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1.
Sci Rep ; 14(1): 20425, 2024 09 03.
Artículo en Inglés | MEDLINE | ID: mdl-39227428

RESUMEN

This study focused on the challenges posed by the fluctuating demand for COVID-19 vaccines, considering factors such as side effects, religious objections, and absenteeism, which result in the accumulation of excess vaccines. Recognizing the resulting social, economic, and environmental issues, this study investigated the application of a lateral transshipment policy for the management of the inventory of short-term vaccines, considering related unpredictabilities. A discrete event simulation built on foundational principles derived from a mixed-integer linear programming model was employed to explore the dynamics of mRNA-based vaccine distribution among two hospitals based on lateral transshipment and reordering policies. Through the simulation of various scenarios over periods of 1-30 days, transshipment based on the availability policy is employed to determine the quantity of vaccines to be transshipped, constrained to vial amounts, and the (s, S) inventory system for reordering. The results of this study underscore the efficacy of lateral transshipment, particularly in situations where demand discrepancies exist between hospitals, thereby revealing its superiority over non-transshipment strategies within 7 days.


Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , Vacunas de ARNm , Humanos , Vacunas contra la COVID-19/economía , COVID-19/prevención & control , COVID-19/epidemiología , COVID-19/economía , SARS-CoV-2 , Vacunas Sintéticas/economía
2.
Vaccine ; 42(24): 126107, 2024 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-38971665

RESUMEN

BACKGROUND: The Advisory Committee on Immunization Practices (ACIP) uses the Evidence to Recommendations Framework that includes cost-effectiveness analyses (CEA) for determining vaccine recommendations. ACIP's preference for protecting adults ≥ 65 years is enhanced vaccines, including recombinant influenza vaccine (RIV4), adjuvanted or high dose influenza vaccine. Less is known about the CEA of enhanced vaccines for younger adults. METHODS: We used decision analysis modeling from a societal perspective to determine the cost-effectiveness, measured in quality adjusted life years (QALYs), of RIV4 compared with standard dose quadrivalent influenza vaccine (SD-IIV4) in adults 18-64 years old. Model inputs included 2018-2020 vaccine effectiveness (VE) estimates based on medical record data from a large local health system, 2019-2020 national vaccination and influenza epidemic parameters, with costs and population distributions fitted to the season. RESULTS: Among adults ages 18-64 years, RIV4 cost $94,186/QALY gained, compared to SD-IIV4. Among those 50-64 years old, RIV4 was relatively more cost-effective ($61,329/QALY gained). Cost-effectiveness estimates for 18-64-year-olds were sensitive to the absolute difference in VE between SD-IIV4 and RIV4, among other parameters. Use of RIV4 in 18-64-year-olds would result in fewer cases (669,984), outpatient visits (261,293), hospitalizations (20,046) and deaths (1,018) annually. The majority (59 %; 597 of 1018) of the decreases in deaths occurred in the 50-64-year-olds. CONCLUSIONS: While RIV4 was effective and cost-effective relative to SD-IIV4 for both 50-64-year-old and 18-64-year-old adults, cost-effectiveness was sensitive to small changes in parameters among 18-64-year-olds. Because substantial public health benefits occur with enhanced vaccines, health systems and policy makers may opt for preferential product use in select age/risk groups (e.g., 50-64 year olds) to maximize their cost-benefit ratios.


Asunto(s)
Análisis Costo-Beneficio , Vacunas contra la Influenza , Gripe Humana , Años de Vida Ajustados por Calidad de Vida , Vacunas Sintéticas , Humanos , Adulto , Persona de Mediana Edad , Vacunas contra la Influenza/economía , Vacunas contra la Influenza/administración & dosificación , Vacunas contra la Influenza/inmunología , Adulto Joven , Adolescente , Gripe Humana/prevención & control , Gripe Humana/economía , Masculino , Femenino , Vacunas Sintéticas/economía , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/inmunología , Vacunación/economía , Vacunación/métodos , Eficacia de las Vacunas
6.
Biologicals ; 65: 46-49, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32209300

RESUMEN

On the 17th of October 2019, a workshop was held at Wageningen Bioveterinary Research in Lelystad, the Netherlands, to discuss the obstacles to vaccination in the veterinary field. Participants from academia, OIE, FAO, EC, EMA, USDA, national regulatory and veterinary health authorities, and the animal health industry discussed how availability and access to animal vaccines can be improved not just in the EU and US but also in Low to Middle Income Countries (LMIC) across the world and agreed that this requires innovations in both the scientific and the regulatory field. The workshop called for engaging all stakeholders to improve regulatory acceptance of novel vaccine technologies and encourage their registration. There is a need for better mutual understanding between academia, industry and regulators, and more openness to discuss framework, requirements, and product authorisations, and to converge the regulatory rules between regions. The next leap forward could be a broader application of novel technologies using RNA- or DNA-based vaccine platforms, where the "backbone" is maintained, while the gene of interest coding for an immunogenic protein can be exchanged in a standardised manner. This approach enables rapid response in outbreak situations and should lower the risk and cost of vaccine development.


