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2.
Vaccimonitor (La Habana, Print) ; 29(1)ene.-abr. 2020. tab, graf
Artículo en Español | LILACS, CUMED | ID: biblio-1094637

RESUMEN

Para el control y prevención del cólera humano se han llevado a cabo diferentes estrategias, entre las cuales, la vacunación es una de las medidas más eficaces. La evaluación preclínica de candidatos vacunales requiere de la demostración de la seguridad de los mismos, para lo cual los estudios toxicológicos son determinantes, al ser obligatorios y altamente regulados. Este estudio tuvo como objetivo demostrar la relevancia de las ratas Sprague Dawley como biomodelo a través de su respuesta inmunológica al candidato vacunal contra el cólera, vax-COLER®, utilizando la técnica de determinación de anticuerpos vibriocidas. Además, evaluar los efectos toxicológicos locales y sistémicos por la administración de una dosis de vax-COLER® a través de la evaluación de síntomas, del consumo de agua y alimentos, el peso corporal y estudios anatomopatológicos. La vacuna vax-COLER® resultó inmunogénica y no evidenció síntomas ni muertes, no hubo cambios en el peso corporal y los consumos de agua y alimentos se comportaron de forma similar entre todos los grupos. Los estudios anatomopatológicos solo mostraron cambios a nivel histológico en los ganglios linfáticos mesentéricos y placas de Peyer de los animales vacunados, con presencia de hiperplasia de los folículos secundarios subcapsulares, hallazgo que difirió significativamente con el resto de los grupos. Se concluye que la vacuna vax-COLER® es inmunogénica en ratas Sprague Dawley, demostrando la relevancia del biomodelo para la evaluación de la seguridad preclínica y que la aplicación de una dosis no produjo efectos tóxicos agudos generales ni locales(AU)


Different strategies have been carried out for the control and prevention of human cholera. Vaccination is one of the most effective strategies. Preclinical evaluation of vaccines needs to prove their safety; whereby toxicological studies are decisive. They are mandatory and highly regulated. This study was aimed to demonstrate the relevance of Sprague Dawley rats as a biomodel, through the immunological response to vax-COLER® cholera vaccine, using the technique of determination of vibriocidal antibodies. In addition, local and systemic toxicological effects were evaluated after administration of a dose of vax-COLER®; through the evaluation of symptoms, water and food consumption, body weight and anatomopathological studies. The vax-COLER® vaccine was immunogenic and showed no symptoms or deaths. No changes in body weight were detected, and food and water consumption were similar among all groups. The anatomopathological studies showed histological changes in the mesenteric lymph nodes and Peyer's patches of the vaccinated animals, with hyperplasia of the subcapsular secondary follicles, finding that differed significantly from the rest of the groups. It is concluded that vax-COLER® vaccine is immunogenic in Sprague-Dawley rats, demonstrating the relevance of the biomodel for the evaluation of preclinical safety, as well as that the application of a single dose did not produce acute general or local toxic effects(AU)


Asunto(s)
Animales , Ratas , Cólera/prevención & control , Medicamentos de Referencia
3.
PLoS Negl Trop Dis ; 14(3): e0007989, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32176695

