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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 -
PLoS Pathogens Sep 2021During replication, RNA viruses accumulate genome alterations, such as mutations and deletions. The interactions between individual variants can determine the fitness of...
During replication, RNA viruses accumulate genome alterations, such as mutations and deletions. The interactions between individual variants can determine the fitness of the virus population and, thus, the outcome of infection. To investigate the effects of defective interfering genomes (DI) on wild-type (WT) poliovirus replication, we developed an ordinary differential equation model, which enables exploring the parameter space of the WT and DI competition. We also experimentally examined virus and DI replication kinetics during co-infection, and used these data to infer model parameters. Our model identifies, and our experimental measurements confirm, that the efficiencies of DI genome replication and encapsidation are two most critical parameters determining the outcome of WT replication. However, an equilibrium can be established which enables WT to replicate, albeit to reduced levels.
Topics: Coinfection; Defective Viruses; Humans; Models, Theoretical; Poliovirus; Virus Replication
PubMed: 34570820
DOI: 10.1371/journal.ppat.1009277 -
Journal of Immunological Methods May 2022Next generation poliovirus vaccines are critical to reaching global poliovirus eradication goals. Recent efforts have focused on creating inactivated vaccines using...
Next generation poliovirus vaccines are critical to reaching global poliovirus eradication goals. Recent efforts have focused on creating inactivated vaccines using attenuated Sabin strains that maintain patient safety benefits and immunogenicity of conventional inactivated vaccines while increasing manufacturing safety and lowering production costs, and on developing novel oral vaccines using modified Sabin strains that provide critical mucosal immunity but are further attenuated to minimize risk of reversion to neurovirulence. In addition, there is a push to improve the analytical tools for poliovirus vaccine characterization. Conventional and Sabin inactivated poliovirus vaccines typically rely on standard plate-based ELISA as in vitro D-antigen potency assays in combination with WHO international standards as calibrants. While widely utilized, the current D-antigen ELISA assays have a long time to result (up to 72 h), can suffer from lab-to-lab inconsistency due to non-standardized protocols and reagents, and are inherently singleplex. For D-antigen quantitation, we have developed the VaxArray Polio Assay Kit, a multiplexed, microarray-based immunoassay that uses poliovirus-specific human monoclonal antibodies currently under consideration as standardized reagents for characterizing inactivated Sabin and Salk vaccines. The VaxArray assay can simultaneously quantify all 3 poliovirus serotypes with a time to result of less than 3 h. Here we demonstrate that the assay has limits of quantification suitable for both bioprocess samples and final vaccines, excellent reproducibility and precision, and improved accuracy over an analogous plate-based ELISA. The assay is suitable for adjuvanted combination vaccines, as common vaccine additives and crude matrices do not interfere with quantification, and is intended as a high throughput, standardized quantitation tool to aid inactivated poliovirus vaccine manufacturers in streamlining vaccine development and manufacturing, aiding the global polio eradication effort.
Topics: Antibodies, Viral; Antigens, Viral; Enzyme-Linked Immunosorbent Assay; Humans; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral; Reproducibility of Results; Vaccines, Inactivated
PubMed: 35314144
DOI: 10.1016/j.jim.2022.113259 -
Frontiers in Plant Science 2022Human polioviruses are highly infectious viruses that are spread mainly through the fecal-oral route. Infection of the central nervous system frequently results in... (Review)
Review
Human polioviruses are highly infectious viruses that are spread mainly through the fecal-oral route. Infection of the central nervous system frequently results in irreversible paralysis, a disease called poliomyelitis. Children under five years are mainly affected if they have not acquired immunity through natural infection or vaccination. Current polio vaccines comprise the injectable inactivated polio vaccine (IPV, also called the Salk vaccine) and the live-attenuated oral polio vaccine (OPV, also called the Sabin vaccine). The main limitations of the IPV are the reduced protection at the intestinal mucosa, the site of virus replication, and the high costs for manufacturing due to use of live viruses. While the OPV is more effective and stimulates mucosal immunity, it is manufactured using live-attenuated strains that can revert into pathogenic viruses resulting in major safety concerns and vaccine-derived outbreaks. During the last fifteen years, plant-based poliovirus vaccines have been explored by several groups as a safe and low-cost alternative, and promising results in protection against challenges with viruses and induction of neutralizing antibodies have been obtained. However, low yields and a high frequency in dose administration highlight the need for improvements in polioviral antigen production. In this review, we provide insights into recent efforts to develop plant-made poliovirus candidates, with an emphasis on strategies to optimize the production of viral antigens.