Asunto(s)
Enfermedades Transmisibles Emergentes/prevención & control , Enfermedades Transmisibles Emergentes/veterinaria , Vacunas de ADN/uso terapéutico , Vacunas Sintéticas/uso terapéutico , Crianza de Animales Domésticos , Animales , Animales Domésticos , Animales Salvajes , Desarrollo de Medicamentos , Participación de los Interesados , Vacunas de ADN/economía , Vacunas Sintéticas/economía , Drogas Veterinarias , Vacunas de ARNm
7.
CMAJ ; 191(34): E932-E939, 2019 08 26.
Artículo en Inglés | MEDLINE | ID: mdl-31451524

RESUMEN

BACKGROUND: Two vaccines against herpes zoster are currently authorized for use in Canada: the recombinant subunit zoster vaccine and live attenuated zoster vaccine. We compared the effectiveness and cost-effectiveness of these 2 vaccines. METHODS: We used a decision analytic static cohort model parametrized with Canadian epidemiologic and economic data. We performed the economic analysis from the health care system perspective, using a lifetime horizon and a 3% discount rate for costs and benefits. The primary outcome was the incremental cost per quality-adjusted life-year (QALY) gained, relative to no vaccination. We ran 30 000 simulations varying all model parameters, including vaccine costs, efficacy and waning. RESULTS: The number needed to vaccinate (NNV) was higher for the live attenuated zoster vaccine than for the recombinant subunit zoster vaccine for all herpes zoster-related events at all ages. For example, in persons exactly 65 years old, for herpes zoster, median NNV was 21 (90% uncertainty interval [UI] 13-31) versus 8 (90% UI 6-18), and for postherpetic neuralgia, NNV was 64 (90% UI 33-93) versus 31 (90% UI 23-73). For the recombinant vaccine, the median cost-effectiveness ratios varied between cost-saving and $25 881 per QALY gained for adults aged 50 years or older. For the live vaccine, the cost-effectiveness ratios varied between cost-saving and $130 587 per QALY gained and were less than $45 000 per QALY gained only for those 65 to 75 years old. Given its higher efficacy, we estimated that the cost for the complete series of the recombinant vaccine could be $150 to $200 more than the cost of the live vaccine and still be considered cost-effective. INTERPRETATION: Our model predicted that the recombinant subunit zoster vaccine is likely cost-effective in Canada for adults 60 years or older, and is likely more cost-effective than live attenuated zoster vaccine. These results have informed updated national and provincial recommendations on herpes zoster vaccination.


Asunto(s)
Análisis Costo-Beneficio , Vacuna contra el Herpes Zóster/economía , Herpes Zóster/prevención & control , Vacunación Masiva/economía , Anciano , Canadá/epidemiología , Técnicas de Apoyo para la Decisión , Herpes Zóster/epidemiología , Vacuna contra el Herpes Zóster/uso terapéutico , Humanos , Persona de Mediana Edad , Neuralgia Posherpética/epidemiología , Neuralgia Posherpética/prevención & control , Años de Vida Ajustados por Calidad de Vida , Vacunas Atenuadas/economía , Vacunas Sintéticas/economía
8.
Vaccine ; 37(27): 3588-3597, 2019 06 12.
Artículo en Inglés | MEDLINE | ID: mdl-31153691