RESUMEN

After the large influx of Rohingya nationals (termed Forcibly Displaced Myanmar National; FDMN) from Rakhine State of Myanmar to Cox's Bazar in Bangladesh, it was apparent that outbreaks of cholera was very likely in this setting where people were living under adverse water and sanitation conditions. Large campaigns of oral cholera vaccine (OCV) were carried out as a preemptive measure to control cholera epidemics. The aim of the study was to evaluate the immune responses of healthy adults and children after administration of two doses of OCV at 14 days interval in FDMN population and compare with the response observed in Bangladeshi's vaccinated earlier. A cross-sectional immunogenicity study was conducted among FDMNs of three age cohort; in adults (18+years; n = 83), in older children (6-17 years; n = 63) and in younger children (1-5 years; n = 80). Capillary blood was collected at three time points to measure vibriocidal antibodies using either plasma or dried blood spot (DBS) specimens. There was a significant increase of responder frequency of vibriocidal antibody titer at day 14 in all groups for Vibrio cholerae O1 (Ogawa/Inaba: adults-64%/64%, older children-70%/89% and younger children-51%/75%). There was no overall difference of vibriocidal antibody titer between FDMN and Bangladeshi population at baseline (p = 0.07-0.08) and at day 14, day 28 in all age groups for both serotypes. The seroconversion rate and geometric mean titer (GMT) of either serotype were comparable using both plasma and DBS specimens. These results showed that OCV is capable of inducing robust immune responses in adults and children among the FDMN population which is comparable to that seen in Bangladeshi participants in different age groups or that reported from other cholera endemic countries. Our results also suggest that the displaced population were exposed to V. cholerae prior to seeking shelter in Bangladesh.


Asunto(s)
Vacunas contra el Cólera/administración & dosificación , Vacunas contra el Cólera/inmunología , Cólera/prevención & control , Refugiados , Administración Oral , Adolescente , Adulto , Anticuerpos Antibacterianos/sangre , Bangladesh , Actividad Bactericida de la Sangre , Niño , Preescolar , Estudios Transversales , Femenino , Voluntarios Sanos , Humanos , Esquemas de Inmunización , Lactante , Masculino , Persona de Mediana Edad , Mianmar , Serogrupo , Vacunas de Productos Inactivados/administración & dosificación , Vacunas de Productos Inactivados/inmunología , Vibrio cholerae O1/clasificación , Vibrio cholerae O1/inmunología , Adulto Joven
4.
BMC Infect Dis ; 20(1): 226, 2020 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-32183745

RESUMEN

BACKGROUND: Rapid control of cholera outbreaks is a significant challenge in overpopulated urban areas. During late-2017, Kinshasa, the capital of the Democratic Republic of the Congo, experienced a cholera outbreak that showed potential to spread throughout the city. A novel targeted water and hygiene response strategy was implemented to quickly stem the outbreak. METHODS: We describe the first implementation of the cluster grid response strategy carried out in the community during the cholera outbreak in Kinshasa, in which response activities targeted cholera case clusters using a grid approach. Interventions focused on emergency water supply, household water treatment and safe storage, home disinfection and hygiene promotion. We also performed a preliminary community trial study to assess the temporal pattern of the outbreak before and after response interventions were implemented. Cholera surveillance databases from the Ministry of Health were analyzed to assess the spatiotemporal dynamics of the outbreak using epidemic curves and maps. RESULTS: From January 2017 to November 2018, a total of 1712 suspected cholera cases were reported in Kinshasa. During this period, the most affected health zones included Binza Météo, Limeté, Kokolo, Kintambo and Kingabwa. Following implementation of the response strategy, the weekly cholera case numbers in Binza Météo, Kintambo and Limeté decreased by an average of 57% after 2 weeks and 86% after 4 weeks. The total weekly case numbers throughout Kinshasa Province dropped by 71% 4 weeks after the peak of the outbreak. CONCLUSION: During the 2017-2018 period, Kinshasa experienced a sharp increase in cholera case numbers. To contain the outbreak, water supply and hygiene response interventions targeted case households, nearby neighbors and public areas in case clusters using a grid approach. Following implementation of the response, the outbreak in Kinshasa was quickly brought under control. A similar approach may be adapted to quickly interrupt cholera transmission in other urban settings.


