-
Pathogens (Basel, Switzerland) May 2024Continued investment in the development and application of mathematical models of poliovirus transmission, economics, and risks leads to their use in support of polio... (Review)
Review
Continued investment in the development and application of mathematical models of poliovirus transmission, economics, and risks leads to their use in support of polio endgame strategy development and risk management policies. This study complements an earlier review covering the period 2000-2019 and discusses the evolution of studies published since 2020 by modeling groups supported by the Global Polio Eradication Initiative (GPEI) partners and others. We systematically review modeling papers published in English in peer-reviewed journals from 2020-2024.25 that focus on poliovirus transmission and health economic analyses. In spite of the long-anticipated end of poliovirus transmission and the GPEI sunset, which would lead to the end of its support for modeling, we find that the number of modeling groups supported by GPEI partners doubled and the rate of their publications increased. Modeling continued to play a role in supporting GPEI and national/regional policies, but changes in polio eradication governance, decentralized management and decision-making, and increased heterogeneity in modeling approaches and findings decreased the overall impact of modeling results. Meanwhile, the failure of the 2016 globally coordinated cessation of type 2 oral poliovirus vaccine use for preventive immunization and the introduction of new poliovirus vaccines and formulation, increased the complexity and uncertainty of poliovirus transmission and economic models and policy recommendations during this time.
PubMed: 38921733
DOI: 10.3390/pathogens13060435 -
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 -
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 -
Vaccine Apr 2023Vaccine-derived polioviruses (VDPVs) can emerge from Sabin strain poliovirus serotypes 1, 2, and 3 contained in oral poliovirus vaccine (OPV) after prolonged...
Vaccine-derived polioviruses (VDPVs) can emerge from Sabin strain poliovirus serotypes 1, 2, and 3 contained in oral poliovirus vaccine (OPV) after prolonged person-to-person transmission where population vaccination immunity against polioviruses is suboptimal. VDPVs can cause paralysis indistinguishable from wild polioviruses and outbreaks when community circulation ensues. VDPV serotype 2 outbreaks (cVDPV2) have been documented in The Democratic Republic of the Congo (DRC) since 2005. The nine cVDPV2 outbreaks detected during 2005-2012 were geographically-limited and resulted in 73 paralysis cases. No outbreaks were detected during 2013-2016. During January 1, 2017-December 31, 2021, 19 cVDPV2 outbreaks were detected in DRC. Seventeen of the 19 (including two first detected in Angola) resulted in 235 paralysis cases notified in 84 health zones in 18 of DRC's 26 provinces; no notified paralysis cases were associated with the remaining two outbreaks. The DRC-KAS-3 cVDPV2 outbreak that circulated during 2019-2021, and resulted in 101 paralysis cases in 10 provinces, was the largest recorded in DRC during the reporting period in terms of numbers of paralysis cases and geographic expanse. The 15 outbreaks occurring during 2017-early 2021 were successfully controlled with numerous supplemental immunization activities (SIAs) using monovalent OPV Sabin-strain serotype 2 (mOPV2); however, suboptimal mOPV2 vaccination coverage appears to have seeded the cVDPV2 emergences detected during semester 2, 2018 through 2021. Use of the novel OPV serotype 2 (nOPV2), designed to have greater genetic stability than mOPV2, should help DRC's efforts in controlling the more recent cVDPV2 outbreaks with a much lower risk of further seeding VDPV2 emergence. Improving nOPV2 SIA coverage should decrease the number of SIAs needed to interrupt transmission. DRC needs the support of polio eradication and Essential Immunization (EI) partners to accelerate the country's ongoing initiatives for EI strengthening, introduction of a second dose of inactivated poliovirus vaccine (IPV) to increase protection against paralysis, and improving nOPV2 SIA coverage.
Topics: Humans; Poliovirus; Serogroup; Democratic Republic of the Congo; Poliomyelitis; Poliovirus Vaccine, Oral; Disease Outbreaks
PubMed: 36907733
DOI: 10.1016/j.vaccine.2023.02.042 -
Pathogens (Basel, Switzerland) Mar 2024Inactivated poliovirus vaccine (IPV), available since 1955, became the first vaccine to be used to protect against poliomyelitis. While the immunogenicity of IPV to... (Review)
Review
Inactivated poliovirus vaccine (IPV), available since 1955, became the first vaccine to be used to protect against poliomyelitis. While the immunogenicity of IPV to prevent paralytic poliomyelitis continues to be irrefutable, its requirement for strong containment (due to large quantities of live virus used in the manufacturing process), perceived lack of ability to induce intestinal mucosal immunity, high cost and increased complexity to administer compared to oral polio vaccine (OPV), have limited its use in the global efforts to eradicate poliomyelitis. In order to harvest the full potential of IPV, a program of work has been carried out by the Global Polio Eradication Initiative (GPEI) over the past two decades that has focused on: (1) increasing the scientific knowledge base of IPV; (2) translating new insights and evidence into programmatic action; (3) expanding the IPV manufacturing infrastructure for global demand; and (4) continuing to pursue an ambitious research program to develop more immunogenic and safer-to-produce vaccines. While the knowledge base of IPV continues to expand, further research and product development are necessary to ensure that the program priorities are met (e.g., non-infectious production through virus-like particles, non-transmissible vaccine inducing humoral and intestinal mucosal immunity and new methods for house-to-house administration through micro-needle patches and jet injectors), the discussions have largely moved from whether to how to use this vaccine most effectively. In this review, we summarize recent developments on expanding the science base of IPV and provide insight into policy development and the expansion of IPV manufacturing and production, and finally we provide an update on the current priorities.