RESUMEN

BACKGROUND: The approval of the extended use of 1-dose varicella vaccine (VVL) in adults aged 50 and older against herpes zoster (HZ) in 2016 and the 2-dose recombinant zoster vaccine (RZV) in 2018 raised the need to evaluate the value for money between these two vaccines. METHODS: We conducted a cost-effectiveness analysis with Markov modelling to evaluate the efficiency of the immunisation programmes from payer's perspective. Eight strategies with different ages to receive VVL or RZV were set, namely: 65-84 year old (y.o.), 70-84 y.o., 75-84 y.o., and 80-84 y.o. VVL- or RZV-strategy. Incremental cost-effectiveness ratios (ICERs) compared with curative care scenario were calculated. The health statuses following the target cohort were as follows: acute HZ followed by recovery, post-herpetic neuralgia followed by recovery, post HZ/PHN, recurrence of HZ, and general death. RESULTS: At the vaccination cost ¥8000 (US$73) for 1-dose ZVL and ¥30,000 (US$273) for 2-dose RZV, ICERs ranged from ¥2,633,587/US$23,942 (age 80-84 y.o.) to ¥3,434,267 or US$31,221 (age 65-84 y.o.)/QALY gained for VVL-strategies; from ¥5,262,227 or US$47,838 (age 80-84 y.o.) to ¥6,278,557 or US$57,078/QALY gained (age 65-84 y.o.) for RZV-strategies. Cost-effectiveness acceptability curves derived from probabilistic sensitivity analyses showed that if the cost-effective threshold was at ¥3,000,000 or US$27,273/QALY, the acceptability was 90.7% and 8.8% for 65-84 VVL-strategy and 65-84 RZV-strategy, respectively; if at ¥5,000,000 or US$45,455/QALY, 56.2% and 43.8%, and if at ¥10,000,000 or US$90,909/QALY 11.9% and 88.1%, respectively. CONCLUSION: Vaccinating individuals aged 65-84 y.o., 70-84 y.o., 75-84 y.o., 80-84 y.o. with VVL or RZV to prevent HZ-associated disease in Japan can be cost-effective from payer's perspective, with vaccination costs at ¥8,000 per shot for VVL, ¥30,000 for 2-dose RZV. While the results suggesting that only 65-84 VVL-strategy and 65-84 RZV strategy should be considered when introducing HZ immunisation programme. The optimal strategy varies depending on the willingness-to-pay threshold.


Asunto(s)
Vacuna contra la Varicela/economía , Vacuna contra la Varicela/inmunología , Análisis Costo-Beneficio , Herpes Zóster/prevención & control , Programas de Inmunización/economía , Neuralgia Posherpética/prevención & control , Anciano , Anciano de 80 o más Años , Vacuna contra la Varicela/administración & dosificación , Femenino , Herpes Zóster/economía , Humanos , Japón , Masculino , Neuralgia Posherpética/economía , Vacunas Atenuadas/economía , Vacunas Atenuadas/inmunología , Vacunas Sintéticas/economía , Vacunas Sintéticas/inmunología
10.
Ann Intern Med ; 170(6): 380-388, 2019 03 19.
Artículo en Inglés | MEDLINE | ID: mdl-30776797

RESUMEN

Background: The U.S. Advisory Committee on Immunization Practices recently developed recommendations for use of a new recombinant zoster vaccine (RZV). Objective: To evaluate the cost-effectiveness of vaccination with RZV compared with zoster vaccine live (ZVL) and no vaccination, the cost-effectiveness of vaccination with RZV for persons who have previously received ZVL, and the cost-effectiveness of preferential vaccination with RZV over ZVL. Design: Simulation (state-transition) model using U.S. epidemiologic, clinical, and cost data. Data Sources: Published data. Target Population: Hypothetical cohort of immunocompetent U.S. adults aged 50 years or older. Time Horizon: Lifetime. Perspective: Societal and health care sector. Intervention: Vaccination with RZV (recommended 2-dose regimen), vaccination with ZVL, and no vaccination. Outcome Measures: The primary outcome measure was the incremental cost-effectiveness ratio (ICER). Results of Base-Case Analysis: For vaccination with RZV compared with no vaccination, ICERs ranged by age from $10 000 to $47 000 per quality-adjusted life-year (QALY), using a societal perspective and assuming 100% completion of the 2-dose RZV regimen. For persons aged 60 years or older, ICERs were less than $60 000 per QALY. Vaccination with ZVL was dominated by vaccination with RZV for all age groups 60 years or older. Results of Sensitivity Analysis: Results were most sensitive to changes in vaccine effectiveness, duration of protection, herpes zoster incidence, and probability of postherpetic neuralgia. Vaccination with RZV after previous administration of ZVL yielded an ICER of less than $60 000 per QALY for persons aged 60 years or older. In probabilistic sensitivity analyses, RZV remained the preferred strategy in at least 95% of simulations, including those with 50% completion of the second dose. Limitation: Few data were available on risk for serious adverse events, adherence to the recommended 2-dose regimen, and probability of recurrent zoster. Conclusion: Vaccination with RZV yields cost-effectiveness ratios lower than those for many recommended adult vaccines, including ZVL. Results are robust over a wide range of plausible values. Primary Funding Source: Centers for Disease Control and Prevention.


