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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 -
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 -
Postgraduate Medical Journal Nov 2022On 22 June 2022, the UK Health Security Agency declared a 'rare national incidence' after finding poliovirus in sewage in London for the first time in nearly 40 years....
On 22 June 2022, the UK Health Security Agency declared a 'rare national incidence' after finding poliovirus in sewage in London for the first time in nearly 40 years. Although no cases of the disease or accompanying paralysis have been documented, the general public's risk is considered minimal. However, public health experts recommend that families are up to date on their polio vaccines to decrease the chance of harm. This article discusses the epidemiology of poliovirus by examining the aetiology of the disease and current mitigation policies implemented to prevent the spread of type 2 vaccine-deceived poliovirus in the UK. Finally, by examining the clinical features of polio, which range from mild gastroenteritis episodes, respiratory sickness, malaise and severe paralysis type, this article offers an advice on particular therapies and tactics to avoid poliovirus outbreaks and other future outbreaks.
Topics: Humans; Poliovirus; Sewage; Poliomyelitis; Paralysis; United Kingdom
PubMed: 36126982
DOI: 10.1136/pmj-2022-142103 -
Risk Analysis : An Official Publication... Feb 2021The polio endgame remains complicated, with many questions about future polio vaccines and national immunization policies. We simulated possible future poliovirus...
The polio endgame remains complicated, with many questions about future polio vaccines and national immunization policies. We simulated possible future poliovirus vaccine routine immunization policies for countries stratified by World Bank Income Levels and estimated the expected costs and cases using an updated integrated dynamic poliovirus transmission, stochastic risk, and economic model. We consider two reference cases scenarios: one that achieves the eradication of all wild polioviruses (WPVs) by 2023 and one in which serotype 1 WPV (WPV1) transmission continues. The results show that the addition of inactivated poliovirus vaccine (IPV) to routine immunization in all countries substantially increased the expected costs of the polio endgame, without substantially increasing its expected health or economic benefits. Adding a second dose of IPV to the routine immunization schedules of countries that currently include a single IPV dose further increases costs and does not appear economically justified in the reference case that does not stop WPV transmission. For the reference case that includes all WPV eradication, adding a second IPV dose at the time of successful oral poliovirus vaccine (OPV) cessation represents a cost-effective option. The risks and costs of needing to restart OPV use change the economics of the polio endgame, although the time horizon used for modeling impacts the overall economic results. National health leaders will want to consider the expected health and economic net benefits of their national polio vaccine strategies recognizing that preferred strategies may differ.
Topics: Cost-Benefit Analysis; Economics, Medical; Global Health; Health Care Costs; Health Policy; Humans; Immunization; Models, Economic; Models, Theoretical; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral; Risk; Stochastic Processes
PubMed: 33590519
DOI: 10.1111/risa.13664 -
PloS One 2024Polio eradication is a current and common strategy throughout the globe. The study of the newly introduced inactivated poliovirus vaccine provides a grasp on the current...
INTRODUCTION
Polio eradication is a current and common strategy throughout the globe. The study of the newly introduced inactivated poliovirus vaccine provides a grasp on the current status of immunization and identifies any disparities in the implementation of the vaccine throughout Ethiopia. Thus, this study aimed to demonstrate the spatial distribution, coverage, and determinants of inactivated poliovirus vaccine immunization in Ethiopia.
METHOD
Spatial distribution and determinants of inactivated poliovirus vaccine immunization in Ethiopia were conducted using Ethiopian mini-demographic and health survey 2019 data. A total of 2,056 weighted children aged 12 to 35 months were included in the analysis. The association between the outcome and explanatory variables was determined by commuting the adjusted odds ratio at a 95% confidence interval. The p-value of less than 0.05 was used to declare factors as significantly associated with the inactivated poliovirus vaccine immunization.
RESULT
The weighted national coverage of inactivated poliovirus vaccine immunization in Ethiopia was 51.58% at a 95% confidence interval (49.42, 53.74). While the rates of inactivated poliovirus vaccine immunization were observed to be greater in Addis Ababa, Tigiray, Amahara, and Benishangul Gumuz provinces and lower in the Somali, Afar, and SNNPR provinces of Ethiopia, Antenatal care follow-up, place of delivery, place of residence, and region were significantly associated with inactivated poliovirus immunization in Ethiopia.
