Last data update: Jan 27, 2025. (Total: 48650 publications since 2009)
Records 1-30 (of 31 Records) |
Query Trace: Jafari H[original query] |
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A systematic review of the data, methods and environmental covariates used to map Aedes-borne arbovirus transmission risk
Lim AY , Jafari Y , Caldwell JM , Clapham HE , Gaythorpe KAM , Hussain-Alkhateeb L , Johansson MA , Kraemer MUG , Maude RJ , McCormack CP , Messina JP , Mordecai EA , Rabe IB , Reiner RC Jr , Ryan SJ , Salje H , Semenza JC , Rojas DP , Brady OJ . BMC Infect Dis 2023 23 (1) 708 ![]() BACKGROUND: Aedes (Stegomyia)-borne diseases are an expanding global threat, but gaps in surveillance make comprehensive and comparable risk assessments challenging. Geostatistical models combine data from multiple locations and use links with environmental and socioeconomic factors to make predictive risk maps. Here we systematically review past approaches to map risk for different Aedes-borne arboviruses from local to global scales, identifying differences and similarities in the data types, covariates, and modelling approaches used. METHODS: We searched on-line databases for predictive risk mapping studies for dengue, Zika, chikungunya, and yellow fever with no geographical or date restrictions. We included studies that needed to parameterise or fit their model to real-world epidemiological data and make predictions to new spatial locations of some measure of population-level risk of viral transmission (e.g. incidence, occurrence, suitability, etc.). RESULTS: We found a growing number of arbovirus risk mapping studies across all endemic regions and arboviral diseases, with a total of 176 papers published 2002-2022 with the largest increases shortly following major epidemics. Three dominant use cases emerged: (i) global maps to identify limits of transmission, estimate burden and assess impacts of future global change, (ii) regional models used to predict the spread of major epidemics between countries and (iii) national and sub-national models that use local datasets to better understand transmission dynamics to improve outbreak detection and response. Temperature and rainfall were the most popular choice of covariates (included in 50% and 40% of studies respectively) but variables such as human mobility are increasingly being included. Surprisingly, few studies (22%, 31/144) robustly tested combinations of covariates from different domains (e.g. climatic, sociodemographic, ecological, etc.) and only 49% of studies assessed predictive performance via out-of-sample validation procedures. CONCLUSIONS: Here we show that approaches to map risk for different arboviruses have diversified in response to changing use cases, epidemiology and data availability. We identify key differences in mapping approaches between different arboviral diseases, discuss future research needs and outline specific recommendations for future arbovirus mapping. |
Progress toward poliomyelitis eradication - Pakistan, January 2022-June 2023
Mbaeyi C , Baig S , Safdar RM , Khan Z , Young H , Jorba J , Wadood ZM , Jafari H , Alam MM , Franka R . MMWR Morb Mortal Wkly Rep 2023 72 (33) 880-885 Since the establishment of the Global Polio Eradication Initiative in 1988, Pakistan remains one of only two countries (along with Afghanistan) with continued endemic transmission of wild poliovirus (WPV). This report describes Pakistan's progress toward polio eradication during January 2022-June 2023. During 2022, Pakistan reported 20 WPV type 1 (WPV1) cases, all of which occurred within a small geographic area encompassing three districts in south Khyber Pakhtunkhwa. As of June 23, only a single WPV1 case from Bannu district in Khyber Pakhtunkhwa province has been reported in 2023, compared with 13 cases during the same period in 2022. In addition, 11 WPV1 isolates have been reported from various environmental surveillance (ES) sewage sampling sites to date in 2023, including in Karachi, the capital of the southern province of Sindh. Substantial gaps remain in the quality of supplementary immunization activities (SIAs), especially in poliovirus reservoir areas. Despite the attenuation and apparently limited geographic scope of poliovirus circulation in Pakistan, the isolation of WPV1 from an ES site in Karachi is cause for concern about the actual geographic limits of transmission. Interrupting WPV1 transmission will require meticulous tracking and sustained innovative efforts to vaccinate children who are regularly missed during SIAs and rapidly responding to any new WPV1 isolations. |
A systematic review of the data, methods and environmental covariates used to map Aedes-borne arbovirus transmission risk (preprint)
Lim AY , Jafari Y , Caldwell JM , Clapham HE , Gaythorpe KAM , Hussain-Alkhateeb L , Johansson MA , Kraemer MUG , Maude RJ , McCormack CP , Messina JP , Mordecai EA , Rabe IB , Reiner RC , Ryan SJ , Salje H , Semenza JC , Rojas DP , Brady OJ . medRxiv 2023 20 Background Aedes (Stegomyia)-borne diseases are an expanding global threat, but gaps in surveillance make comprehensive and comparable risk assessments challenging. Geostatistical models combine data from multiple locations and use links with environmental and socioeconomic factors to make predictive risk maps. Here we systematically review past approaches to map risk for different Aedesborne arboviruses from local to global scales, identifying differences and similarities in the data types, covariates, and modelling approaches used. Methods We searched on-line databases for predictive risk mapping studies for dengue, Zika, chikungunya, and yellow fever with no geographical or date restrictions. We included studies that needed to parameterise or fit their model to real-world epidemiological data and make predictions to new spatial locations of some measure of population-level risk of viral transmission (e.g. incidence, occurrence, suitability, etc). Results We found a growing number of arbovirus risk mapping studies across all endemic regions and arboviral diseases, with a total of 183 papers published 2002-2022 with the largest increases shortly following major epidemics. Three dominant use cases emerged: i) global maps to identify limits of transmission, estimate burden and assess impacts of future global change, ii) regional models used to predict the spread of major epidemics between countries and iii) national and sub-national models that use local datasets to better understand transmission dynamics to improve outbreak detection and response. Temperature and rainfall were the most popular choice of covariates (included in 50% and 40% of studies respectively) but variables such as human mobility are increasingly being included. Surprisingly, few studies (22%, 33/148) robustly tested combinations of covariates from different domains (e.g. climatic, sociodemographic, ecological, etc) and only 48% of studies assessed predictive performance via out-of-sample validation procedures. Conclusions Here we show that approaches to map risk for different arboviruses have diversified in response to changing use cases, epidemiology and data availability. We outline specific recommendations for future studies regarding aims and data choice, covariate selection, model formulation and evaluation. Copyright The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license. |
