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The American Journal of Tropical... Nov 2023Combining oral (OPV) and inactivated (IPV) poliovirus vaccines prevents importation of poliovirus and emergence of circulating vaccine-derived poliovirus. We measured...
Combining oral (OPV) and inactivated (IPV) poliovirus vaccines prevents importation of poliovirus and emergence of circulating vaccine-derived poliovirus. We measured the coverage with IPV and third dose of OPV (OPV-3) and identified determinants of coverage inequality in the most at-risk populations in Ethiopia. A national survey representing 10 partly overlapping underserved populations-pastoralists, conflict-affected areas, urban slums, hard-to-reach settings, developing regions, newly formed regions, internally displaced people (IDPs), refugees, and districts neighboring international and interregional boundaries-was conducted among children 12 to 35 months old (N = 3,646). Socioeconomic inequality was measured using the concentration index (CIX) and decomposed using a regression-based approach. One-third (95% CI: 31.5-34.0%) of the children received OPV-3 and IPV. The dual coverage was below 50% in developing regions (19.2%), pastoralists (22.0%), IDPs (22.3%), districts neighboring international (24.1%) and interregional (33.3%) boundaries, refugees (27.0%), conflict-affected areas (29.3%), newly formed regions (33.5%), and hard-to-reach areas (38.9%). Conversely, coverage was better in urban slums (78%). Children from poorest households, living in villages that do not have health posts, and having limited health facility access had increased odds of not receiving the vaccines. Low paternal education, dissatisfaction with vaccination service, fear of vaccine side effects, living in female-headed households, having employed and less empowered mothers were also risk factors. IPV-OPV3 coverage favored the rich (CIX = -0.161, P < 0.001), and causes of inequality were: inaccessibility of health facilities (13.3%), dissatisfaction with vaccination service (12.8%), and maternal (4.9%) and paternal (4.9%) illiteracy. Polio vaccination coverage in the most at-risk populations in Ethiopia is suboptimal, threatening the polio eradication initiative.
Topics: Child, Preschool; Humans; Infant; Ethiopia; Poliomyelitis; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral; Risk Factors; Vaccination
PubMed: 37748762
DOI: 10.4269/ajtmh.23-0319 -
Expert Review of Vaccines Jul 2019: The inability to successfully stop all use of oral poliovirus vaccine (OPV) as part of the polio endgame and/or the possibilities of reintroduction of live... (Review)
Review
: The inability to successfully stop all use of oral poliovirus vaccine (OPV) as part of the polio endgame and/or the possibilities of reintroduction of live polioviruses after successful OPV cessation may imply the need to restart OPV production and use, either temporarily or permanently. : Complementing prior work that explored the risks of potential OPV restart, we discuss the logistical challenges and implications of restarting OPV in the future, and we develop appropriate assumptions for modeling the possibility of OPV restart. The complexity of phased cessation of the three OPV serotypes implies different potential combinations of OPV use long term. We explore the complexity of polio vaccine choices and key unresolved policy questions that may impact continuing and future use of OPV and/or inactivated poliovirus vaccine (IPV). We then characterize the assumptions required to quantitatively model OPV restart in prospective global-integrated economic policy models for the polio endgame. : Depending on the timing, restarting production of OPV would imply some likely delays associated with ramp-up, re-licensing, and other logistics that would impact the availability and costs of restarting the use of OPV in national immunization programs after globally coordinated cessation of one or more OPV serotypes.
Topics: Disease Eradication; Global Health; Humans; Immunization Programs; Models, Theoretical; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral
PubMed: 31248293
DOI: 10.1080/14760584.2019.1635463 -
Vaccine Feb 2024Delays in achieving polio eradication have led to ongoing risks of poliovirus importations that may cause outbreaks in polio-free countries. Because of the low, but...
Trade-offs of different poliovirus vaccine options for outbreak response in the United States and other countries that only use inactivated poliovirus vaccine (IPV) in routine immunization.