Asunto(s)
Vacuna contra el Herpes Zóster/economía , Herpes Zóster/prevención & control , Neuralgia Posherpética/prevención & control , Vacunación/economía , Anciano , Anciano de 80 o más Años , Análisis Costo-Beneficio , Diseño de Investigaciones Epidemiológicas , Política de Salud , Vacuna contra el Herpes Zóster/efectos adversos , Humanos , Cumplimiento de la Medicación , Persona de Mediana Edad , Guías de Práctica Clínica como Asunto , Años de Vida Ajustados por Calidad de Vida , Prevención Secundaria , Sensibilidad y Especificidad , Vacunación/efectos adversos , Vacunas Sintéticas/efectos adversos , Vacunas Sintéticas/economía
11.
Hum Vaccin Immunother ; 15(4): 765-771, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30625011

RESUMEN

Zoster Vaccine Live (ZVL) is marketed in the US since 2008, and a non-live adjuvanted Recombinant Zoster Vaccine (RZV) was approved in 2017. Literature suggests that waning of ZVL efficacy may necessitate additional vaccination. The Advisory Committee on Immunization Practices recommended vaccination with RZV in immunocompetent adults aged 50+ years old, including those previously vaccinated with ZVL. The objective of this study was to determine the cost-effectiveness of vaccinating US adults aged 60+ years old, previously vaccinated with ZVL. The ZOster ecoNomic Analysis (ZONA) model, a deterministic Markov model, was adapted to follow a hypothetical 1 million(M)-person cohort of US adults previously vaccinated with ZVL. Model inputs included demographics, epidemiology, vaccine characteristics, utilities and costs. Costs and quality-adjusted life-years (QALYs) were presented over the lifetimes of the cohort from the year of additional vaccination, discounted 3% annually. The model estimated that, vaccination with RZV 5 years after previous vaccination with ZVL, would reduce disease burden compared with no additional vaccination, resulting in a gain of 1,633 QALYs at a total societal cost of $96M (incremental cost-effectiveness ratio: $58,793/QALY saved). Compared with revaccinating with ZVL, vaccination with RZV would result in a gain of 1,187 QALYs and societal cost savings of almost $84M. Sensitivity, scenario, and threshold analyses demonstrated robustness of these findings. Vaccination with RZV is predicted to be cost-effective relative to no additional vaccination, assuming a threshold of $100,000/QALY, and cost-saving relative to ZVL revaccination of US adults aged 60+ years old who have been previously vaccinated with ZVL.


Asunto(s)
Análisis Costo-Beneficio , Vacuna contra el Herpes Zóster/economía , Herpes Zóster/prevención & control , Vacunación/economía , Adyuvantes Inmunológicos , Factores de Edad , Anciano , Estudios de Cohortes , Femenino , Humanos , Inmunización Secundaria , Masculino , Cadenas de Markov , Persona de Mediana Edad , Años de Vida Ajustados por Calidad de Vida , Estados Unidos , Vacunas Sintéticas/economía
12.
Hum Vaccin Immunother ; 15(1): 34-44, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30130448

RESUMEN

Each year, around 300,000 Herpes Zoster (HZ) cases are observed in the German population, resulting in costs over €182 million to society. The objective of this study was to estimate the potential public health and economic impact of the new Adjuvanted Recombinant Zoster Vaccine (RZV, Shingrix) in the German population ≥ 60 years of age (YOA) and to identify the optimal age of vaccination. We used a static, multi-cohort Markov model that followed a hypothetical cohort of 1 million people ≥ 60 YOA life-long after vaccination using German-specific inputs. Both costs and outcomes were discounted at 3%, the incremental cost-effectiveness ratio (ICER) was calculated based on the societal perspective. The coverage of RZV was set at 40% with a second-dose compliance of 70%. Vaccinating the population aged ≥ 60 YOA would result in 45,000 HZ cases avoided, 1,713 quality-adjusted life years (QALYs) gained at a total cost of approximately €63 million compared to 38,000 cases avoided, 1,545 QALYs gained at a total cost of approximately €68 million in the population ≥ 70 YOA. This would result in an ICER of approximately €37,000 and €44,000/QALY, for the age cohort ≥ 60 and ≥ 70 YOA, respectively. Scenario analyses demonstrated that vaccinating at age 60 or 65 YOA would show greater public health impact and would result in the lowest observed ICER compared to vaccinating at 70 YOA. In conclusion, starting vaccination with RZV in the German population ≥ 60 YOA would demonstrate the best value from a public health and economic standpoint.