Progress toward poliomyelitis eradication - Pakistan, January 2021-July 2022
Mbaeyi C , Baig S , Safdar MR , Khan Z , Young H , Jorba J , Wadood ZM , Jafari H , Alam MM , Franka R . MMWR Morb Mortal Wkly Rep 2022 71 (42) 1313-1318 After reporting a single wild poliovirus (WPV) type 1 (WPV1) case in 2021, Pakistan reported 14 cases during April 1-July 31, 2022. Pakistan and Afghanistan are the only countries where endemic WPV transmission has never been interrupted (1). In its current 5-year strategic plan, the Global Polio Eradication Initiative (GPEI) has set a goal of interrupting all WPV1 transmission by the end of 2023 (1-3). The reemergence of WPV cases in Pakistan after 14 months with no case detection has uncovered transmission in southern Khyber Pakhtunkhwa province, the most historically challenging area. This report describes Pakistan's progress toward polio eradication during January 2021-July 2022 and updates previous reports (4,5). As of August 20, 2022, all but one of the 14 WPV1 cases in Pakistan during 2022 have been reported from North Waziristan district in Khyber Pakhtunkhwa. In underimmunized populations, excretion of vaccine virus can, during a period of 12-18 months, lead to reversion to neurovirulence, resulting in circulating vaccine-derived polioviruses (cVDPVs), which can cause paralysis and outbreaks. An outbreak of cVDPV type 2 (cVDPV2), which began in Pakistan in 2019, has been successfully contained; the last case occurred in April 2021 (1,6). Despite program improvements, 400,000-500,000 children continue to be missed during nationwide polio supplementary immunization activities (SIAs),* and recent isolation of poliovirus from sewage samples collected in other provinces suggests wider WPV1 circulation during the ongoing high transmission season. Although vaccination efforts have been recently complicated by months of flooding during the summer of 2022, to successfully interrupt WPV1 transmission in the core reservoirs in southern Khyber Pakhtunkhwa and reach the GPEI goal, emphasis should be placed on further improving microplanning and supervision of SIAs and on systematic tracking and vaccination of persistently missed children in these reservoir areas of Pakistan. |
Rethinking public health campaigns in the COVID-19 era: a call to improve effectiveness, equity and impact
Jafari H , Saarlas KN , Schluter WW , Espinal M , Ijaz K , Gregory C , Filler S , Wolff C , Krause LK , O'Brien K , Pearson L , Gupta A , Rebollo Polo M , Shuaib F . BMJ Glob Health 2021 6 (11) Health campaigns are time-bound, intermittent activities that address specific epidemiological challenges, expediently fill delivery gaps or provide surge coverage for health interventions. | They can be used to prevent or respond to disease outbreaks, control or eliminate targeted diseases as a public health problem, eradicate a disease altogether or achieve other health goals. | In 2020, more than 530 health campaigns were planned for 26 different interventions representing 13 diseases and 105 countries. | Due to the COVID-19 pandemic, by the end of last year, about half of planned campaigns were postponed, cancelled, or suspended leaving hundreds of millions of children and families at risk of vaccine-preventable diseases, tropical diseases and malnutrition. | So far in 2021, more than 280 campaigns have been cancelled or delayed. | As health campaigns restart and catch up on the delivery of missed drugs, vaccines and nutritional supplements, and countries roll out COVID-19 vaccines, there is an opportunity to rethink the way we plan and implement campaigns to improve their effectiveness and impact. | |
Progress toward poliomyelitis eradication - Pakistan, January 2020-July 2021
Mbaeyi C , Baig S , Khan Z , Young H , Kader M , Jorba J , Safdar MR , Jafari H , Franka R . MMWR Morb Mortal Wkly Rep 2021 70 (39) 1359-1364 When the Global Polio Eradication Initiative began in 1988, wild poliovirus (WPV) transmission was occurring in 125 countries; currently, only WPV type 1 (WPV1) transmission continues, and as of August 2021, WPV1 transmission persists in only two countries (1,2). This report describes Pakistan's progress toward polio eradication during January 2020-July 2021 and updates previous reports (3,4). In 2020, Pakistan reported 84 WPV1 cases, a 43% reduction from 2019; as of August 25, 2021, Pakistan has reported one WPV1 case in 2021. Circulating vaccine-derived poliovirus (cVDPV) emerges as a result of attenuated oral poliovirus vaccine (OPV) virus regaining neurovirulence after prolonged circulation in underimmunized populations and can lead to paralysis. In 2019, 22 cases of cVDPV type 2 (cVDPV2) were reported in Pakistan, 135 cases were reported in 2020, and eight cases have been reported as of August 25, 2021. Because of the COVID-19 pandemic, planned supplementary immunization activities (SIAs)* were suspended during mid-March-June 2020 (3,5). Seven SIAs were implemented during July 2020-July 2021 without substantial decreases in SIA quality. Improving the quality of polio SIAs, vaccinating immigrants from Afghanistan, and implementing changes to enhance program accountability and performance would help the Pakistan polio program achieve its goal of interrupting WPV1 transmission by the end of 2022. |
Preventing the cross-border spread of zoonotic diseases: Multisectoral community engagement to characterize animal mobility-Uganda, 2020
Medley AM , Gasanani J , Nyolimati CA , McIntyre E , Ward S , Okuyo B , Kabiito D , Bender C , Jafari Z , LaMorde M , Babigumira PA , Nakiire L , Agwang C , Merrill R , Ndumu D , Doris K . Zoonoses Public Health 2021 68 (7) 747-759 In Uganda, the borders are highly porous to animal movement, which may contribute to zoonotic disease spread. We piloted an animal adaptation of an existing human-focused toolkit to collect data on animal movement patterns and interactions to inform One Health programs. During January 2020, we conducted focus group discussions and key informant interviews with participatory mapping of 2 national-level One Health stakeholders and 2 local-level abattoir representatives from Kampala. Zoonotic disease hotspots changed in 2020 compared with reports from 2017-2019. In contrast to local-level participants, national-level participants highlighted districts rather than specific locations. Everyone discussed livestock species; only national-level participants mentioned wildlife. Participants described seasonality differently. Stakeholders used the results to identify locations for zoonotic disease interventions and sites for future data collection. This implementation of an animal-adapted population mobility mapping exercise highlights the importance of multisectoral initiatives to promote One Health border health approaches. |