Asunto(s)
Cólera/epidemiología , Abastecimiento de Agua/métodos , Cólera/prevención & control , Ciudades , República Democrática del Congo/epidemiología , Brotes de Enfermedades/prevención & control , Agua Potable/química , Agua Potable/microbiología , Composición Familiar , Femenino , Humanos , Higiene , Control de Infecciones/métodos , Masculino , Purificación del Agua
6.
PLoS Negl Trop Dis ; 14(1): e0007967, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-32004316

RESUMEN

Oral cholera vaccine (OCV) has increasingly been used as an outbreak control measure, but vaccine shortages limit its application. A two-dose OCV campaign targeting residents aged over 1 year was launched in three rural Communes of Southern Haiti during an outbreak following Hurricane Matthew in October 2016. Door-to-door and fixed-site strategies were employed and mobile teams delivered vaccines to hard-to-reach communities. This was the first campaign to use the recently pre-qualified OCV, Euvichol. The study objective was to estimate post-campaign vaccination coverage in order to evaluate the campaign and guide future outbreak control strategies. We conducted a cluster survey with sampling based on random GPS points. We identified clusters of five households and included all members eligible for vaccination. Local residents collected data through face-to-face interviews. Coverage was estimated, accounting for the clustered sampling, and 95% confidence intervals calculated. 435 clusters, 2,100 households and 9,086 people were included (99% response rate). Across the three communes respectively, coverage by recall was: 80.7% (95% CI:76.8-84.1), 82.6% (78.1-86.4), and 82.3% (79.0-85.2) for two doses and 94.2% (90.8-96.4), 91.8% (87-94.9), and 93.8% (90.8-95.9) for at least one dose. Coverage varied by less than 9% across age groups and was similar among males and females. Participants obtained vaccines from door-to-door vaccinators (53%) and fixed sites (47%). Most participants heard about the campaign through community 'criers' (58%). Despite hard-to-reach communities, high coverage was achieved in all areas through combining different vaccine delivery strategies and extensive community mobilisation. Emergency OCV campaigns are a viable option for outbreak control and where possible multiple strategies should be used in combination. Euvichol will help alleviate the OCV shortage but effectiveness studies in outbreaks should be done.


Asunto(s)
Vacunas contra el Cólera/administración & dosificación , Cólera/prevención & control , Vacunación Masiva/métodos , Cobertura de Vacunación , Adolescente , Adulto , Niño , Preescolar , Cólera/epidemiología , Vacunas contra el Cólera/provisión & distribución , Análisis por Conglomerados , Recolección de Datos , Brotes de Enfermedades , Composición Familiar , Femenino , Haití/epidemiología , Humanos , Lactante , Masculino , Población Rural
7.
PLoS One ; 15(1): e0226483, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31905206

RESUMEN

Modern societies are exposed to a myriad of risks ranging from disease to natural hazards and technological disruptions. Exploring how the awareness of risk spreads and how it triggers a diffusion of coping strategies is prominent in the research agenda of various domains. It requires a deep understanding of how individuals perceive risks and communicate about the effectiveness of protective measures, highlighting learning and social interaction as the core mechanisms driving such processes. Methodological approaches that range from purely physics-based diffusion models to data-driven environmental methods rely on agent-based modeling to accommodate context-dependent learning and social interactions in a diffusion process. Mixing agent-based modeling with data-driven machine learning has become popularity. However, little attention has been paid to the role of intelligent learning in risk appraisal and protective decisions, whether used in an individual or a collective process. The differences between collective learning and individual learning have not been sufficiently explored in diffusion modeling in general and in agent-based models of socio-environmental systems in particular. To address this research gap, we explored the implications of intelligent learning on the gradient from individual to collective learning, using an agent-based model enhanced by machine learning. Our simulation experiments showed that individual intelligent judgement about risks and the selection of coping strategies by groups with majority votes were outperformed by leader-based groups and even individuals deciding alone. Social interactions appeared essential for both individual learning and group learning. The choice of how to represent social learning in an agent-based model could be driven by existing cultural and social norms prevalent in a modeled society.