Asunto(s)
Análisis Costo-Beneficio , Vacuna contra el Herpes Zóster/economía , Herpes Zóster/prevención & control , Vacunación/economía , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Alemania/epidemiología , Herpes Zóster/epidemiología , Humanos , Cadenas de Markov , Persona de Mediana Edad , Neuralgia Posherpética/epidemiología , Neuralgia Posherpética/prevención & control , Salud Pública , Años de Vida Ajustados por Calidad de Vida , Vacunas Sintéticas/economía
13.
PLoS Negl Trop Dis ; 12(10): e0006870, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30372438

RESUMEN

BACKGROUND: Estimates of current global rabies mortality range from 26,000 to 59,000 deaths per annum. Although pre-exposure prophylaxis using inactivated rabies virus vaccines (IRVs) is effective, it requires two to three doses and is regarded as being too expensive and impractical for inclusion in routine childhood immunization programmes. METHODOLOGY/ PRINCIPAL FINDINGS: Here we report the development of a simian-adenovirus-vectored rabies vaccine intended to enable cost-effective population-wide pre-exposure prophylaxis against rabies. ChAdOx2 RabG uses the chimpanzee adenovirus serotype 68 (AdC68) backbone previously shown to achieve pre-exposure protection against rabies in non-human primates. ChAdOx2 differs from AdC68 in that it contains the human adenovirus serotype 5 (AdHu5) E4 orf6/7 region in place of the AdC68 equivalents, enhancing ease of manufacturing in cell lines which provide AdHu5 E1 proteins in trans. We show that immunogenicity of ChAdOx2 RabG in mice is comparable to that of AdC68 RabG and other adenovirus serotypes expressing rabies virus glycoprotein. High titers of rabies virus neutralizing antibody (VNA) are elicited after a single dose. The relationship between levels of VNA activity and rabies virus glycoprotein monomer-binding antibody differs after immunization with adenovirus-vectored vaccines and IRV vaccines, suggesting routes to further enhancement of the efficacy of the adenovirus-vectored candidates. We also demonstrate that ChAdOx2 RabG can be thermostabilised using a low-cost method suitable for clinical bio-manufacture and ambient-temperature distribution in tropical climates. Finally, we show that a dose-sparing effect can be achieved by formulating ChAdOx2 RabG with a simple chemical adjuvant. This approach could lower the cost of ChAdOx2 RabG and other adenovirus-vectored vaccines. CONCLUSIONS/ SIGNIFICANCE: ChAdOx2 RabG may prove to be a useful tool to reduce the human rabies death toll. We have secured funding for Good Manufacturing Practice- compliant bio-manufacture and Phase I clinical trial of this candidate.


Asunto(s)
Adenovirus de los Simios/genética , Portadores de Fármacos , Profilaxis Pre-Exposición/métodos , Vacunas Antirrábicas/inmunología , Rabia/prevención & control , Adyuvantes Inmunológicos/administración & dosificación , Animales , Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Costos y Análisis de Costo , Estabilidad de Medicamentos , Femenino , Vectores Genéticos , Esquemas de Inmunización , Ratones , Vacunas Antirrábicas/administración & dosificación , Vacunas Antirrábicas/economía , Vacunas Antirrábicas/genética , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/economía , Vacunas Sintéticas/genética , Vacunas Sintéticas/inmunología
14.
Vaccine ; 36(26): 3809-3819, 2018 06 18.
Artículo en Inglés | MEDLINE | ID: mdl-29778517

RESUMEN

Streptococcus pneumoniae is the leading cause of bacterial pneumonia. Although this is a vaccine preventable disease, S. pneumoniae still causes over 1 million deaths per year, mainly in children under the age of five. The biggest disease burden is in the developing world, which is mainly due to unavailability of vaccines due to their high costs. Protein polysaccharide conjugate vaccines are given routinely in the developed world to children to induce a protective antibody response against S. pneumoniae. One of these vaccines is Prevnar13, which targets 13 of the 95 known capsular types. Current vaccine production requires growth of large amounts of the 13 serotypes, and isolation of the capsular polysaccharide that is then chemically coupled to a protein, such as the diphtheria toxoid CRM197, in a multistep expensive procedure. In this study, we design, purify and produce novel recombinant pneumococcal protein polysaccharide conjugate vaccines in Escherichia coli, which act as mini factories for the low-cost production of conjugate vaccines. Recombinant vaccine efficacy was tested in a murine model of pneumococcal pneumonia; ability to protect against invasive disease was compared to that of Prevnar13. This study provides the first proof of principle that protein polysaccharide conjugate vaccines produced in E. coli can be used to prevent pneumococcal infection. Vaccines produced in this manner may provide a low-cost alternative to the current vaccine production methodology.