Progress toward poliomyelitis eradication - Pakistan, January 2019-September 2020
Hsu CH , Rehman MS , Bullard K , Jorba J , Kader M , Young H , Safdar M , Jafari HS , Ehrhardt D . MMWR Morb Mortal Wkly Rep 2020 69 (46) 1748-1752 Pakistan and Afghanistan are the only countries where wild poliovirus type 1 (WPV1) is endemic (1,2). In 2019, Pakistan reported 147 WPV1 cases, approximately 12 times the number reported in 2018. As of September 15, 72 cases had been reported in 2020. Since 2019, WPV1 transmission has also spread from Pakistan's core poliovirus reservoirs (Karachi, Peshawar, and Quetta block) to southern districts of Khyber Pakhtunkhwa (KP), Punjab, and Sindh provinces. Further, an outbreak of circulating vaccine-derived poliovirus type 2 (cVDPV2), first detected in July 2019, has caused 22 paralytic cases in 2019 and 59 as of September 15, 2020, throughout the country. The coronavirus disease 2019 (COVID-19) pandemic has substantially reduced delivery of polio vaccines through essential immunization (formerly routine immunization) and prevented implementation of polio supplementary immunization activities (SIAs)* during March-July 2020. This report describes Pakistan's progress in polio eradication during January 2019-September 2020 and updates previous reports (1,3,4). The Pakistan polio program has reinitiated SIAs and will need large, intensive, high-quality campaigns with strategic use of available oral poliovirus vaccines (OPVs)(†) to control the surge and widespread transmission of WPV1 and cVDPV2. |
Progress toward poliomyelitis eradication - Pakistan, January 2018-September 2019
Hsu CH , Kader M , Mahamud A , Bullard K , Jorba J , Agbor J , Safi MM , Jafari HS , Ehrhardt D . MMWR Morb Mortal Wkly Rep 2019 68 (45) 1029-1033 Afghanistan and Pakistan are the only countries that continue to confirm ongoing wild poliovirus type 1 (WPV1) transmission (1). During January 2018-September 2019 the number of WPV1 cases in Pakistan increased, compared with the number during the previous 4 years. This report updates previous reports on Pakistan's polio eradication activities, progress, and challenges (2,3). In 2018, Pakistan reported 12 WPV1 cases, a 50% increase from eight cases in 2017, and a 31% increase in the proportion of WPV1-positive sites under environmental surveillance (i.e., sampling of sewage to detect poliovirus). As of November 7, 2019, 80 WPV1 cases had been reported, compared with eight cases by the same time in 2018. An intensive schedule of supplementary immunization activities (SIAs)* implemented by community health workers in the core reservoirs (i.e., Karachi, Peshawar, and Quetta) where WPV1 circulation has never been interrupted, and by mobile teams, has failed to interrupt WPV1 transmission in core reservoirs and prevent WPV1 resurgence in nonreservoir areas. Sewage samples have indicated wide WPV1 transmission in nonreservoir areas in other districts and provinces. Vaccine refusals, chronically missed children, community campaign fatigue, and poor vaccination management and implementation have exacerbated the situation. To overcome challenges to vaccinating children who are chronically missed in SIAs and to attain country and global polio eradication goals, substantial changes are needed in Pakistan's polio eradication program, including continuing cross-border coordination with Afghanistan, gaining community trust, conducting high-quality vaccination campaigns, improving oversight of field activities, and improving managerial processes to unify eradication efforts. |
Development of a costed national action plan for health security in Pakistan: Lessons learned
Safi M , Ijaz K , Samhouri D , Malik M , Sabih F , Kandel N , Salman M , Suryantoro L , Liban A , Jafari H , Hafeez A . Health Secur 2018 16 S25-s29 In order to assess progress toward achieving compliance with the International Health Regulations (2005), member states may voluntarily request a Joint External Evaluation (JEE). Pakistan was the first country in the WHO Eastern Mediterranean Region to volunteer for and complete a JEE to establish the baseline of the country's public health capacity across multiple sectors covering 19 technical areas. It subsequently developed a post-JEE costed National Action Plan for Health Security (NAPHS). The process for developing the costed NAPHS was based on objectives and activities related to the 3 to 5 priority actions for each of the 19 JEE technical areas. Four key lessons were learned during the process of developing the NAPHS. First, multisectoral coordination at both federal and provincial levels is important in a devolved health system, where provinces are autonomous from a public health sector standpoint. Second, the development of a costed NAPHS requires engagement and investment of the country's own resources for sustainability as well as donor coordination among national and international donors and partners. Engagement from the ministries of Finance, Planning and Development, and Foreign Affairs and from WHO was also important. Third, development of predefined goals, targets, and indicators aligned with the JEE as part of the NAPHS process proved to be critical, as they can be used to monitor progress toward implementation of the NAPHS and provide data for repeat JEEs. Lastly, several challenges were identified related to the NAPHS process and costing tool, which need to be addressed by WHO and partners to help countries develop their plans. |
World Health Organization Joint External Evaluations in the Eastern Mediterranean Region, 2016-17
Samhouri D , Ijaz K , Thieren M , Flahault A , Babich SM , Jafari H , Mahjour J . Health Secur 2018 16 (1) 69-76 By 2014, only 33% of countries had self-reported compliance with the International Health Regulations (2005), including 8 countries from the Eastern Mediterranean Region (EMR). During the Ebola epidemic, the discovery of a gap between objective assessment and self-reports for certain IHR capacities prompted the World Health Organization (WHO) to review and update the IHR monitoring and evaluation framework to include a voluntary objective review process, called Joint External Evaluation (JEE), that did not exist before. The regional committee for the EMR approved the JEE and encouraged its 21 member states to volunteer for reviews. Standardized processes and procedures were developed for conducting JEEs. Of the 52 JEEs completed to date globally, 14 (27%) are from the EMR. Three (21%) of 14 member states completing the JEE in the EMR have also worked on a post-JEE national action plan for health security (NAPHS). A survey conducted about the JEE experience from focal points in EMR member states underlined the strengths of the JEE process: its multisectoral and open discussion approach; standardization of the JEE process; WHO's critical role in supporting JEE preparation and conduct; and the need for guidance development for a costed NAPHS. The success of JEEs depends not only on proper preparations and completion of the JEE but also on the development of a country-led, owned, and costed NAPHS and its implementation, including financial commitments along with donor and partners' engagement and coordination. |