Asunto(s)
Adaptación Psicológica , Cólera/psicología , Epidemias/prevención & control , Relaciones Interpersonales , Aprendizaje Automático , Modelos Teóricos , Conducta Social , Cólera/epidemiología , Cólera/etiología , Cólera/prevención & control , Simulación por Computador , Toma de Decisiones , Humanos , Factores de Riesgo , Aprendizaje Social
8.
PLoS One ; 15(1): e0226549, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31914164

RESUMEN

INTRODUCTION: Cholera remains a frequent cause of outbreaks globally, particularly in areas with inadequate water, sanitation and hygiene (WASH) services. Cholera is spread through faecal-oral routes, and studies demonstrate that ingestion of Vibrio cholerae occurs from consuming contaminated food and water, contact with cholera cases and transmission from contaminated environmental point sources. WASH guidelines recommending interventions for the prevention and control of cholera are numerous and vary considerably in their recommendations. To date, there has been no review of practice guidelines used in cholera prevention and control programmes. METHODS: We systematically searched international agency websites to identify WASH intervention guidelines used in cholera programmes in endemic and epidemic settings. Recommendations listed in the guidelines were extracted, categorised and analysed. Analysis was based on consistency, concordance and recommendations were classified on the basis of whether the interventions targeted within-household or community-level transmission. RESULTS: Eight international guidelines were included in this review: three by non-governmental organisations (NGOs), one from a non-profit organisation (NPO), three from multilateral organisations and one from a research institution. There were 95 distinct recommendations identified, and concordance among guidelines was poor to fair. All categories of WASH interventions were featured in the guidelines. The majority of recommendations targeted community-level transmission (45%), 35% targeted within-household transmission and 20% both. CONCLUSIONS: Recent evidence suggests that interventions for effective cholera control and response to epidemics should focus on case-centred approaches and within-household transmission. Guidelines did consistently propose interventions targeting transmission within households. However, the majority of recommendations listed in guidelines targeted community-level transmission and tended to be more focused on preventing contamination of the environment by cases or recurrent outbreaks, and the level of service required to interrupt community-level transmission was often not specified. The guidelines in current use were varied and interpretation may be difficult when conflicting recommendations are provided. Future editions of guidelines should reflect on the inclusion of evidence-based approaches, cholera transmission models and resource-efficient strategies.


Asunto(s)
Cólera/prevención & control , Brotes de Enfermedades/prevención & control , Epidemias/prevención & control , Composición Familiar , Guías como Asunto/normas , Saneamiento/métodos , Purificación del Agua/métodos , Cólera/microbiología , Cólera/transmisión , Humanos , Agencias Internacionales , Microbiología del Agua
9.
Am J Trop Med Hyg ; 102(3): 491-493, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31971151

RESUMEN

The American Committee on Immunization Practices recommends the use of the oral cholera vaccine (OCV) in international travelers aged 18-64 years who visit areas of active cholera transmission. CDC Travelers' Health Branch currently tracks areas of active cholera transmission and posts this information on their country-specific destination web pages at https://wwwnc.cdc.gov/travel/destinations/list. Lessons learned from a webinar conducted among health care providers have led to improvements in how CDC shares information on the OCV. Here, we summarize the major considerations for providers offering the OCV to U.S. travelers and indicate where they can find more information.


Asunto(s)
Vacunas contra el Cólera/administración & dosificación , Vacunas contra el Cólera/inmunología , Cólera/prevención & control , Viaje , Administración Oral , Adolescente , Adulto , Centers for Disease Control and Prevention, U.S. , Humanos , Persona de Mediana Edad , Personal Militar , Guías de Práctica Clínica como Asunto , Estados Unidos , Vacunación , Adulto Joven
10.
Am J Trop Med Hyg ; 102(1): 48-57, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31769402

