a common zone of poliovirus transmission between the two nations, suspension of mass vaccination campaigns in the Kandahar region, and poor sanitation facilities.[1,2] In an attempt to expedite the process of global eradication of polio and to address the existing deficient mechanisms, a wide range of recommendations has been proposed by the IHR emergency committee.[2] These recommendations have been broadly divided into three major categories, namely states currently exporting wild poliovirus (Pakistan and Afghanistan); states infected with wild poliovirus, but not currently exporting (Nigeria and Somalia); and states no longer infected by wild poliovirus, but which remain vulnerable to international spread (Ethiopia, Syria, etc.).[2] For the first two categories of nations, it has been advocated that these should declare interruption of poliovirus transmission as a national public health emergency; administer to all residents or long-term visitors (more than 4 weeks), a dose of oral poliovirus vaccine (OPV) or inactivated poliovirus vaccine (IPV) between 4 weeks and 1 year prior to international travel; ensure receiving of OPV/IPV to even urgent travelers; provision of an international certificate of vaccination or prophylaxis to the travelers; restrict departure of travelers who lack the necessary documents at the point of departure; improve level of coordination at various levels to strengthen cross-border efforts; sustain these measures until at least 6 months have passed without new exportations; and provide monthly (currently exporting) or once in a year (not currently exporting) report to IHR about the implementation of recommendations.[2,5] However, the nations that are no longer infected by wild poliovirus but are still vulnerable to international spread should strengthen their routine vaccination and surveillance mechanism, especially among the mobile and vulnerable populations; enhance the level of cooperation and cross-border coordination to enable prompt detection of wild poliovirus and vaccination of high-risk population groups; and provide a comprehensive report every year regarding prevention and control measures.[2,6] In addition, implementation of cost-effective measures to neutralize the existing insecurity and inaccessibility to the healthcare services, especially in the conflict-affected nations can also prevent a major outbreak of wild poliovirus.[4,5,6] To conclude, a critical end stage has been achieved by the world for global polio eradication and any form of ignorance can either reverse or even prevent the world from achieving this goal. Thus, it is high time that both affected nations and even other nations continue to work according to the laid recommendations so that polio eradication can be achieved.

Evidence-Based Engagement of the Somali Pastoralists of the Horn of Africa in Polio Immunization: Overview of Tracking, Cross-Border, Operations, and Communication Strategies

Building on the experience of the 2013–2014 wild poliovirus outbreak in the Horn of Africa, this study examines applied strategies that helped to engage pastoralists of the Somali cluster (Somalia, Somali Region of Ethiopia, and North-East Kenya) in supplementary immunization activities. Aimed at being applicable to other public health interventions, the study synthesizes knowledge about Somali pastoralism in the Horn of Africa and explains the approaches used for tracking nomadic groups and creating dialogue, as well as building trust to enable better vaccination opportunities for pastoralist children. Interventions across the three countries included creating a network of informants and influencers, engagement with clan leaders, mapping of water points and livestock markets, forming a partnership with an animal vaccination program, cross-border coordination, and establishment of permanent transit vaccination points. The proportion of children who had never been vaccinated against polio in the overall in...

Stool screening of Syrian refugees and asylum seekers in Germany, 2013/2014: Identification of Sabin like polioviruses

Germany is a partner of the Global Polio Eradication Initiative. Assurance of polio free status is based on enterovirus surveillance, which focuses on patients with signs of acute flaccid paralysis or aseptic meningitis/encephalitis, representing the key symptoms of poliovirus infection. In response to the wild poliovirus outbreak in Syria 2013 and high number of refugees coming from Syria to Germany, stool samples from 629 Syrian refugees/asylum seekers aged <3 years were screened for wild poliovirus between November 2013 and April 2014. Ninety-three samples (14.8%) were positive in an enterovirus specific PCR. Of these, 12 contained Sabin-like polioviruses. The remaining 81 samples were characterized as non-polio enteroviruses representing several members of groups A–C as well as rhinovirus. Wild-type poliovirus was not detected via stool screening involving molecular and virological methods, indicating a very low risk for the importation by Syrian refugees and asylum seekers at that time.

Public Health Emergency of International Concern (PHEIC) has Declared Twice in 2014; Polio and Ebola at the Top.