Delays in achieving polio eradication have led to ongoing risks of poliovirus importations that may cause outbreaks in polio-free countries. Because of the low, but non-zero risk of paralysis with oral poliovirus vaccines (OPVs), countries that achieve and maintain high national routine immunization coverage have increasingly shifted to exclusive use of inactivated poliovirus vaccine (IPV) for all preventive immunizations. However, immunization coverage within countries varies, with under-vaccinated subpopulations potentially able to sustain transmission of imported polioviruses and experience local outbreaks. Due to its cost, ease-of-use, and ability to induce mucosal immunity, using OPV as an outbreak control measure offers a more cost-effective option in countries in which OPV remains in use. However, recent polio outbreaks in IPV-only countries raise questions about whether and when IPV use for outbreak response may fail to stop poliovirus transmission and what consequences may follow from using OPV for outbreak response in these countries. We systematically reviewed the literature to identify modeling studies that explored the use of IPV for outbreak response in IPV-only countries. In addition, applying a model of the 2022 type 2 poliovirus outbreak in New York, we characterized the implications of using different OPV formulations for outbreak response instead of IPV. We also explored the hypothetical scenario of the same outbreak except for type 1 poliovirus instead of type 2. We find that using IPV for outbreak response will likely only stop outbreaks for polioviruses of relatively low transmission potential in countries with very high overall immunization coverage, seasonal transmission dynamics, and only if IPV immunization interventions reach some unvaccinated individuals. Using OPV for outbreak response in IPV-only countries poses substantial risks and challenges that require careful consideration, but may represent an option to consider for some outbreaks in some populations depending on the properties of the available vaccines and coverage attainable.
Topics: Humans; United States; Poliovirus Vaccine, Inactivated; Poliovirus; Poliovirus Vaccine, Oral; Poliomyelitis; Disease Outbreaks; Vaccination; New York
PubMed: 38218668
DOI: 10.1016/j.vaccine.2023.12.081 -
Risk Analysis : An Official Publication... Feb 2024Due to the very low, but nonzero, paralysis risks associated with the use of oral poliovirus vaccine (OPV), eradicating poliomyelitis requires ending all OPV use... (Review)
Review
Due to the very low, but nonzero, paralysis risks associated with the use of oral poliovirus vaccine (OPV), eradicating poliomyelitis requires ending all OPV use globally. The Global Polio Eradication Initiative (GPEI) coordinated cessation of Sabin type 2 OPV (OPV2 cessation) in 2016, except for emergency outbreak response. However, as of early 2023, plans for cessation of bivalent OPV (bOPV, containing types 1 and 3 OPV) remain undefined, and OPV2 use for outbreak response continues due to ongoing transmission of type 2 polioviruses and reported type 2 cases. Recent development and use of a genetically stabilized novel type 2 OPV (nOPV2) leads to additional potential vaccine options and increasing complexity in strategies for the polio endgame. Prior applications of integrated global risk, economic, and poliovirus transmission modeling consistent with GPEI strategic plans that preceded OPV2 cessation explored OPV cessation dynamics and the evaluation of options to support globally coordinated risk management efforts. The 2022-2026 GPEI strategic plan highlighted the need for early bOPV cessation planning. We review the published modeling and explore bOPV cessation immunization options as of 2022, assuming that the GPEI partners will not support restart of the use of any OPV type in routine immunization after a globally coordinated cessation of such use. We model the potential consequences of globally coordinating bOPV cessation in 2027, as anticipated in the 2022-2026 GPEI strategic plan. We do not find any options for bOPV cessation likely to succeed without a strategy of bOPV intensification to increase population immunity prior to cessation.
Topics: Humans; Poliovirus Vaccine, Oral; Serogroup; Poliovirus; Poliomyelitis; Poliovirus Vaccine, Inactivated; Global Health; Disease Eradication
PubMed: 37344934
DOI: 10.1111/risa.14158 -
Expert Review of Vaccines 2015The polio eradication endgame aims to bring transmission of all polioviruses to a halt. To achieve this aim, it is essential to block viral replication in individuals... (Review)
Review
The polio eradication endgame aims to bring transmission of all polioviruses to a halt. To achieve this aim, it is essential to block viral replication in individuals via induction of a robust mucosal immune response. Although it has long been recognized that inactivated poliovirus vaccine (IPV) is incapable of inducing a strong mucosal response on its own, it has recently become clear that IPV may boost immunity in the intestinal mucosa among individuals previously immunized with oral poliovirus vaccine. Indeed, mucosal protection appears to be stronger following a booster dose of IPV than oral poliovirus vaccine, especially in older children. Here, we review the available evidence regarding the impact of IPV on mucosal immunity, and consider the implications of this evidence for the polio eradication endgame. We conclude that the implementation of IPV in both routine and supplementary immunization activities has the potential to play a key role in halting poliovirus transmission, and thereby hasten the eradication of polio.