PubMed: 36340406
DOI: 10.3389/fpls.2022.1046346 -
MMWR. Morbidity and Mortality Weekly... Nov 2020Pakistan 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...
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.
Topics: Adolescent; Child; Child, Preschool; Disease Eradication; Humans; Immunization Schedule; Infant; Pakistan; Poliomyelitis; Poliovirus Vaccines; Population Surveillance; Vaccination
PubMed: 33211676
DOI: 10.15585/mmwr.mm6946a5 -
Expert Review of Vaccines Nov 2022Multiple vaccine options are available for polio prevention and risk management. Integrated global risk, economic, and poliovirus transmission modeling provides a tool...
BACKGROUND
Multiple vaccine options are available for polio prevention and risk management. Integrated global risk, economic, and poliovirus transmission modeling provides a tool to explore the dynamics of ending all use of one or more poliovirus vaccines to simplify the polio eradication endgame.
RESEARCH DESIGN AND METHODS
With global reported cases of poliomyelitis trending higher since 2016, we apply an integrated global model to simulate prospective vaccine policies and strategies for OPV-using countries starting with initial conditions that correspond to the epidemiological poliovirus transmission situation at the beginning of 2022.
RESULTS
Abruptly ending all OPV use in 2023 and relying only on IPV to prevent paralysis with current routine immunization coverage would lead to expected reestablished endemic transmission of poliovirus types 1 and 2, and approximately 150,000 expected cases of poliomyelitis per year. Alternatively, if OPV-using countries restart trivalent OPV (tOPV) use for all immunization activities and end IPV use, the model shows the lowest anticipated annual polio cases and lowest costs.
CONCLUSIONS
Poor global risk management and coordination of OPV cessation remain a critical failure mode for the polio endgame, and national and global decision makers face difficult choices due to multiple available polio vaccine options and immunization strategies.
Topics: Humans; Poliovirus Vaccine, Oral; Poliovirus Vaccine, Inactivated; Disease Eradication; Global Health; Poliomyelitis; Poliovirus
PubMed: 36154436
DOI: 10.1080/14760584.2022.2128108 -
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 -
Proceedings of the National Academy of... Jun 2020Regions with insufficient vaccination have hindered worldwide poliomyelitis eradication, as they are vulnerable to sporadic outbreaks through reintroduction of the...
Regions with insufficient vaccination have hindered worldwide poliomyelitis eradication, as they are vulnerable to sporadic outbreaks through reintroduction of the disease. Despite Israel's having been declared polio-free in 1988, a routine sewage surveillance program detected polio in 2013. To curtail transmission, the Israel Ministry of Health launched a vaccine campaign to vaccinate children-who had only received the inactivated polio vaccine-with the oral polio vaccine (OPV). Determining the degree of prosocial motivation in vaccination behavior is challenging because vaccination typically provides direct benefits to the individual as well as indirect benefits to the community by curtailing transmission. However, the Israel OPV campaign provides a unique and excellent opportunity to quantify and model prosocial vaccination as its primary objective was to avert transmission. Using primary survey data and a game-theoretical model, we examine and quantify prosocial behavior during the OPV campaign. We found that the observed vaccination behavior in the Israeli OPV campaign is attributable to prosocial behavior and heterogeneous perceived risk of paralysis based on the individual's comprehension of the prosocial nature of the campaign. We also found that the benefit of increasing comprehension of the prosocial nature of the campaign would be limited if even 24% of the population acts primarily from self-interest, as greater vaccination coverage provides no personal utility to them. Our results suggest that to improve coverage, communication efforts should also focus on alleviating perceived fears surrounding the vaccine.
Topics: Adolescent; Adult; Aged; Altruism; Child; Disease Outbreaks; Game Theory; Humans; Immunization Programs; Israel; Mass Vaccination; Middle Aged; Models, Neurological; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral; Sewage; Surveys and Questionnaires; Vaccination Coverage; Young Adult
PubMed: 32457142
DOI: 10.1073/pnas.1922746117 -
Vaccine Apr 2023Concurrent outbreaks of circulating vaccine-derived poliovirus serotypes 1 and 2 (cVDPV1, cVDPV2) were confirmed in the Republic of the Philippines in September 2019 and...