US Centers for Disease Control and Prevention and its partners' contributions to global health security
Tappero JW , Cassell CH , Bunnell RE , Angulo FJ , Craig A , Pesik N , Dahl BA , Ijaz K , Jafari H , Martin R . Emerg Infect Dis 2017 23 (13) S5-S14 To achieve compliance with the revised World Health Organization International Health Regulations (IHR 2005), countries must be able to rapidly prevent, detect, and respond to public health threats. Most nations, however, remain unprepared to manage and control complex health emergencies, whether due to natural disasters, emerging infectious disease outbreaks, or the inadvertent or intentional release of highly pathogenic organisms. The US Centers for Disease Control and Prevention (CDC) works with countries and partners to build and strengthen global health security preparedness so they can quickly respond to public health crises. This report highlights selected CDC global health protection platform accomplishments that help mitigate global health threats and build core, cross-cutting capacity to identify and contain disease outbreaks at their source. CDC contributions support country efforts to achieve IHR 2005 compliance, contribute to the international framework for countering infectious disease crises, and enhance health security for Americans and populations around the world. |
Joint External Evaluation - development and scale-up of global multisectoral health capacity evaluation process
Bell E , Tappero JW , Ijaz K , Bartee M , Fernandez J , Burris H , Sliter K , Nikkari S , Chungong S , Rodier G , Jafari H . Emerg Infect Dis 2017 23 (13) S33-9 The Joint External Evaluation (JEE), a consolidation of the World Health Organization (WHO) International Health Regulations 2005 (IHR 2005) Monitoring and Evaluation Framework and the Global Health Security Agenda country assessment tool, is an objective, voluntary, independent peer-to-peer multisectoral assessment of a country's health security preparedness and response capacity across 19 IHR technical areas. WHO approved the standardized JEE tool in February 2016. The JEE process is wholly transparent; countries request a JEE and are encouraged to make its findings public. Donors (e.g., member states, public and private partners, and other public health institutions) can support countries in addressing identified JEE gaps, and implementing country-led national action plans for health security. Through July 2017, 52 JEEs were completed, and 25 more countries were scheduled across WHO's 6 regions. JEEs facilitate progress toward IHR 2005 implementation, thereby building trust and mutual accountability among countries to detect and respond to public health threats. |
Preventing vaccine-derived poliovirus emergence during the polio endgame
Pons-Salort M , Burns CC , Lyons H , Blake IM , Jafari H , Oberste MS , Kew OM , Grassly NC . PLoS Pathog 2016 12 (7) e1005728 Reversion and spread of vaccine-derived poliovirus (VDPV) to cause outbreaks of poliomyelitis is a rare outcome resulting from immunisation with the live-attenuated oral poliovirus vaccines (OPVs). Global withdrawal of all three OPV serotypes is therefore a key objective of the polio endgame strategic plan, starting with serotype 2 (OPV2) in April 2016. Supplementary immunisation activities (SIAs) with trivalent OPV (tOPV) in advance of this date could mitigate the risks of OPV2 withdrawal by increasing serotype-2 immunity, but may also create new serotype-2 VDPV (VDPV2). Here, we examine the risk factors for VDPV2 emergence and implications for the strategy of tOPV SIAs prior to OPV2 withdrawal. We first developed mathematical models of VDPV2 emergence and spread. We found that in settings with low routine immunisation coverage, the implementation of a single SIA increases the risk of VDPV2 emergence. If routine coverage is 20%, at least 3 SIAs are needed to bring that risk close to zero, and if SIA coverage is low or there are persistently "missed" groups, the risk remains high despite the implementation of multiple SIAs. We then analysed data from Nigeria on the 29 VDPV2 emergences that occurred during 2004-2014. Districts reporting the first case of poliomyelitis associated with a VDPV2 emergence were compared to districts with no VDPV2 emergence in the same 6-month period using conditional logistic regression. In agreement with the model results, the odds of VDPV2 emergence decreased with higher routine immunisation coverage (odds ratio 0.67 for a 10% absolute increase in coverage [95% confidence interval 0.55-0.82]). We also found that the probability of a VDPV2 emergence resulting in poliomyelitis in >1 child was significantly higher in districts with low serotype-2 population immunity. Our results support a strategy of focused tOPV SIAs before OPV2 withdrawal in areas at risk of VDPV2 emergence and in sufficient number to raise population immunity above the threshold permitting VDPV2 circulation. A failure to implement this risk-based approach could mean these SIAs actually increase the risk of VDPV2 emergence and spread. |
The Global Polio Eradication Initiative: progress, lessons learned, and polio legacy transition planning
Cochi SL , Hegg L , Kaur A , Pandak C , Jafari H . Health Aff (Millwood) 2016 35 (2) 277-83 The world is closer than ever to achieving global polio eradication, with record-low polio cases in 2015 and the impending prospect of a polio-free Africa. Tens of millions of volunteers, social mobilizers, and health workers have participated in the Global Polio Eradication Initiative. The program contributes to efforts to deliver other health benefits, including health systems strengthening. As the initiative nears completion after more than twenty-five years, it becomes critical to document and transition the knowledge, lessons learned, assets, and infrastructure accumulated by the initiative to address other health goals and priorities. The primary goals of this process, known as polio legacy transition planning, are both to protect a polio-free world and to ensure that investments in polio eradication will contribute to other health goals after polio is completely eradicated. The initiative is engaged in an extensive transition process of consultations and planning at the global, regional, and country levels. A successful completion of this process will result in a well-planned and -managed conclusion of the initiative that will secure the global public good gained by ending one of the world's most devastating diseases and ensure that these investments provide public health benefits for years to come. |