Topics: Disease Eradication; Disease Transmission, Infectious; Humans; Immunity, Mucosal; Poliomyelitis; Poliovirus Vaccine, Inactivated
PubMed: 26159938
DOI: 10.1586/14760584.2015.1052800 -
Vaccine Apr 2023
Topics: Humans; Poliovirus; Poliovirus Vaccine, Oral; Poliomyelitis; Vaccination; Disease Outbreaks; Poliovirus Vaccine, Inactivated; Global Health
PubMed: 36907735
DOI: 10.1016/j.vaccine.2023.02.082 -
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 -
Expert Review of Vaccines 2023Hexaxim is a hexavalent vaccine approved as primary and booster vaccination in infants 6 weeks and older, protecting against diphtheria, tetanus, pertussis,... (Review)
Review
INTRODUCTION
Hexaxim is a hexavalent vaccine approved as primary and booster vaccination in infants 6 weeks and older, protecting against diphtheria, tetanus, pertussis, poliomyelitis, hepatitis B and Haemophilus influenzae type b.
AREAS COVERED
To evaluate the immunogenicity and reactogenicity (safety) of Hexaxim (Hexyon, Hexacima) in primary and booster vaccine schedules; long-term antibody persistence; concomitant use with other childhood vaccines and use in immunocompromised infants. Hexaxim was found to be noninferior to other licensed hexavalent vaccines, being highly immunogenic for all toxoids/antigens and with an acceptable safety profile. It can be administered concomitantly with other childhood vaccines. Hexaxim can be given as a booster for infants primed with Infanrix Hexa and given in a pentavalent-hexavalent-pentavalent series. Hexaxim elicits a similar immune response and safety profile in human immunodeficiency virus (HIV) positive infants. It has the benefit of being a ready-to-use liquid formulation, minimizing dosage errors and preparation time.
EXPERT OPINION
Hexaxim has an acceptable safety profile and provides immunity against all six targeted diseases. It is an acceptable alternative to other hexavalent vaccines on the market. Further studies are required on the use of immunocompromised patients as well as the antibody persistence of each of the vaccine components.
Topics: Infant; Humans; Child; Immunization, Secondary; Immunization Schedule; Diphtheria-Tetanus-Pertussis Vaccine; Haemophilus Vaccines; Poliovirus Vaccine, Inactivated; Hepatitis B Vaccines; Vaccines, Combined; Antibodies, Bacterial
PubMed: 36545777
DOI: 10.1080/14760584.2023.2161519 -
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 -
The Journal of Infectious Diseases Oct 2022The polio eradication endgame called for the removal of trivalent oral poliovirus vaccine (OPV) and introduction of bivalent (types 1 and 3) OPV and inactivated... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
The polio eradication endgame called for the removal of trivalent oral poliovirus vaccine (OPV) and introduction of bivalent (types 1 and 3) OPV and inactivated poliovirus vaccine (IPV). However, supply shortages have delayed IPV administration to tens of millions of infants, and immunogenicity data are currently lacking to guide catch-up vaccination policies.
METHODS
We conducted an open-label randomized clinical trial assessing 2 interventions, full or fractional-dose IPV (fIPV, one-fifth of IPV), administered at age 9-13 months with a second dose given 2 months later. Serum was collected at days 0, 60, 67, and 90 to assess seroconversion, priming, and antibody titer. None received IPV or poliovirus type 2-containing vaccines before enrolment.
RESULTS
A single fIPV dose at age 9-13 months yielded 75% (95% confidence interval [CI], 6%-82%) seroconversion against type 2, whereas 2 fIPV doses resulted in 100% seroconversion compared with 94% (95% CI, 89%-97%) after a single full dose (P < .001). Two doses of IPV resulted in 100% seroconversion.
CONCLUSIONS
Our study confirmed increased IPV immunogenicity when administered at an older age, likely due to reduced interference from maternally derived antibodies. Either 1 full dose of IPV or 2 doses of fIPV could be used to vaccinate missed cohorts, 2 fIPV doses being antigen sparing and more immunogenic.
CLINICAL TRIAL REGISTRATION
NCT03890497.
Topics: Aged; Antibodies, Viral; Bangladesh; Humans; Immunization Schedule; Infant; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral; Vaccination
PubMed: 35575051
DOI: 10.1093/infdis/jiac205