Concurrent outbreaks of circulating vaccine-derived poliovirus serotypes 1 and 2 (cVDPV1, cVDPV2) were confirmed in the Republic of the Philippines in September 2019 and were subsequently confirmed in Malaysia by early 2020. There is continuous population subgroup movement in specific geographies between the two countries. Outbreak response efforts focused on sequential supplemental immunization activities with monovalent Sabin strain oral poliovirus vaccine type 2 (mOPV2) and bivalent oral poliovirus vaccines (bOPV, containing Sabin strain types 1 and 3) as well as activities to enhance poliovirus surveillance sensitivity to detect virus circulation. A total of six cVDPV1 cases, 13 cVDPV2 cases, and one immunodeficiency-associated vaccine-derived poliovirus type 2 case were detected, and there were 35 cVDPV1 and 31 cVDPV2 isolates from environmental surveillance sewage collection sites. No further cVDPV1 or cVDPV2 have been detected in either country since March 2020. Response efforts in both countries encountered challenges, particularly those caused by the global COVID-19 pandemic. Important lessons were identified and could be useful for other countries that experience outbreaks of concurrent cVDPV serotypes.
Topics: Humans; Poliovirus; Poliomyelitis; Malaysia; Philippines; Pandemics; COVID-19; Poliovirus Vaccine, Oral; Disease Outbreaks
PubMed: 35337673
DOI: 10.1016/j.vaccine.2022.02.022 -
Applied and Environmental Microbiology Apr 2023In the global strategy for polio eradication, environmental surveillance (ES) has been established worldwide to monitor polioviruses. In addition, nonpolio enteroviruses...
In the global strategy for polio eradication, environmental surveillance (ES) has been established worldwide to monitor polioviruses. In addition, nonpolio enteroviruses are simultaneously isolated from wastewater under this ES program. Hence, ES can be used to monitor enteroviruses in sewage to supplement clinical surveillance. In response to the coronavirus disease 2019 (COVID-19) pandemic, we also monitored severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in sewage using the polio ES system in Japan. Enterovirus and SARS-CoV-2 were detected in sewage from January 2019 to December 2021 and from August 2020 to November 2021, respectively. Enterovirus species such as echoviruses and coxsackieviruses were frequently detected by ES in 2019, indicating the circulation of these viruses. After the onset of the COVID-19 pandemic, sewage enterovirus detection and related patient reports were notably reduced in 2020 to 2021, suggesting changes in the hygiene behaviors of the human population in response to the pandemic. Our comparative experiment with a total of 520 reverse transcription-quantitative PCR (RT-qPCR) assays for SARS-CoV-2 detection demonstrated that the solid-based method had a significantly higher detection rate than that of the liquid-based method (24.6% and 15.9%, respectively). Moreover, the resulting RNA concentrations were correlated with the number of new COVID-19 cases (Spearman's = 0.61). These findings indicate that the existing polio ES system can be effectively used for enterovirus and SARS-CoV-2 sewage monitoring using different procedures such as virus isolation and molecular-based detection. Long-term efforts are required to implement surveillance programs for the ongoing COVID-19 pandemic, and they will be required even in the postpandemic era. We adopted the existing polio environmental surveillance (ES) system for SARS-CoV-2 sewage monitoring in Japan as a practical and cost-effective approach. Moreover, the ES system routinely detects enteroviruses from wastewater and, therefore, can be used for enterovirus monitoring. The liquid fraction of the sewage sample is used for poliovirus and enterovirus detection, and the solid fraction can be used for SARS-CoV-2 RNA detection. The present study demonstrates how the existing ES system can be used for monitoring enteroviruses and SARS-CoV-2 in sewage.
Topics: Humans; SARS-CoV-2; Wastewater; Sewage; Japan; Pandemics; RNA, Viral; COVID-19; Enterovirus; Poliomyelitis; Enterovirus Infections; Poliovirus; Environmental Monitoring
PubMed: 36975804
DOI: 10.1128/aem.01853-22