Possible eradication of wild poliovirus type 3 - worldwide, 2012
Kew OM , Cochi SL , Jafari HS , Wassilak SG , Mast EE , Diop OM , Tangermann RH , Armstrong GL . MMWR Morb Mortal Wkly Rep 2014 63 (45) 1031-1033 In 1988, the World Health Assembly resolved to eradicate polio worldwide. Since then, four of the six World Health Organization (WHO) regions have been certified as polio-free: the Americas in 1994, the Western Pacific Region in 2000, the European Region in 2002, and the South-East Asia Region in 2014. Currently, nearly 80% of the world's population lives in areas certified as polio-free. Certification may be considered when ≥3 years have passed since the last isolation of wild poliovirus (WPV) in the presence of sensitive, certification-standard surveillance. Although regional eradication has been validated in the European Region and the Western Pacific Region, outbreaks resulting from WPV type 1 (WPV1) imported from known endemic areas were detected and controlled in these regions in 2010 and 2011, respectively. The last reported case associated with WPV type 2 (WPV2) was in India in 1999, marking global interruption of WPV2 transmission. The completion of polio eradication was declared a programmatic emergency for public health in 2012, and the international spread of WPV1 was declared a public health emergency of international concern in May 2014. The efforts needed to interrupt all indigenous WPV1 transmission are now being focused on the remaining endemic countries: Nigeria, Afghanistan, and Pakistan. WPV type 3 (WPV3) has not been detected in circulation since November 11, 2012. This report summarizes the evidence of possible global interruption of transmission of WPV3, based on surveillance for acute flaccid paralysis (AFP) and environmental surveillance. |
Polio-free certification and lessons learned - South-East Asia Region, March 2014
Bahl S , Kumar R , Menabde N , Thapa A , McFarland J , Swezy V , Tangermann RH , Jafari HS , Elsner L , Wassilak SG , Kew OM , Cochi SL . MMWR Morb Mortal Wkly Rep 2014 63 (42) 941-6 In 1988, the World Health Assembly resolved to interrupt wild poliovirus (WPV) transmission worldwide. By 2006, the annual number of WPV cases had decreased by more than 99%, and only four remaining countries had never interrupted WPV transmission: Afghanistan, India, Nigeria, and Pakistan. The last confirmed WPV case in India occurred in January 2011, leading the World Health Organization (WHO) South-East Asia Regional Commission for the Certification of Polio Eradication (SEA-RCC) in March 2014 to declare the 11-country South-East Asia Region (SEAR), which includes India, to be free from circulating indigenous WPV. SEAR became the fourth region among WHO's six regions to be certified as having interrupted all indigenous WPV circulation; the Region of the Americas was declared polio-free in 1994, the Western Pacific Region in 2000, and the European Region in 2002. Approximately 80% of the world's population now lives in countries of WHO regions that have been certified polio-free. This report summarizes steps taken to certify polio eradication in SEAR and outlines eradication activities and lessons learned in India, the largest member state in the region and the one for which eradication was the most difficult. |
Global polio eradication initiative: lessons learned and legacy
Cochi SL , Freeman A , Guirguis S , Jafari H , Aylward B . J Infect Dis 2014 210 Suppl 1 S540-6 The world is on the verge of achieving global polio eradication. During >25 years of operations, the Global Polio Eradication Initiative (GPEI) has mobilized and trained millions of volunteers, social mobilizers, and health workers; accessed households untouched by other health initiatives; mapped and brought health interventions to chronically neglected and underserved communities; and established a standardized, real-time global surveillance and response capacity. It is important to document the lessons learned from polio eradication, especially because it is one of the largest ever global health initiatives. The health community has an obligation to ensure that these lessons and the knowledge generated are shared and contribute to real, sustained changes in our approach to global health. We have summarized what we believe are 10 leading lessons learned from the polio eradication initiative. We have the opportunity and obligation to build a better future by applying the lessons learned from GPEI and its infrastructure and unique functions to other global health priorities and initiatives. In so doing, we can extend the global public good gained by ending for all time one of the world's most devastating diseases by also ensuring that these investments provide public health dividends and benefits for years to come. |
An acute flaccid paralysis surveillance-based serosurvey of poliovirus antibodies in Western Uttar Pradesh, India
Bahl S , Gary HE Jr , Jafari H , Sarkar BK , Pathyarch SK , Sethi R , Deshpande J . J Infect Dis 2014 210 Suppl 1 S234-42 BACKGROUND: Despite intensified use of monovalent oral poliovirus type 1 vaccine and improved coverage of immunization campaigns, wild poliovirus type 1 persisted in Indian states of Uttar Pradesh and Bihar during 2006 to 2009. METHODS: A serosurvey was conducted among cases of acute flaccid paralysis in the 25 high-polio-incidence districts of western Uttar Pradesh. Children were recruited by age group (6-11 months, 12-24 months, and 25-69 months) from among cases reported through the acute flaccid paralysis surveillance system between November 2008 and August 2009. RESULTS: Seroprevalence for type 1 wild poliovirus was >96.4% for each age group. The seroprevalence of wild poliovirus types 2 and 3 increased with age, from 36.7% to 73.4% for type 2 and from 39.0% to 74.1% for type 3. In addition to the number of type-specific vaccine doses, father's level of education, being from a Muslim family, height for age, and female sex were the socioeconomic risk factors associated with seronegativity to poliovirus. CONCLUSIONS: The seroprevalence and risk factors identified in this study were consistent with the epidemiology of polio, and the findings were instrumental in optimizing vaccination strategy in western Uttar Pradesh with respect to the choice of OPV types, the frequency of supplementary immunization campaigns, and the urgency to improve routine immunization services. |
Assessing population immunity in a persistently high-risk area for wild poliovirus transmission in India: a serological study in Moradabad, Western Uttar Pradesh
