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The Lancet. Global Health Aug 2021The Global Polio Eradication Initiative, launched in 1988 with anticipated completion by 2000, has yet to reach its ultimate goal. The recent surge of polio cases... (Review)
Review
The Global Polio Eradication Initiative, launched in 1988 with anticipated completion by 2000, has yet to reach its ultimate goal. The recent surge of polio cases urgently calls for a reassessment of the programme's current strategy and a new design for the way forward. We propose that the sustainable protection of the world population against paralytic polio cannot be achieved simply by stopping the circulation of poliovirus but must also include maintaining high rates of population immunity indefinitely, which can be created and maintained by implementing global immunisation programmes with improved poliovirus vaccines that create comprehensive immunity without spawning new virulent viruses. The proposed new strategic goal of eradicating the disease rather than the virus would lead to a sustainable eradication of poliomyelitis while simultaneously promoting immunisation against other vaccine-preventable diseases.
Topics: Disease Eradication; Global Health; Humans; Immunization Programs; Poliomyelitis; Poliovirus Vaccines; Program Evaluation
PubMed: 34118192
DOI: 10.1016/S2214-109X(21)00205-9 -
The Journal of Infectious Diseases Sep 2021Both inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV) have contributed to the rapid disappearance of paralytic poliomyelitis from developed...
Both inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV) have contributed to the rapid disappearance of paralytic poliomyelitis from developed countries despite possessing different vaccine properties. Due to cost, ease of use, and other properties, the Expanded Programme on Immunization added OPV to the routine infant immunization schedule for low-income countries in 1974, but variable vaccine uptake and impaired immune responses due to poor sanitation limited the impact. Following launch of the Global Polio Eradication Initiative in 1988, poliomyelitis incidence has been reduced by >99% and types 2 and 3 wild polioviruses are now eradicated, but progress against type 1 polioviruses which are now confined to Afghanistan and Pakistan has slowed due to insecurity, poor access, and other problems. A strategic, globally coordinated replacement of trivalent OPV with bivalent 1, 3 OPV in 2016 reduced the incidence of vaccine-associated paralytic poliomyelitis (VAPP) but allowed the escape of type 2 vaccine-derived polioviruses (VDPV2) in areas with low immunization rates and use of monovalent OPV2 in response seeded new VDPV2 outbreaks and reestablishment of type 2 endemicity. A novel, more genetically stable type 2 OPV vaccine is undergoing clinical evaluation and may soon be deployed prevent or reduce VDPV2 emergences.
Topics: Disease Eradication; Global Health; Humans; Immunization Programs; Immunization Schedule; Infant; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral; Poliovirus Vaccines; Vaccination
PubMed: 34590135
DOI: 10.1093/infdis/jiaa622 -
The Journal of Infectious Diseases Oct 2022Investments in national immunization programs and the Global Polio Eradication Initiative (GPEI) have resulted in substantial reductions in paralytic polio worldwide....
BACKGROUND
Investments in national immunization programs and the Global Polio Eradication Initiative (GPEI) have resulted in substantial reductions in paralytic polio worldwide. However, cases prevented because of investments in immunization programs and GPEI remain incompletely characterized.
METHODS
Using a global model that integrates polio transmission, immunity, and vaccine dynamics, we provide estimates of polio incidence and numbers of paralytic cases prevented. We compare the results with reported cases and estimates historically published by the World Health Organization.
RESULTS
We estimate that the existence and use of polio vaccines prevented 5 million cases of paralytic polio for 1960-1987 and 24 million cases worldwide for 1988-2021 compared to a counterfactual world with no polio vaccines. Since the 1988 resolution to eradicate polio, our estimates suggest GPEI prevented 2.5-6 million cases of paralytic polio compared to counterfactual worlds without GPEI that assume different levels of intensity of polio vaccine use in routine immunization programs.