Asunto(s)
Vacunas Neumococicas/economía , Vacunas Neumococicas/inmunología , Neumonía Neumocócica/prevención & control , Polisacáridos Bacterianos/inmunología , Streptococcus pneumoniae/inmunología , Tecnología Farmacéutica/economía , Tecnología Farmacéutica/métodos , Animales , Modelos Animales de Enfermedad , Escherichia coli/genética , Escherichia coli/metabolismo , Femenino , Ratones , Vacunas Neumococicas/administración & dosificación , Vacunas Neumococicas/aislamiento & purificación , Neumonía Neumocócica/inmunología , Resultado del Tratamiento , Vacunas Conjugadas/administración & dosificación , Vacunas Conjugadas/economía , Vacunas Conjugadas/inmunología , Vacunas Conjugadas/aislamiento & purificación , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/economía , Vacunas Sintéticas/inmunología , Vacunas Sintéticas/aislamiento & purificación
15.
Microb Cell Fact ; 17(1): 17, 2018 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-29402276

RESUMEN

BACKGROUND: Chimeric virus-like particles (VLP) allow the display of foreign antigens on their surface and have proved valuable in the development of safe subunit vaccines or drug delivery. However, finding an inexpensive production system and a VLP scaffold that allows stable incorporation of diverse, large foreign antigens are major challenges in this field. RESULTS: In this study, a versatile and cost-effective platform for chimeric VLP development was established. The membrane integral small surface protein (dS) of the duck hepatitis B virus was chosen as VLP scaffold and the industrially applied and safe yeast Hansenula polymorpha (syn. Pichia angusta, Ogataea polymorpha) as the heterologous expression host. Eight different, large molecular weight antigens of up to 412 amino acids derived from four animal-infecting viruses were genetically fused to the dS and recombinant production strains were isolated. In all cases, the fusion protein was well expressed and upon co-production with dS, chimeric VLP containing both proteins could be generated. Purification was accomplished by a downstream process adapted from the production of a recombinant hepatitis B VLP vaccine. Chimeric VLP were up to 95% pure on protein level and contained up to 33% fusion protein. Immunological data supported surface exposure of the foreign antigens on the native VLP. Approximately 40 mg of chimeric VLP per 100 g dry cell weight could be isolated. This is highly comparable to values reported for the optimized production of human hepatitis B VLP. Purified chimeric VLP were shown to be essentially stable for 6 months at 4 °C. CONCLUSIONS: The dS-based VLP scaffold tolerates the incorporation of a variety of large molecular weight foreign protein sequences. It is applicable for the display of highly immunogenic antigens originating from a variety of pathogens. The yeast-based production system allows cost-effective production that is not limited to small-scale fundamental research. Thus, the dS-based VLP platform is highly efficient for antigen presentation and should be considered in the development of future vaccines.


Asunto(s)
Presentación de Antígeno , Pichia/genética , Vacunas de Partículas Similares a Virus/inmunología , Vacunas de Partículas Similares a Virus/aislamiento & purificación , Animales , Patos , Hepatitis B/inmunología , Antígenos de Superficie de la Hepatitis B/inmunología , Virus de la Hepatitis B del Pato/inmunología , Humanos , Pichia/inmunología , Proteínas Recombinantes de Fusión/inmunología , Proteínas Recombinantes de Fusión/aislamiento & purificación , Vacunas Sintéticas/economía , Vacunas Sintéticas/inmunología , Vacunas de Partículas Similares a Virus/análisis , Vacunas de Partículas Similares a Virus/genética
16.
Hum Vaccin Immunother ; 13(11): 2612-2625, 2017 11 02.
Artículo en Inglés | MEDLINE | ID: mdl-28933657

RESUMEN

Dengue virus (DV) is the etiologic agent of dengue fever, the most significant mosquito-borne viral disease in humans. Most DV vaccine approaches are focused on generating antibody mediated responses; one such DV vaccine is approved for use in humans but its efficacy is limited. While it is clear that T cell responses play important role in DV infection and subsequent disease manifestations, fewer studies are aimed at developing vaccines that induce robust T cells responses. Potent T cell based vaccines require 2 critical components: the identification of specific T cell stimulating MHC associated peptides, and an optimized vaccine delivery vehicle capable of simultaneously delivering the antigens and any required adjuvants. We have previously identified and characterized DV specific HLA-A2 and -A24 binding DV serotypes conserved epitopes, and the feasibility of an epitope based vaccine for DV infection. In this study, we build on those previous studies and describe an investigational DV vaccine using T cell epitopes incorporated into a calcium phosphate nanoparticle (CaPNP) delivery system. This study presents a comprehensive analysis of functional immunogenicity of DV CaPNP/multipeptide formulations in vitro and in vivo and demonstrates the CaPNP/multipeptide vaccine is capable of inducing T cell responses against all 4 serotypes of DV. This synthetic vaccine is also cost effective, straightforward to manufacture, and stable at room temperature in a lyophilized form. This formulation may serve as an effective candidate DV vaccine that protects against all 4 serotypes as either a prophylactic or therapeutic vaccine.