Deshpande JM , Bahl S , Sarkar BK , Estivariz CF , Sharma S , Wolff C , Sethi R , Pathyarch SK , Jain V , Gary HE Jr , Pallansch MA , Jafari H . J Infect Dis 2014 210 Suppl 1 S225-33 BACKGROUND: Moradabad district in Uttar Pradesh reported the highest number of paralytic polio cases in India during 2001-2007. We conducted a study in Moradabad in 2007 to assess seroprevalence against poliovirus types 1, 2, and 3 in children 6-12 and 36-59 months of age to guide future strategies to interrupt wild poliovirus transmission in high-risk areas. METHODS: Children attending 10 health facilities for minor illnesses who met criteria for study inclusion were eligible for enrollment. We recorded vaccination history, weight, and length and tested sera for neutralizing antibodies to poliovirus types 1, 2, and 3. RESULTS: Poliovirus type 1, 2, and 3 seroprevalences were 88% (95% confidence interval [CI], 84%-91%), 70% (95% CI, 66%-75%), and 75% (95% CI, 71%-79%), respectively, among 467 in the younger age group (n = 467), compared with 100% (95% CI, 99%-100%), 97% (95% CI, 95%-98%), and 93% (91%-95%), respectively, among 447 children in the older age group (P < .001 for all serotypes). CONCLUSIONS: This seroprevalence study provided extremely useful information that was used by the program in India to guide immunization policies, such as optimizing the use of different OPV formulations in vaccination campaigns and strengthening routine immunization services. Similar surveys in populations at risk should be performed at regular intervals in countries where the risk of persistence or spread of indigenous or imported wild poliovirus is high. |
Cross-sectional serologic assessment of immunity to poliovirus infection in high-risk areas of northern India
Bahl S , Estivariz CF , Sutter RW , Sarkar BK , Verma H , Jain V , Agrawal A , Rathee M , Shukla H , Pathyarch SK , Sethi R , Wannemuehler KA , Jafari H , Deshpande JM . J Infect Dis 2014 210 Suppl 1 S243-51 INTRODUCTION: The objectives of this survey were to assess the seroprevalence of antibodies to poliovirus types 1 and 3 and the impact of bivalent (types 1 and 3) oral poliovirus vaccine (bOPV) use in immunization campaigns in northern India. METHODS: In August 2010, a 2-stage stratified cluster sampling method identified infants aged 6-7 months in high-risk blocks for wild poliovirus infection. Vaccination history, weight and length, and serum were collected to test for neutralizing antibodies to poliovirus types 1, 2, and 3. RESULTS: Seroprevalences of antibodies to poliovirus types 1, 2, and 3 were 98% (95% confidence interval [CI], 97%-99%), 66% (95% CI, 62%-69%), and 77% (95% CI, 75%-79%), respectively, among 664 infants from Bihar and 616 infants from Uttar Pradesh. Infants had received a median of 3 bOPV doses and 2 monovalent type 1 OPV (mOPV1) doses through campaigns and 3 trivalent OPV (tOPV) doses through routine immunization. Among subjects with 0 tOPV doses, the seroprevalences of antibodies to type 3 were 50%, 77%, and 82% after 2, 3, and 4 bOPV doses, respectively. In multivariable analysis, malnutrition was associated with a lower seroprevalence of type 3 antibodies. CONCLUSIONS: This study confirmed that replacing mOPV1 with bOPV in campaigns was successful in maintaining very high population immunity to type 1 poliovirus and substantially decreasing the immunity gap to type 3 poliovirus. |
Prevalence of asymptomatic poliovirus infection in older children and adults in northern India: analysis of contact and enhanced community surveillance, 2009
Mach O , Verma H , Khandait DW , Sutter RW , O'Connor PM , Pallansch MA , Cochi SL , Linkins RW , Chu SY , Wolff C , Jafari HS . J Infect Dis 2014 210 Suppl 1 S252-8 BACKGROUND: In 2009, enhanced poliovirus surveillance was established in polio-endemic areas of Uttar Pradesh and Bihar, India, to assess poliovirus infection in older individuals. METHODS: In Uttar Pradesh, stool specimens from asymptomatic household and neighborhood contacts of patients with laboratory-confirmed polio were tested for polioviruses. In Bihar, in community-based surveillance, children and adults from 250 randomly selected households in the Kosi River area provided stool and pharyngeal swab samples that were tested for polioviruses. A descriptive analysis of surveillance data was performed. RESULTS: In Uttar Pradesh, 89 of 1842 healthy contacts of case patients with polio (4.8%) were shedding wild poliovirus (WPV); 54 of 85 (63.5%) were ≥5 years of age. Shedding was significantly higher in index households than in neighborhood households (P < .05). In Bihar, 11 of 451 healthy persons (2.4%) were shedding WPV in their stool; 6 of 11 (54.5%) were ≥5 years of age. Mean viral titer was similar in older and younger children. CONCLUSIONS: A high proportion of persons ≥5 years of age were asymptomatically shedding polioviruses. These findings provide indirect evidence that older individuals could have contributed to community transmission of WPV in India. Polio vaccination campaigns generally target children <5 years of age. Expanding this target age group in polio-endemic areas could accelerate polio eradication. |
Progress toward global interruption of wild poliovirus transmission, 2010-2013, and tackling the challenges to complete eradication
Wassilak SG , Oberste MS , Tangermann RH , Diop OM , Jafari HS , Armstrong GL . J Infect Dis 2014 210 Suppl 1 S5-s15 Despite substantial progress, global polio eradication has remained elusive. Indigenous wild poliovirus (WPV) transmission in 4 endemic countries (Afghanistan, India, Nigeria, and Pakistan) persisted into 2010 and outbreaks from imported WPV continued. By 2013, most outbreaks in the interim were promptly controlled. The number of polio-affected districts globally has declined by 74% (from 481 in 2009 to 126 in 2013), including a 79% decrease in the number of affected districts in endemic countries (from 304 to 63). India is now polio-free. The challenges to success in the remaining polio-endemic countries include (1) threats to the security of vaccinators in each country and a ban on polio vaccination in areas of Afghanistan and Pakistan; (2) a risk of decreased government commitment; and (3) remaining surveillance gaps. Coordinated efforts under the International Health Regulations and efforts to mitigate the challenges provide a clear opportunity to soon secure global eradication. |
A world without polio