CONCLUSION
The distribution of inactivated poliovirus immunization was spatially variable across Ethiopia. Only about half of the children aged twelve to thirty-five months received the inactivated poliovirus vaccine in the country. The factors, both at the individual and community level, were significantly associated with inactivated poliovirus immunization. Therefore, policies and strategies could benefit from considering antenatal care follow-up, place of delivery, place of residence, and region while implementing inactivated poliovirus vaccine immunization.
Topics: Humans; Ethiopia; Poliovirus Vaccine, Inactivated; Female; Infant; Poliomyelitis; Male; Child, Preschool; Vaccination Coverage; Vaccination; Immunization Programs; Immunization
PubMed: 38820454
DOI: 10.1371/journal.pone.0301933 -
British Journal of Clinical Pharmacology Dec 2021The bivalent oral poliovirus vaccine (bOPV; Sabin types 1 and 3) replaced the trivalent OPV (Sabin types 1, 2 and 3) globally in April 2016. A routine schedule of 1 dose...
AIMS
The bivalent oral poliovirus vaccine (bOPV; Sabin types 1 and 3) replaced the trivalent OPV (Sabin types 1, 2 and 3) globally in April 2016. A routine schedule of 1 dose of inactivated poliovirus vaccine and 3 subsequent doses of bOPV was implemented in Jiangsu simultaneously. The schedule was changed to 2 inactivated poliovirus vaccines + 2 bOPV on 1 September 2019. Although OPV type 2 has been removed, challenges persist because of adverse events following immunization (AEFIs) with bOPV. Therefore, we analysed and evaluated the safety profile of bOPV administered in children based on passive postmarketing AEFI surveillance.
METHODS
We collected all bOPV-related AEFI reports in Jiangsu from the Chinese National AEFI Information System (CNAEFIS) between May 2016 and April 2020. We obtained the administered doses of bOPV from the Jiangsu Provincial Electronic Immunization Registries System. A descriptive analysis was performed.
RESULTS
In total, 2084 bOPV-related AEFIs were retrieved from the CNAEFIS. The overall reporting rate was 24.16 per 100 000 doses. Most AEFIs were nonserious. The most frequently reported symptoms were fever, rash and gastrointestinal disorders. Only 1.34% of AEFIs were serious, which thrombocytopenic purpura accounted for the largest category. Seventeen serious adverse events, including 2 vaccine-associated paralytic poliomyelitis (VAPP) cases, were considered to be related to bOPV vaccination. The rate of VAPP was 0.2 per million doses.
CONCLUSION
AEFI analysis showed that bOPV was well tolerated. The events most frequently reported were nonserious. However, bOPV can still cause VAPP. Attention should be given to risks related to bOPV.
Topics: Child; China; Humans; Immunization Schedule; Infant; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral; Vaccination
PubMed: 34240463
DOI: 10.1111/bcp.14976 -
Frontiers in Immunology 2021We modified a Sabin Oral Poliovirus Vaccine (OPV) vector to permit secretion of the antigens of interest with the goal of improving anti-HIV Env humoral responses in a...