BackgroundThe current Ebola outbreak in West Africa and the large scale wild Polio virus outbreak in several countries are the top most issues among international public health and scientific communities' debates and concerns. These two outbreaks were judged to be declared as Public Health Emergency of International Concern (PHEIC) during 2014. This is the first time ever to have such circumstance of two PHEICs at the same time.DiscussionPHEIC, which has to be declared by WHO Director General after a recommendation of IHR Emergency Committee; is observed to start in countries with fragile health system and conflict areas. Then it rapidly spread to threaten the global public health. The year 2014 has uniquely witnessed declaration of two events as PHEIC according to IHR (2005); Polio and Ebola Virus Disease (EVD). Both outbreaks are caused by viruses such as H1N1 which was previously declared as PHEIC in 2009.SummaryPublic Health Emergencies of International Concern in 2014 occurred in countries with weak health systems and conflicts and threatening the whole globe. International collaborative work is required to contain the event and to mobilize resources/capacities between countries. Moreover, public health surveillance systems as core capacity for IHR (2005) should be strengthened in all countries with focus on those with limited capacity and ongoing conflicts. The ultimate aim is timely detection of potential PHEIC events in the future along with early preparedness and response plans.

Enhanced surveillance of acute flaccid paralysis following importation of wild poliovirus in Xinjiang Uygur Autonomous Region, China

BackgroundAfter being polio free for more than 10 years, an outbreak occurred in China in 2011 in Xinjiang Uygur Autonomous Region (Xinjiang) following the importation of wild poliovirus (WPV) originating from neighboring Pakistan.MethodsTo strengthen acute flaccid paralysis (AFP) surveillance in Xinjiang, “zero case daily reporting” and retrospective searching of AFP cases were initiated after the confirmation of the WPV outbreak. To pinpoint all the polio cases in time, AFP surveillance system was expanded to include persons of all ages in the entire population in Xinjiang.ResultsTotally, 578 AFP cases were reported in 2011 in Xinjiang, including 21 WPV cases, 23 clinical compatible polio cases and 534 non-polio AFP cases. Of the 44 polio cases, 27 (61.4%) cases were reported among adults aged 15–53 years. Strengthening AFP surveillance resulted in an increase in the number of non-polio AFP cases in 2011 (148 children < 15 years) compared with 76 cases < 15 years in 2010. The AFP surveillance system in Xinjiang was sensitive enough to detect polio cases, with the AFP incidence of 3.28/100,000 among children < 15 years of age.ConclusionsIncorporating adult cases into the AFP surveillance system is of potential value to understand the overall characteristics of the epidemic and to guide emergency responses, especially in countries facing WPV outbreak following long-term polio free status. The AFP surveillance system in Xinjiang was satisfactory despite limitations in biological sample collection.

Infectious disease surveillance update

An outbreak of wild poliovirus in the Horn of Africa has cause 174 cases in Somalia, 14 in Kenya, and three in Ethiopia. As of Oct 1, 2013, three more suspected cases have been repoted in South Sudan. The patients suspected to have the disease are from North Bahr El Gazal state (close to the border to Sudan) and Eastern Equatoria state (close to the border with Kenya and Uganda). The samples are awaiting confirmation by genetic sequencing. An emergency outbreak response is being organised, including an immediate supplementary immunisation activity in and around the affected regions.

An Outbreak of Wild Poliovirus in the Republic of Congo, 2010-2011

The Republic of Congo has had no cases of wild poliovirus type 1 (WPV1) since 2000. In October 2010, a neurologist noted an abnormal number of cases of acute flaccid paralysis (AFP) among adults, which were later confirmed to be caused by WPV1. Those presenting with AFP underwent clinical history, physical examination, and clinical specimen collection to determine if they had polio. AFP cases were classified as laboratory-confirmed, clinical, or nonpolio AFP. Epidemiologic features of the outbreak were analyzed. From 19 September 2010 to 22 January 2011, 445 cases of WPV1 were reported in the Republic of Congo; 390 cases were from Pointe Noire. Overall, 331 cases were among adults; 378 cases were clinically confirmed, and 64 cases were laboratory confirmed. The case-fatality ratio (CFR) was 43%. Epidemiologic characteristics differed among polio cases reported in Pointe Noire and cases reported in the rest of the Republic of Congo, including age distribution and CFR. The outbreak stopped after multiple vaccination rounds with oral poliovirus vaccine, which targeted the entire population. This outbreak underscores the need to maintain high vaccination coverage to prevent outbreaks, the need to maintain timely high-quality surveillance to rapidly identify and respond to any potential cases before an outbreak escalates, and the need to perform ongoing risk assessments of immunity gaps in polio-free countries.