RESUMEN

The attenuated recombinant Vibrio cholerae O1 vaccine strain CVD 103-HgR, redeveloped as PXVX0200, elicits a rapid serum vibriocidal antibody (SVA) response and protects against cholera-induced diarrhea in adult volunteer challenge trials but has not been studied in children in developed countries. We performed a phase 4, placebo-controlled, double-blind, multicenter study to assess the safety, immunogenicity, and tolerability of a single, oral dose of PXVX0200 in children and adolescents aged 6-17 years in the United States and bridged immunogenicity to adults aged 18-45 years from a separate lot consistency study. Volunteers were randomized to receive a single dose of 1 × 109 colony forming units (CFU) of PXVX0200 or placebo. Immunogenicity endpoints included SVA levels on days 1, 11, and 29 in volunteers aged 6-17 years and also on days 91 and 181 in volunteers aged 12-17 years. Safety was assessed by comparing solicited signs and symptoms on days 1-8, unsolicited adverse events (AEs) through day 29, and serious AEs through day 181. A total of 374 participants were enrolled, comprising 321 vaccine and 53 placebo recipients. The SVA seroconversion rates 10 days after immunization were 98.6% and 2.1% in vaccine and placebo recipients, respectively, and the vaccine seroconversion rate was non-inferior to the 93.5% rate seen in adults aged 18-45 years. Most reactogenicity was mild to moderate, and there were no vaccine-related serious AEs. The complete dose was consumed in 95.3% and 98.1% of vaccine and placebo recipients, respectively. PXVX0200 appears safe, immunogenic, and well tolerated in children and adolescents aged 6-17 years.


Asunto(s)
Vacunas contra el Cólera/efectos adversos , Vacunas contra el Cólera/inmunología , Cólera/prevención & control , Inmunogenicidad Vacunal , Administración Oral , Adolescente , Niño , Vacunas contra el Cólera/administración & dosificación , Método Doble Ciego , Femenino , Humanos , Masculino , Estados Unidos
11.
Biofouling ; 35(10): 1093-1103, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31825257

RESUMEN

Cholera caused by the Gram-negative bacterium Vibrio cholerae still remains a major health burden in developing countries due to its high transmissibility and multidrug resistance. Alternative strategies are in quest to curtail the disease focusing on antivirulent approaches, such as biofilm inhibition, which make bacteria more susceptible to antibiotic therapies. The biofilm state is important for V. cholerae pathogenesis and its persistence in the environment. In the present study, tryptanthrin, a phytochemical, has been identified as possessing strong anti-biofilm activity at sub MIC (2 µg ml-1) against V. cholerae. LuxO was identified as the putative target of tryptanthrin by molecular docking and real time analysis. The phytochemical was identified as safe and possessed synergistic action with ciprofloxacin, a commonly used quinolone antibiotic to treat cholera. Collectively, the study establishes the first report on the anti-biofilm property of tryptanthrin by targeting LuxO, which could serve as a potential antivirulent therapy to combat V. cholerae infections.


Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/fisiología , Biopelículas/efectos de los fármacos , Quinazolinas/farmacología , Percepción de Quorum/efectos de los fármacos , Vibrio cholerae/efectos de los fármacos , Antibacterianos/toxicidad , Proteínas Bacterianas/química , Biopelículas/crecimiento & desarrollo , Supervivencia Celular , Cólera/microbiología , Cólera/prevención & control , Células HEK293 , Humanos , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento Molecular , Quinazolinas/toxicidad , Vibrio cholerae/crecimiento & desarrollo
12.
PLoS Med ; 16(12): e1003003, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31825965