We modified a Sabin Oral Poliovirus Vaccine (OPV) vector to permit secretion of the antigens of interest with the goal of improving anti-HIV Env humoral responses in a SHIV mucosal immunization composed of DNA and recombinant OPVs. We evaluated stimulation of systemic and mucosal cell-mediated and humoral immunity in Rhesus macaques by two regimens, both involving a prime with a SHIVDNA construct producing non-infectious particles formulated in lipid nanoparticles, administered in the oral cavity, and two different viral vector boostings, administered in the oral cavity and intestinally.Group 1 was boosted with rMVA-SHIVBG505, expressing SIV Gag/Pol and HIV Env. Group 2 was boosted with a SHIV-OPV vaccine including a non-secreting SIVCA-p6-OPV, expressing Gag CA, NC and p6 proteins, and a HIVC1-V2-OPV, secreting the C1-V2 fragment of HIV Env, recognized by the broadly neutralizing antibody PG16. A time course analysis of anti-SHIV Gag and Env CD4+ and CD8+ T-cell responses in PBMC and in lymph node, rectal, and vaginal MNC was carried out. Both regimens stimulated significant cell-mediated responses in all compartments, with SHIV-OPV immunization stimulating more significant levels of responses than rMVA- SHIV. Boolean analysis of these responses revealed predominantly monofunctional responses with multifunctional responses also present in all tissues. Stimulation of antibody responses was disappointing in both groups with negative anti-SHIV IgG in plasma, and IgA in salivary, rectal and vaginal secretions being restricted to a few animals. After repeated rectal challenge with SHIV, two Group 1 animals remained uninfected at challenge termination. No significant differences were observed in post-infection viral loads between groups. After the acute phase decline, CD4+ T cell percentages returned to normal levels in vaccinated as well as control animals. However, when compared to controls, vaccinate groups had more significant preservation of PBMC and rectal MNC Th17/Treg ratios, considered the strongest surrogate marker of progression to AIDS. We conclude that the vaccine platforms used in this study are insufficient to stimulate significant humoral immunity at the tested doses and schedule but sufficient to stimulate significant mucosal and systemic cell-mediated immunity, impacting the preservation of key Th17 CD4+ T cells in blood and rectal mucosa.
Topics: Administration, Oral; Animals; Antibody Formation; HIV Antigens; Macaca mulatta; SAIDS Vaccines; Simian Acquired Immunodeficiency Syndrome; Vaccines, DNA; env Gene Products, Human Immunodeficiency Virus
PubMed: 34234789
DOI: 10.3389/fimmu.2021.702705 -
Eastern Mediterranean Health Journal =... Jul 2022The Global Polio Eradication Initiative (GPEI) promised to eradicate polio by 2000, yet the disease remains endemic in 2 countries. The current threat of resurgence in... (Review)
Review
BACKGROUND
The Global Polio Eradication Initiative (GPEI) promised to eradicate polio by 2000, yet the disease remains endemic in 2 countries. The current threat of resurgence in countries with low vaccine coverage and circulating vaccinederived poliovirus (cVDPV) outbreaks due to oral polio vaccine warrants a strategy review.
AIMS
To review the performance of the GPEI from a context based in Pakistan, identifying threats to success and suggesting strategy modifications to help achieve eradication.
METHODS
This was a desk review of the effectiveness of GPEI that was launched in 1988 to eradicate polio by 2000. Subsequent failure to eradicate led to multiple iterations in strategy and planning documents. These documents were reviewed alongside relevant literature to explore the reasons for failure and emergence of cVDPV.
RESULTS
GPEI has been effective in reducing the global polio disease burden by > 99%, but it remains endemic in Pakistan and Afghanistan. cVDPV has caused multiple outbreaks since 2000, and caused 7 times more cases than wild poliovirus (WPV) globally in 2020. The Polio Eradication and Endgame Strategic Plan 2013-2018 aimed to eradicate WPV and cVDPV simultaneously. In 2019, Pakistan saw an upsurge in WPV amid an outbreak of cVDPV infection that continued throughout 2020. Wild polio eradication was not realized and the country was unable to transition to inactivated polio vaccine as predicted in the strategic plan.
CONCLUSION
Over 20 countries now report cVDPV outbreaks and many others are at risk. A country-specific modified strategy is required to eradicate WPV and cVDPV simultaneously, more so in endemic countries.
Topics: Disease Eradication; Disease Outbreaks; Global Health; Humans; Immunization Programs; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral
PubMed: 35959667
DOI: 10.26719/emhj.22.045 -
The Pan African Medical Journal 2021vaccine utilization monitoring provides valuable information for practical forecasting and formulation of strategies to reduce avoidable wastage. This monitoring is weak...