Asunto(s)
Fosfatos de Calcio/química , Vacunas contra el Dengue/inmunología , Epítopos de Linfocito T/química , Inmunización/métodos , Nanopartículas/administración & dosificación , Nanopartículas/química , Animales , Animales Modificados Genéticamente , Antígenos Virales/química , Antígenos Virales/inmunología , Fosfatos de Calcio/administración & dosificación , Dengue/inmunología , Dengue/prevención & control , Dengue/terapia , Vacunas contra el Dengue/administración & dosificación , Vacunas contra el Dengue/efectos adversos , Vacunas contra el Dengue/economía , Virus del Dengue/química , Virus del Dengue/inmunología , Sistemas de Liberación de Medicamentos , Epítopos de Linfocito T/inmunología , Antígeno HLA-A2/inmunología , Humanos , Inmunogenicidad Vacunal , Ratones , Linfocitos T/inmunología , Vacunas de Subunidad/administración & dosificación , Vacunas de Subunidad/efectos adversos , Vacunas de Subunidad/economía , Vacunas de Subunidad/inmunología , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/efectos adversos , Vacunas Sintéticas/economía , Vacunas Sintéticas/inmunología
17.
Vaccine ; 35(1): 53-60, 2017 01 03.
Artículo en Inglés | MEDLINE | ID: mdl-27890400

RESUMEN

BACKGROUND: RTS,S/AS01 is a safe and moderately efficacious vaccine considered for implementation in endemic Africa. Model predictions of impact and cost-effectiveness of this new intervention could aid in country adoption decisions. METHODS: The impact of RTS,S was assessed in 43 countries using an ensemble of models of Plasmodium falciparum epidemiology. Informed by the 32months follow-up data from the phase 3 trial, vaccine effectiveness was evaluated at country levels of malaria parasite prevalence, coverage of control interventions and immunization. Benefits and costs of the program incremental to routine malaria control were evaluated for a four dose schedule: first dose administered at six months, second and third - before 9months, and fourth dose at 27months of age. Sensitivity analyses around vaccine properties, transmission, and economic inputs were conducted. RESULTS: If implemented in all 43 countries the vaccine has the potential to avert 123 (117;129) million malaria episodes over the first 10years. Burden averted averages 18,413 (range of country median estimates 156-40,054) DALYs per 100,000 fully vaccinated children with much variation across settings primarily driven by differences in transmission intensity. At a price of $5 per dose program costs average $39.8 per fully vaccinated child with a median cost-effectiveness ratio of $188 (range $78-$22,448) per DALY averted; the ratio is lower by one third - $136 (range $116-$220) - in settings where parasite prevalence in children aged 2-10years is at or above 10%. CONCLUSION: RTS,S/AS01has the potential to substantially reduce malaria burden in children across Africa. Conditional on assumptions on price, coverage, and vaccine properties, adding RTS,S to routine malaria control interventions would be highly cost-effective. Implementation decisions will need to further consider feasibility of scaling up existing control programs, and operational constraints in reaching children at risk with the schedule.


Asunto(s)
Análisis Costo-Beneficio , Vacunas contra la Malaria/administración & dosificación , Vacunas contra la Malaria/economía , Malaria Falciparum/economía , Malaria Falciparum/prevención & control , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/economía , África/epidemiología , Humanos , Malaria Falciparum/epidemiología
18.
PLoS Med ; 13(11): e1002181, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27898668