RESUMEN

BACKGROUND: Cholera causes an estimated 100,000 deaths annually worldwide, with the majority of burden reported in sub-Saharan Africa. In May 2018, the World Health Assembly committed to reducing worldwide cholera deaths by 90% by 2030. Oral cholera vaccine (OCV) plays a key role in reducing the near-term risk of cholera, although global supplies are limited. Characterizing the potential impact and cost-effectiveness of mass OCV deployment strategies is critical for setting expectations and developing cholera control plans that maximize the chances of success. METHODS AND FINDINGS: We compared the projected impacts of vaccination campaigns across sub-Saharan Africa from 2018 through 2030 when targeting geographically according to historical cholera burden and risk factors. We assessed the number of averted cases, deaths, and disability-adjusted life years and the cost-effectiveness of these campaigns with models that accounted for direct and indirect vaccine effects and population projections over time. Under current vaccine supply projections, an approach optimized to targeting by historical burden is projected to avert 828,971 (95% CI 803,370-859,980) cases (equivalent to 34.0% of projected cases; 95% CI 33.2%-34.8%). An approach that balances logistical feasibility with targeting historical burden is projected to avert 617,424 (95% CI 599,150-643,891) cases. In contrast, approaches optimized for targeting locations with limited access to water and sanitation are projected to avert 273,939 (95% CI 270,319-277,002) and 109,817 (95% CI 103,735-114,110) cases, respectively. We find that the most logistically feasible targeting strategy costs US$1,843 (95% CI 1,328-14,312) per DALY averted during this period and that effective geographic targeting of OCV campaigns can have a greater impact on cost-effectiveness than improvements to vaccine efficacy and moderate increases in coverage. Although our modeling approach does not project annual changes in baseline cholera risk or directly incorporate immunity from natural cholera infection, our estimates of the relative performance of different vaccination strategies should be robust to these factors. CONCLUSIONS: Our study suggests that geographic targeting substantially improves the cost-effectiveness and impact of oral cholera vaccination campaigns. Districts with the poorest access to improved water and sanitation are not the same as districts with the greatest historical cholera incidence. While OCV campaigns can improve cholera control in the near term, without rapid progress in developing water and sanitation services or dramatic increases in OCV supply, our results suggest that vaccine use alone is unlikely to allow us to achieve the 2030 goal.


Asunto(s)
Cólera/epidemiología , Vacunación Masiva/economía , Vacunación/economía , Administración Oral , Adulto , África del Sur del Sahara , Cólera/prevención & control , Análisis Costo-Beneficio , Femenino , Humanos , Incidencia , Vacunación Masiva/métodos , Factores de Riesgo
13.
BMC Infect Dis ; 19(1): 1075, 2019 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-31864298

RESUMEN

BACKGROUND: Cholera is a major public health concern in displaced-person camps, which often contend with overcrowding and scarcity of resources. Maela, the largest and longest-standing refugee camp in Thailand, located along the Thai-Burmese border, experienced four cholera outbreaks between 2005 and 2010. In 2013, a cholera vaccine campaign was implemented in the camp. To assist in the evaluation of the campaign and planning for subsequent campaigns, we developed a mathematical model of cholera in Maela. METHODS: We formulated a Susceptible-Infectious-Water-Recovered-based transmission model and estimated parameters using incidence data from 2010. We next evaluated the reduction in cases conferred by several immunization strategies, varying timing, effectiveness, and resources (i.e., vaccine availability). After the vaccine campaign, we generated case forecasts for the next year, to inform on-the-ground decision-making regarding whether a booster campaign was needed. RESULTS: We found that preexposure vaccination can substantially reduce the risk of cholera even when <50% of the population is given the full two-dose series. Additionally, the preferred number of doses per person should be considered in the context of one vs. two dose effectiveness and vaccine availability. For reactive vaccination, a trade-off between timing and effectiveness was revealed, indicating that it may be beneficial to give one dose to more people rather than two doses to fewer people, given that a two-dose schedule would incur a delay in administration of the second dose. Forecasting using realistic coverage levels predicted that there was no need for a booster campaign in 2014 (consistent with our predictions, there was not a cholera epidemic in 2014). CONCLUSIONS: Our analyses suggest that vaccination in conjunction with ongoing water sanitation and hygiene efforts provides an effective strategy for controlling cholera outbreaks in refugee camps. Effective preexposure vaccination depends on timing and effectiveness. If a camp is facing an outbreak, delayed distribution of vaccines can substantially alter the effectiveness of reactive vaccination, suggesting that quick distribution of vaccines may be more important than ensuring every individual receives both vaccine doses. Overall, this analysis illustrates how mathematical models can be applied in public health practice, to assist in evaluating alternative intervention strategies and inform decision-making.