CONCLUSIONS
Analysis of historical cases provides important context for understanding and communicating the benefits of investments made in polio eradication. Prospective studies will need to explore the expected benefits of future investments, the outcomes of which will depend on whether and when polio is globally eradicated.
Topics: Disease Eradication; Global Health; Humans; Immunization Programs; Poliomyelitis; Poliovirus Vaccines; Prospective Studies
PubMed: 35415741
DOI: 10.1093/infdis/jiac130 -
Revista Chilena de Infectologia :... Dec 2020Oral poliovirus vaccine (OPV) has been instrumental in controlling the polio epidemic, and stands out for its safety, efficacy, ease of oral administration, and low... (Review)
Review
Oral poliovirus vaccine (OPV) has been instrumental in controlling the polio epidemic, and stands out for its safety, efficacy, ease of oral administration, and low cost. However, despite these advantages, as it is a live attenuated virus vaccine, there is the possibility of mutations that confer neurovirulence. Therefore, surveillance for acute flaccid paralysis (AFP) is important, whether associated with live vaccines (VAPP) or vaccine-derived viruses (VDPV). In this review we present important data from Latin America in recent years, where data on VDPV of community transmission, of ambiguous origin and associated with immunodeficiencies are reviewed. Due to the presence of VDPV, it is important to strengthen the epidemiological surveillance system for AFP, with data much lower than those recommended in recent years in the Americas. Additionally, it is essential to improve vaccination coverage to reduce the number of infants at risk of acquiring poliomyelitis. Consequently, we present the vaccination coverage rates with the inactivated vaccine against poliovirus (IPV) in the region and analyze the vaccination programs against poliomyelitis in accordance with the recommendations of the Latin American Society of Pediatric Infectious Diseases (SLIPE; minimum 3 doses of IPV) and the WHO Strategic Advisory Expert Group (SAGE) on Immunization (minimum 2 doses of IPV). The study concludes with recommendations from the authors for the change from OPV to exclusive use of IPV, to increase vaccination coverage and to strengthen surveillance for AFP in the region.
Topics: Child; Humans; Immunization Schedule; Infant; Latin America; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral; Vaccination
PubMed: 33844811
DOI: 10.4067/S0716-10182020000600701 -
Cadernos de Saude Publica 2020This article's objective is to review the "state of the art" in the progress, obstacles, and strategies for achieving global polio eradication. Poliomyelitis control...
This article's objective is to review the "state of the art" in the progress, obstacles, and strategies for achieving global polio eradication. Poliomyelitis control measures began in the 1960s with the advent of two vaccines, the oral polio vaccine (OPV) and the inactivated polio vaccine (IPV). From 1985 to 2020, strategies were implemented to reach the goal of eradication of wild poliovirus (WPV). Following the success with the interruption of indigenous WPV transmission in the Americas, the goal of global eradication was launched. We describe the process of eradication in four historical stages: (1) The advent of the inactivated and oral polio vaccines launched the age of poliomyelitis control; (2) The massive and simultaneous use of OPV had a significant impact on WPV transmission in the late 1970s in Brazil; (3) Domestic and international public policies set the goal of eradication of indigenous WPV transmission in the Americas and defined the epidemiological strategies to interrupt transmission; and (4) The implementation of eradication strategies interrupted indigenous WPV transmission in nearly all regions of the world except Pakistan and Afghanistan, where in 2020 the WPV1 transmission chains have challenged the strategies for containment of the virus. Meanwhile, the persistence and dissemination of circulation of OPV-derived poliovirus in countries with low vaccination coverage, plus the difficulties in replacing OPV with IPV, are currently the obstacles to eradication in the short term. Finally, we discuss the strategies for overcoming the obstacles and challenges in the post-eradication era.