Cochi SL , Jafari HS , Armstrong GL , Sutter RW , Linkins RW , Pallansch MA , Kew O , Aylward RB . J Infect Dis 2014 210 Suppl 1 S1-4 When this journal last published a special supplement on polio nearly 18 years ago, we lived in a world that was still deeply entangled with this devastating virus [1]. All 3 poliovirus serotypes were still circulating on four continents. Some of the world’s largest countries remained mired in the disease, some with thousands of cases each year. Most tellingly, a number of polio-infected countries, particularly in Africa, had not even introduced core eradication strategies, such as polio national immunization days (NIDs). Both financial and human resources were stretched; worldwide, <250 people were employed full time in a program whose success would eventually require, at its peak, reaching and vaccinating >600 million children multiple times per year. | Despite these realities, optimism and enthusiasm were running high in 1997. Nelson Mandela himself had, just the previous year, launched the continent-wide Polio-Free Africa initiative accompanied by a Kick Polio Out of Africa social mobilization campaign. The massive Operation MECACAR was rapidly clearing virus from the 18 participating countries, spanning 2 continents and coordinating and collaborating through shared poliovirus surveillance, cross-border planning, and synchronized NIDs across the Middle East, Caucasus, Central Asian Republics, and Russian Federation. And in most of the world where the 4 core eradication strategies had been introduced, the number of both cases of polio-paralyzed children and polio-infected countries were falling rapidly (Figure 1). The sense that, with further program expansion, eradication might soon be inevitable was reinforced in 1999 by the eradication of the type 2 wild poliovirus serotype globally; that the last type 2 case was reported from Aligarh, India, suggested that eradication of the other serotypes would follow quickly, both in that country and globally. By 2000, 3 of the 6 regions of the World Health Organization (WHO) had seen their last indigenous poliovirus and were either already certified as polio free or soon would be. Although it was apparent that the original goal of completing wild poliovirus eradication globally by 2000 would be missed, the then Secretary-General of the United Nations, Mr Kofi Annan, convened a special Polio Eradication Summit in September of that year to ensure that the program remained on track for its secondary target of certification of global eradication in 2005. By 2001, polio had been reduced to 475 cases in 10 polio-endemic countries, compared with 350 000 cases in 125 polio-endemic countries in 1988. |
Polio eradication. Efficacy of inactivated poliovirus vaccine in India
Jafari H , Deshpande JM , Sutter RW , Bahl S , Verma H , Ahmad M , Kunwar A , Vishwakarma R , Agarwal A , Jain S , Estivariz C , Sethi R , Molodecky NA , Grassly NC , Pallansch MA , Chatterjee A , Aylward RB . Science 2014 345 (6199) 922-5 Inactivated poliovirus vaccine (IPV) is efficacious against paralytic disease, but its effect on mucosal immunity is debated. We assessed the efficacy of IPV in boosting mucosal immunity. Participants received IPV, bivalent 1 and 3 oral poliovirus vaccine (bOPV), or no vaccine. A bOPV challenge was administered 4 weeks later, and excretion was assessed 3, 7, and 14 days later. Nine hundred and fifty-four participants completed the study. Any fecal shedding of poliovirus type 1 was 8.8, 9.1, and 13.5% in the IPV group and 14.4, 24.1, and 52.4% in the control group by 6- to 11-month, 5-year, and 10-year groups, respectively (IPV versus control: Fisher's exact test P < 0.001). IPV reduced excretion for poliovirus types 1 and 3 between 38.9 and 74.2% and 52.8 and 75.7%, respectively. Thus, IPV in OPV-vaccinated individuals boosts intestinal mucosal immunity. |
Progress toward polio eradication - worldwide, 2013-2014
Moturi EK , Porter KA , Wassilak SG , Tangermann RH , Diop OM , Burns CC , Jafari H . MMWR Morb Mortal Wkly Rep 2014 63 (21) 468-72 In 1988, the World Health Assembly of the World Health Organization (WHO) resolved to interrupt wild poliovirus (WPV) transmission worldwide, and in 2012, the World Health Assembly declared the completion of global polio eradication a programmatic emergency for public health. By 2013, the annual number of WPV cases had decreased by >99% since 1988, and only three countries remained that had never interrupted WPV transmission: Afghanistan, Nigeria, and Pakistan. This report summarizes global progress toward polio eradication during 2013-2014 and updates previous reports. In 2013, a total of 416 WPV cases were reported globally from eight countries, an 86% increase from the 223 WPV cases reported from five countries in 2012. This upsurge in 2013 was caused by a 60% increase in WPV cases detected in Pakistan, and by outbreaks in five previously polio-free countries resulting from international spread of WPV. In 2014, as of May 20, a total of 82 WPV cases had been reported worldwide, compared with 34 cases during the same period in 2013. Polio cases caused by circulating vaccine-derived poliovirus (cVDPV) were detected in eight countries in 2013 and in two countries so far in 2014. To achieve polio eradication in the near future, further efforts are needed to 1) address health worker safety concerns in areas of armed conflict in priority countries, 2) to prevent further spread of WPV and new outbreaks after importation into polio-free countries, and 3) to strengthen surveillance globally. Based on the international spread of WPV to date in 2014, the WHO Director General has issued temporary recommendations to reduce further international exportation of WPV through vaccination of persons traveling from currently polio-affected countries. |
Surveillance during an era of rapidly changing poliovirus epidemiology in India: the role of one vs. two stool specimens in poliovirus detection, 2000-2010
Cardemil CV , Rathee M , Gary H , Wannemuehler K , Anand A , Mach O , Bahl S , Wassilak S , Chu SY , Khera A , Jafari HS , Pallansch MA . Epidemiol Infect 2013 142 (1) 1-9 SUMMARY: Since 2004, efforts to improve poliovirus detection have significantly increased the volume of specimen testing from acute flaccid paralysis (AFP) patients in India. One option to decrease collection and testing burden would be collecting only a single stool specimen instead of two. We investigated stool specimen sensitivity for poliovirus detection in India to estimate the contribution of the second specimen. We reviewed poliovirus isolation data for 303984 children aged <15 years with AFP during 2000-2010. Using maximum-likelihood estimation, we determined specimen sensitivity of each stool specimen, combined sensitivity of both specimens, and sensitivity added by the second specimen. Of 5184 AFP patients with poliovirus isolates, 382 (7.4%) were identified only by the second specimen. Sensitivity was 91.4% for the first specimen and 84.5% for the second specimen; the second specimen added 7.3% sensitivity, giving a combined sensitivity of 98.7%. Combined sensitivity declined, and added sensitivity increased, as the time from paralysis onset to stool collection increased (P = 0.032). The sensitivity added by the second specimen is important to detect the last chains of poliovirus transmission and to achieve certification of polio eradication. For sensitive surveillance, two stool specimens should continue to be collected from each AFP patient in India. |