RESUMEN

BACKGROUND: Large Phase III trials across Asia and Latin America have recently demonstrated the efficacy of a recombinant, live-attenuated dengue vaccine (Dengvaxia) over the first 25 mo following vaccination. Subsequent data collected in the longer-term follow-up phase, however, have raised concerns about a potential increase in hospitalization risk of subsequent dengue infections, in particular among young, dengue-naïve vaccinees. We here report predictions from eight independent modelling groups on the long-term safety, public health impact, and cost-effectiveness of routine vaccination with Dengvaxia in a range of transmission settings, as characterised by seroprevalence levels among 9-y-olds (SP9). These predictions were conducted for the World Health Organization to inform their recommendations on optimal use of this vaccine. METHODS AND FINDINGS: The models adopted, with small variations, a parsimonious vaccine mode of action that was able to reproduce quantitative features of the observed trial data. The adopted mode of action assumed that vaccination, similarly to natural infection, induces transient, heterologous protection and, further, establishes a long-lasting immunogenic memory, which determines disease severity of subsequent infections. The default vaccination policy considered was routine vaccination of 9-y-old children in a three-dose schedule at 80% coverage. The outcomes examined were the impact of vaccination on infections, symptomatic dengue, hospitalised dengue, deaths, and cost-effectiveness over a 30-y postvaccination period. Case definitions were chosen in accordance with the Phase III trials. All models predicted that in settings with moderate to high dengue endemicity (SP9 ≥ 50%), the default vaccination policy would reduce the burden of dengue disease for the population by 6%-25% (all simulations: -3%-34%) and in high-transmission settings (SP9 ≥ 70%) by 13%-25% (all simulations: 10%- 34%). These endemicity levels are representative of the participating sites in both Phase III trials. In contrast, in settings with low transmission intensity (SP9 ≤ 30%), the models predicted that vaccination could lead to a substantial increase in hospitalisation because of dengue. Modelling reduced vaccine coverage or the addition of catch-up campaigns showed that the impact of vaccination scaled approximately linearly with the number of people vaccinated. In assessing the optimal age of vaccination, we found that targeting older children could increase the net benefit of vaccination in settings with moderate transmission intensity (SP9 = 50%). Overall, vaccination was predicted to be potentially cost-effective in most endemic settings if priced competitively. The results are based on the assumption that the vaccine acts similarly to natural infection. This assumption is consistent with the available trial results but cannot be directly validated in the absence of additional data. Furthermore, uncertainties remain regarding the level of protection provided against disease versus infection and the rate at which vaccine-induced protection declines. CONCLUSIONS: Dengvaxia has the potential to reduce the burden of dengue disease in areas of moderate to high dengue endemicity. However, the potential risks of vaccination in areas with limited exposure to dengue as well as the local costs and benefits of routine vaccination are important considerations for the inclusion of Dengvaxia into existing immunisation programmes. These results were important inputs into WHO global policy for use of this licensed dengue vaccine.


Asunto(s)
Vacunas contra el Dengue/economía , Vacunas contra el Dengue/normas , Modelos Teóricos , Salud Pública , Seguridad , Vacunación/métodos , Niño , Análisis Costo-Beneficio , Vacunas contra el Dengue/efectos adversos , Humanos , Estudios Seroepidemiológicos , Vacunación/efectos adversos , Vacunación/economía , Vacunas Atenuadas/efectos adversos , Vacunas Atenuadas/economía , Vacunas Atenuadas/normas , Vacunas Sintéticas/efectos adversos , Vacunas Sintéticas/economía , Vacunas Sintéticas/normas
20.
Vaccine ; 33(48): 6710-8, 2015 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-26518406

RESUMEN

Recent results from the phase 3 trial of RTS,S/AS01 malaria vaccine show that the vaccine induced partial protection against clinical malaria in infants and children; given the high burden of the disease it is currently considered for use in malaria endemic countries. To inform adoption decisions the paper proposes a generalizable methodology to estimate the cost of vaccine introduction using routinely collected and publicly available data from the cMYP, UNICEF, and WHO-CHOICE. Costing is carried out around a set of generic activities, assumptions, and inputs for delivery of immunization services adapted to a given country and deployment modality to capture among other factors the structure of the EPI program, distribution model, geography, and demographics particular to the setting. The methodology is applied to estimate the cost of RTS,S introduction in Burkina Faso, Ghana, Kenya, Senegal, Tanzania, and Uganda. At an assumed vaccine price of $5 per dose and given our assumptions on coverage and deployment strategy, we estimate total economic program costs for a 6-9 months cohort within $23.11-$28.28 per fully vaccinated child across the 6 countries. Net of procurement, costs at country level are substantial; for instance in Tanzania these could add as much as $4.2 million per year or an additional $2.4 per infant depending on the level of spare capacity in the system. Differences in cost of vaccine introduction across countries are primarily driven by differences in cost of labour. Overall estimates generated with the methodology result in costs within the ranges reported for other new vaccines introduced in SSA and capture multiple sources of heterogeneity in costs across countries. Further validation with data from field trials will support use of the methodology while also serving as a validation for cMYP and WHO-CHOICE as resources for costing health interventions in the region.


Asunto(s)
Costos y Análisis de Costo , Inmunización/economía , Vacunas contra la Malaria/administración & dosificación , Vacunas contra la Malaria/economía , Malaria/prevención & control , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/economía , África/epidemiología , Humanos , Lactante , Malaria/epidemiología
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