Topics: Afghanistan; Brazil; Disease Eradication; Humans; Immunization Programs; Poliomyelitis; Poliovirus Vaccine, Oral
PubMed: 33146314
DOI: 10.1590/0102-311X00145720 -
Emerging Infectious Diseases Dec 2022Ghana is a yellow fever-endemic country and experienced a vaccine-derived polio outbreak in July 2019. A reactive polio vaccination campaign was conducted in September... (Review)
Review
Ghana is a yellow fever-endemic country and experienced a vaccine-derived polio outbreak in July 2019. A reactive polio vaccination campaign was conducted in September 2019 and preventive yellow fever campaign in November 2020. On March 12, 2020, Ghana confirmed its first COVID-19 cases. During February-August 2021, Ghana received 1,515,450 COVID-19 vaccines through the COVID-19 Vaccines Global Access initiative and other donor agencies. We describe how systems and infrastructure used for polio and yellow fever vaccine deployment and the lessons learned in those campaigns were used to deploy COVID-19 vaccines. During March-August 2021, a total of 1,424,008 vaccine doses were administered in Ghana. By using existing vaccination and health systems, officials in Ghana were able to deploy COVID-19 vaccines within a few months with <5% vaccine wastage and minimal additional resources despite the short shelf-life of vaccines received. These strategies were essential in saving lives in a resource-limited country.
Topics: Humans; Yellow Fever; COVID-19; Pandemics; COVID-19 Vaccines; Vaccination; Immunization Programs; Poliomyelitis; Vaccines; Ghana
PubMed: 36502407
DOI: 10.3201/eid2813.221044 -
The American Journal of Tropical... Dec 2019Poliovirus (PV) environmental surveillance was established in Haiti in three sites each in Port-au-Prince and Gonaïves, where sewage and fecal-influenced environmental... (Comparative Study)
Comparative Study
Poliovirus (PV) environmental surveillance was established in Haiti in three sites each in Port-au-Prince and Gonaïves, where sewage and fecal-influenced environmental open water channel samples were collected monthly from March 2016 to February 2017. The primary objective was to monitor for the emergence of vaccine-derived polioviruses (VDPVs) and the importation and transmission of wild polioviruses (WPVs). A secondary objective was to compare two environmental sample processing methods, the gold standard two-phase separation method and a filter method (bag-mediated filtration system [BMFS]). In addition, non-polio enteroviruses (NPEVs) were characterized by next-generation sequencing using Illumina MiSeq to provide insight on surrogates for PVs. No WPVs or VDPVs were detected at any site with either concentration method. Sabin (vaccine) strain PV type 2 and Sabin strain PV type 1 were found in Port-au-Prince, in March and April samples, respectively. Non-polio enteroviruses were isolated in 75-100% and 0-58% of samples, by either processing method during the reporting period in Port-au-Prince and Gonaïves, respectively. Further analysis of 24 paired Port-au-Prince samples confirmed the detection of a human NPEV and echovirus types E-3, E-6, E-7, E-11, E-19, E-20, and E-29. The comparison of the BMFS filtration method to the two-phase separation method found no significant difference in sensitivity between the two methods (mid--value = 0.55). The experience of one calendar year of sampling has informed the appropriateness of the initially chosen sampling sites, importance of an adequate PV surrogate, and robustness of two processing methods.
Topics: Disease Eradication; Environmental Monitoring; Feces; Filtration; Haiti; High-Throughput Nucleotide Sequencing; Humans; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Oral; Sewage; Water Microbiology
PubMed: 31701857
DOI: 10.4269/ajtmh.19-0469 -
Emerging Infectious Diseases Feb 2021Since May 2019, the Central African Republic has experienced a poliomyelitis outbreak caused by type 2 vaccine-derived polioviruses (VDPV-2s). The outbreak affected...