PubMed: 38535567
DOI: 10.3390/pathogens13030224 -
The Journal of Infectious Diseases Apr 2021Fractional dose (one-fifth of full intramuscular dose) of inactivated poliovirus vaccine (fIPV) administered intradermally is used as IPV dose-sparing strategy. We... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Fractional dose (one-fifth of full intramuscular dose) of inactivated poliovirus vaccine (fIPV) administered intradermally is used as IPV dose-sparing strategy. We compared the rate of decline of poliovirus antibodies (PVA) in recipients of 2 doses of fIPV or IPV.
METHODS
A community-based randomized controlled trial was conducted in Karachi, Pakistan. Children aged 14 weeks were randomized into fIPV or full IPV (study arms A, B) and received 1 vaccine dose at age 14 weeks and 1 at age 9 months. PVAs were measured at age 14, 18 weeks and 10, 21 months.
RESULTS
Seroprevalence of poliovirus type 2 antibodies in 170/250 (68%) children after 2 IPV or fIPV doses at age 10 months in A and B reached 100% vs 99% (P = .339), and at 21 months, 86% vs 67% (P = .004). Between age 10 and 21 months antibody log2 titers dropped from ≥ 10.5 to 6.8 in A and from 9.2 to 3.7 in B.
CONCLUSIONS
There was a significant decline in antibody titers 12 months following the second IPV dose. The slope of decline was similar for full IPV and fIPV recipients. The results provide further evidence that fIPV is a viable option for IPV dose-sparing.
CLINICAL TRIALS REGISTRATION
NCT03286803.
Topics: Antibodies, Viral; Dose-Response Relationship, Immunologic; Humans; Immunization Schedule; Infant; Injections, Intradermal; Pakistan; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Inactivated; Seroepidemiologic Studies
PubMed: 32798224
DOI: 10.1093/infdis/jiaa504 -
Emerging Infectious Diseases Aug 2023Guatemala implemented wastewater-based poliovirus surveillance in 2018, and three genetically unrelated vaccine-derived polioviruses (VDPVs) were detected in 2019. The... (Review)
Review
Guatemala implemented wastewater-based poliovirus surveillance in 2018, and three genetically unrelated vaccine-derived polioviruses (VDPVs) were detected in 2019. The Ministry of Health (MoH) response included event investigation through institutional and community retrospective case searches for acute flaccid paralysis (AFP) during 2018-2020 and a bivalent oral polio/measles, mumps, and rubella vaccination campaign in September 2019. This response was reviewed by an international expert team in July 2021. During the campaign, 93% of children 6 months <7 years of age received a polio-containing vaccine dose. No AFP cases were detected in the community search; institutional retrospective searches found 37% of unreported AFP cases in 2018‒2020. No additional VDPV was isolated from wastewater. No evidence of circulating VDPV was found; the 3 isolated VDPVs were classified as ambiguous VDPVs by the international team of experts. These detections highlight risk for poliomyelitis reemergence in countries with low polio vaccine coverage.
Topics: Child; Humans; Poliovirus; Poliovirus Vaccine, Oral; Wastewater; Guatemala; Retrospective Studies; Poliomyelitis; Environmental Monitoring
PubMed: 37486156
DOI: 10.3201/eid2908.230236 -
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 -
Vaccine Apr 2023The number and geographic breadth of circulating vaccine-derived poliovirus type 2 (cVDPV2) outbreaks detected after the withdrawal of type 2 containing oral polio...
The number and geographic breadth of circulating vaccine-derived poliovirus type 2 (cVDPV2) outbreaks detected after the withdrawal of type 2 containing oral polio vaccine (April 2016) have exceeded forecasts.Using Acute Flaccid Paralysis (AFP) investigations and environmental surveillance (ES) data from the Global Polio Laboratory Network, we summarize the epidemiology of cVDPV2 outbreaks. Between 01 January 2016 to 31 December 2020, a total of 68 unique cVDPV2 genetic emergences were detected across 34 countries. The cVDPV2 outbreaks have been associated with 1596 acute flaccid paralysis cases across four World Health Organization regions: 962/1596 (60.3%) cases occurred in African Region; 619/1596 (38.8%) in the Eastern Mediterranean Region; 14/1596 (0.9%) in Western-Pacific Region; and 1/1596 (0.1%) in the European Region. As the majority of the cVDPV2 outbreaks have been seeded through monovalent type 2 oral poliovirus vaccine (mOPV2) use in outbreak responses, the introduction of the more stable novel oral poliovirus vaccine will be instrumental in stopping emergence of new cVDPV2 lineages.
Topics: Humans; Poliovirus; Poliovirus Vaccine, Oral; Poliomyelitis; Disease Outbreaks; Global Health
PubMed: 36008232
DOI: 10.1016/j.vaccine.2022.08.008