INTRODUCTION
vaccine utilization monitoring provides valuable information for practical forecasting and formulation of strategies to reduce avoidable wastage. This monitoring is weak at county and health facility levels in South Sudan. Lack of national wastage rates could result in inaccurate forecasting, leading to vaccine shortages or overstocking and expiration of vaccines at the subnational and service delivery points. As the country gears to introduce relatively expensive vaccines such as rotavirus and pneumococcal vaccines, a robust vaccine utilization monitoring system must be rolled out. This study provides the best possible estimates of vaccine wastage rates and the possible causes of the wastage.
METHODS
we conducted the study in 45 conveniently sampled health facilities across 9 of the ten states in South Sudan. Vaccine consumption data was prospectively collected to estimate vaccine wastage and the reason for the wastage of each vaccine type.
RESULTS
wastage of lyophilized vaccines, measles, and Bacillus Calmette-Guérin (BCG) ranged between 39.0-66.7% and 52.1-74.3%, respectively, mainly due to doses that were discarded 6 hours after the opening of the vial or at the end of the immunization session. Wastage of liquid vaccines Oral poliovirus vaccines (OPV), Penta, Inactivated polio vaccine (IPV), and Tetanus- diphtheria (Td) ranged between 24.4-49%, 15.5-43.4%, 25.3-57.9%, and 3.8-57.2%, respectively, mainly due to unusable VVM, expiry, unused doses at the end of outreach sessions, and vials without labels.
CONCLUSION
wasted rates for all vaccines were higher than the indicative WHO wastage rates used in South Sudan to forecast national vaccine needs. Unopened vial wastage was high and needs immediate attention.
Topics: Humans; Immunization; Immunization Programs; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral; South Sudan; Vaccination
PubMed: 34887988
DOI: 10.11604/pamj.2021.40.114.28373 -
Vaccine Apr 2023The Global Polio Eradication Initiative (GPEI) faces substantial challenges with managing outbreaks of serotype 2 circulating vaccine-derived polioviruses (cVDPV2s) in...
The Global Polio Eradication Initiative (GPEI) faces substantial challenges with managing outbreaks of serotype 2 circulating vaccine-derived polioviruses (cVDPV2s) in 2021. A full five years after the globally coordinated removal of serotype 2 oral poliovirus vaccine (OPV2) from trivalent oral poliovirus vaccine (tOPV) for use in national immunization programs, cVDPV2s did not die out. Since OPV2 cessation, responses to outbreaks caused by cVDPV2s mainly used serotype 2 monovalent OPV (mOPV2) from a stockpile. A novel vaccine developed from a genetically stabilized OPV2 strain (nOPV2) promises to potentially facilitate outbreak response with lower prospective risks, although its availability and properties in the field remain uncertain. Using an established global poliovirus transmission model and building on a related analysis that characterized the impacts of disruptions in GPEI activities caused by the COVID-19 pandemic, we explore the implications of trade-offs associated with delaying outbreak response to avoid using mOPV2 by waiting for nOPV2 availability (or equivalently, delayed responses waiting for national validation of meeting the criteria for nOPV2 initial use). Consistent with prior modeling, responding as quickly as possible with available mOPV2 promises to reduce the expected burden of disease in the outbreak population and to reduce the chances for the outbreak virus to spread to other areas. Delaying cVDPV2 outbreak response (e.g., modeled as no response January-June 2021) to wait for nOPV2 can considerably increase the total expected cases (e.g., by as many as 1,300 cVDPV2 cases in the African region during 2021-2023) and increases the likelihood of triggering the need to restart widescale preventive use of an OPV2-containing vaccine in national immunization programs that use OPV. Countries should respond to any cVDPV2 outbreaks quickly with rounds that achieve high coverage using any available OPV2, and plan to use nOPV2, if needed, once it becomes widely available based on evidence that it is as effective but safer in populations than mOPV2.
Topics: Humans; Poliovirus Vaccine, Oral; Serogroup; Pandemics; Prospective Studies; COVID-19; Poliovirus; Poliomyelitis; Disease Outbreaks; Global Health
PubMed: 33994237
DOI: 10.1016/j.vaccine.2021.04.061