Since May 2019, the Central African Republic has experienced a poliomyelitis outbreak caused by type 2 vaccine-derived polioviruses (VDPV-2s). The outbreak affected Bangui, the capital city, and 10 districts across the country. The outbreak resulted from several independent emergence events of VDPV-2s featuring recombinant genomes with complex mosaic genomes. The low number of mutations (<20) in the viral capsid protein 1-encoding region compared with the vaccine strain suggests that VDPV-2 had been circulating for a relatively short time (probably <3 years) before being isolated. Environmental surveillance, which relies on a limited number of sampling sites in the Central African Republic and does not cover the whole country, failed to detect the circulation of VDPV-2s before some had induced poliomyelitis in children.
Topics: Central African Republic; Child; Disease Outbreaks; Humans; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Oral
PubMed: 33496226
DOI: 10.3201/eid2702.203173 -
Expert Review of Vaccines 2023Achieving polio eradication requires ensuring the delivery of sufficient supplies of the right vaccines to the right places at the right times. Despite large global... (Review)
Review
BACKGROUND
Achieving polio eradication requires ensuring the delivery of sufficient supplies of the right vaccines to the right places at the right times. Despite large global markets, decades of use, and large quantity purchases of polio vaccines by national immunization programs and the Global Polio Eradication Initiative (GPEI), forecasting demand for the oral poliovirus vaccine (OPV) stockpile remains challenging.
RESEARCH DESIGN AND METHODS
We review OPV stockpile experience compared to pre-2016 expectations, actual demand, and changes in GPEI policies related to the procurement and use of type 2 OPV vaccines. We use available population and immunization schedule data to explore polio vaccine market segmentation, and its role in polio vaccine demand forecasting.
RESULTS
We find that substantial challenges remain in forecasting polio vaccine needs, mainly due to (1) deviations in implementation of plans that formed the basis for earlier forecasts, (2) lack of alignment of tactics/objectives among GPEI partners and other key stakeholders, (3) financing, and (4) uncertainty about development and licensure timelines for new polio vaccines and their field performance characteristics.
CONCLUSIONS
Mismatches between supply and demand over time have led to negative consequences associated with both oversupply and undersupply, as well as excess costs and potentially preventable cases.
Topics: Humans; Poliovirus Vaccine, Oral; Disease Eradication; Poliovirus Vaccines; Poliomyelitis; Vaccination; Immunization Programs; Poliovirus Vaccine, Inactivated; Global Health
PubMed: 37747090
DOI: 10.1080/14760584.2023.2263096 -
Nature Jul 2023Vaccination with Sabin, a live attenuated oral polio vaccine (OPV), results in robust intestinal and humoral immunity and has been key to controlling poliomyelitis. As...
Vaccination with Sabin, a live attenuated oral polio vaccine (OPV), results in robust intestinal and humoral immunity and has been key to controlling poliomyelitis. As with any RNA virus, OPV evolves rapidly to lose attenuating determinants critical to the reacquisition of virulence resulting in vaccine-derived, virulent poliovirus variants. Circulation of these variants within underimmunized populations leads to further evolution of circulating, vaccine-derived poliovirus with higher transmission capacity, representing a significant risk of polio re-emergence. A new type 2 OPV (nOPV2), with promising clinical data on genetic stability and immunogenicity, recently received authorization from the World Health Organization for use in response to circulating, vaccine-derived poliovirus outbreaks. Here we report the development of two additional live attenuated vaccine candidates against type 1 and 3 polioviruses. The candidates were generated by replacing the capsid coding region of nOPV2 with that from Sabin 1 or 3. These chimeric viruses show growth phenotypes similar to nOPV2 and immunogenicity comparable to their parental Sabin strains, but are more attenuated. Our experiments in mice and deep sequencing analysis confirmed that the candidates remain attenuated and preserve all the documented nOPV2 characteristics concerning genetic stability following accelerated virus evolution. Importantly, these vaccine candidates are highly immunogenic in mice as monovalent and multivalent formulations and may contribute to poliovirus eradication.
Topics: Animals; Mice; Disease Models, Animal; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Oral; Vaccines, Attenuated; Disease Eradication
PubMed: 37316671
DOI: 10.1038/s41586-023-06212-3