Comparison of attitudes about polio, polio immunization, and barriers to polio eradication between primary health center physicians and private pediatricians in India
Thacker N , Choudhury P , Gargano LM , Weiss PS , Pazol K , Bahl S , Jafari HS , Arora M , Dubey AP , Vashishtha VM , Agarwal R , Kumar A , Orenstein WA , Omer SB , Hughes JM . Int J Infect Dis 2012 16 (6) e417-23 OBJECTIVES: The objectives of this study were to compare attitudes and perceptions of primary health center (PHC) physicians and pediatricians in Uttar Pradesh and Bihar toward polio disease, immunization, and eradication, and to identify barriers to polio eradication. METHODS: PHC physicians from blocks with at least one confirmed polio case during January 2006 to June 2009 were selected for an in-person survey. Pediatricians were members of the Indian Academy of Pediatrics and were selected from a national directory of members for telephone or mail survey. RESULTS: A higher percentage of PHC physicians than pediatricians reported that an unvaccinated child was susceptible to polio (82.1% vs. 63.0%, p<0.0001) and that polio disease was severe in a child aged 1-5 years (77.7% vs. 62.2%, p<0.0001). PHC physicians and pediatricians expressed confidence in the protectiveness and safety of oral polio vaccine and cited parents' lack of awareness of the importance of polio eradication as an important barrier to eradication. Strengthening routine immunization efforts was reported as the leading intervention required to eradicate polio. CONCLUSIONS: PHC physicians and pediatricians support and have confidence in the success of polio eradication efforts. These findings will be useful for policy-makers involved in the planning of eradication strategies. Providers and parents need to maintain confidence in polio vaccination if polio is to be eradicated. |
Attitudes of pediatricians and primary health center physicians in India concerning routine immunization, barriers to vaccination, and missed opportunities to vaccinate
Gargano LM , Thacker N , Choudhury P , Weiss PS , Pazol K , Bahl S , Jafari HS , Arora M , Orenstein WA , Hughes JM , Omer SB . Pediatr Infect Dis J 2012 31 (2) e37-42 BACKGROUND: India has some of the lowest immunization rates in the world. The objective of this study was to determine the attitudes and practices of pediatricians and physicians working in primary health centers (PHCs) regarding routine immunization and identify correlates of missed opportunities to vaccinate children. We focused on Uttar Pradesh and Bihar, which has faced some of the greatest challenges to achieving high routine immunization coverage. METHODS: A sample of pediatricians from Uttar Pradesh and Bihar was selected from the national membership of the Indian Academy of Pediatrics to participate in either a phone or mail survey. For the sampling frame, the PHCs within selected blocks were enumerated to provide a list from which individuals could be randomly sampled. In all, 614 PHCs in Uttar Pradesh and 159 PHCs were selected for in-person surveys. RESULTS: The response rate for pediatricians was 47% (238/505) and 93% for PHC physicians (719/773). The greatest barrier to vaccinating children with routine immunizations, reported by both pediatricians (95.7%) and PHC physicians (95.1%), was parents' lack of awareness of their importance. Correlates of missing an opportunity to vaccinate for PHC physicians included holding other health care workers responsible for vaccination. PHC physicians were 50% to 70% less likely to vaccinate a child themselves if they thought another type of health care worker was responsible. CONCLUSIONS: Future interventions to increase vaccination coverage should address parental knowledge about the importance of vaccines. Understanding and addressing factors associated with missed opportunities to vaccinate may help improve vaccine coverage in Uttar Pradesh and Bihar. |
Immunogenicity of supplemental doses of poliovirus vaccine for children aged 6-9 months in Moradabad, India: a community-based, randomised controlled trial
Estivariz CF , Jafari H , Sutter RW , John TJ , Jain V , Agarwal A , Verma H , Pallansch MA , Singh AP , Guirguis S , Awale J , Burton A , Bahl S , Chatterjee A , Aylward RB . Lancet Infect Dis 2011 12 (2) 128-35 BACKGROUND: The continued presence of polio in northern India poses challenges to the interruption of wild poliovirus transmission and the management of poliovirus risks in the post-eradication era. We aimed to assess the current immunity profile after routine doses of trivalent oral poliovirus vaccine (OPV) and numerous supplemental doses of type-1 monovalent OPV (mOPV1), and compared the effect of five vaccine formulations and dosages on residual immunity gaps. METHODS: We did a community-based, randomised controlled trial of healthy infants aged 6-9 months at ten sites in Moradabad, India. Serum neutralising antibody was measured before infants were randomly assigned to a study group and given standard-potency or higher-potency mOPV1, intradermal fractional-dose inactivated poliovirus vaccine (IPV, GlaxoSmithKline), or intramuscular full-dose IPV from two different manufacturers (GlaxoSmithKline or Panacea). Follow-up sera were taken at days 7 and 28. Our primary endpoint was an increase of more than four times in antibody titres. We did analyses by per-protocol in children with a blood sample available before, and 28 days after, receiving study vaccine (or who completed study procedures). This trial is registered with Current Controlled Trials, number ISRCTN90744784. FINDINGS: Of 1002 children enrolled, 869 (87%) completed study procedures (ie, blood sample available at day 0 and day 28). At baseline, 862 (99%), 625 (72%), and 418 (48%) had detectable antibodies to poliovirus types 1, 2, and 3, respectively. In children who were type-1 seropositive, an increase of more than four times in antibody titre was detected 28 days after they were given standard-potency mOPV1 (5/13 [38%]), higher-potency mOPV1 (6/21 [29%]), intradermal IPV (9/16 [56%]), GlaxoSmithKline intramuscular IPV (19/22 [86%]), and Panacea intramuscular IPV (11/13 [85%]). In those who were type-2 seronegative, 42 (100%) of 42 seroconverted after GlaxoSmithKline intramuscular IPV, and 24 (59%) of 41 after intradermal IPV (p<0.0001). 87 (90%) of 97 infants who were type-3 seronegative seroconverted after intramuscular IPV, and 21 (36%) of 49 after intradermal IPV (p<0.0001). INTERPRETATION: Supplemental mOPV1 resulted in almost total seroprevalence against poliovirus type 1, which is consistent with recent absence of poliomyelitis cases; whereas seroprevalence against types 2 and 3 was expected for routine vaccination histories. The immunogenicity of IPV produced in India (Panacea) was similar to that of an internationally manufactured IPV (GSK). Intradermal IPV was less immunogenic. FUNDING: Global Alliance for Vaccines and Immunization (GAVI), WHO. |
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