Asunto(s)
Vacunas contra el Cólera/administración & dosificación , Cólera/prevención & control , Modelos Teóricos , Salud Pública/métodos , Campos de Refugiados , Vacunación/métodos , Cólera/epidemiología , Cólera/transmisión , Vacunas contra el Cólera/provisión & distribución , Brotes de Enfermedades/prevención & control , Humanos , Saneamiento , Tailandia/epidemiología
14.
Elife ; 82019 12 30.
Artículo en Inglés | MEDLINE | ID: mdl-31886768

RESUMEN

Case-area targeted interventions (CATIs) against cholera are conducted by rapid response teams, and may include various activities like water, sanitation, hygiene measures. However, their real-world effectiveness has never been established. We conducted a retrospective observational study in 2015-2017 in the Centre department of Haiti. Using cholera cases, stool cultures and CATI records, we identified 238 outbreaks that were responded to. After adjusting for potential confounders, we found that a prompt response could reduce the number of accumulated cases by 76% (95% confidence interval, 59 to 86) and the outbreak duration by 61% (41 to 75) when compared to a delayed response. An intense response could reduce the number of accumulated cases by 59% (11 to 81) and the outbreak duration by 73% (49 to 86) when compared to a weaker response. These results suggest that prompt and repeated CATIs were significantly effective at mitigating and shortening cholera outbreaks in Haiti.


Asunto(s)
Cólera/epidemiología , Microbiología del Agua , Cólera/microbiología , Cólera/prevención & control , Brotes de Enfermedades , Haití/epidemiología , Humanos , Higiene , Saneamiento , Agua/análisis
15.
Prehosp Disaster Med ; 34(5): 557-562, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31477186

RESUMEN

Disasters, such as cyclones, create conditions that increase the risk of infectious disease outbreaks. Epidemic forecasts can be valuable for targeting highest risk populations before an outbreak. The two main barriers to routine use of real-time forecasts include scientific and operational challenges. First, accuracy may be limited by availability of data and the uncertainty associated with the inherently stochastic processes that determine when and where outbreaks happen and spread. Second, even if data are available, the appropriate channels of communication may prevent their use for decision making.In April 2019, only six weeks after Cyclone Idai devastated Mozambique's central region and sparked a cholera outbreak, Cyclone Kenneth severely damaged northern areas of the country. By June 10, a total of 267 cases of cholera were confirmed, sparking a vaccination campaign. Prior to Kenneth's landfall, a team of academic researchers, humanitarian responders, and health agencies developed a simple model to forecast areas at highest risk of a cholera outbreak. The model created risk indices for each district using combinations of four metrics: (1) flooding data; (2) previous annual cholera incidence; (3) sensitivity of previous outbreaks to the El Niño-Southern Oscillation cycle; and (4) a diffusion (gravity) model to simulate movement of infected travelers. As information on cases became available, the risk model was continuously updated. A web-based tool was produced, which identified highest risk populations prior to the cyclone and the districts at-risk following the start of the outbreak.The model prior to Kenneth's arrival using the metrics of previous incidence, projected flood, and El Niño sensitivity accurately predicted areas at highest risk for cholera. Despite this success, not all data were available at the scale at which the vaccination campaign took place, limiting the model's utility, and the extent to which the forecasts were used remains unclear. Here, the science behind these forecasts and the organizational structure of this collaborative effort are discussed. The barriers to the routine use of forecasts in crisis settings are highlighted, as well as the potential for flexible teams to rapidly produce actionable insights for decision making using simple modeling tools, both before and during an outbreak.


Asunto(s)
Cólera/epidemiología , Tormentas Ciclónicas , Brotes de Enfermedades/prevención & control , Cólera/prevención & control , Demografía , Planificación en Desastres , Predicción , Humanos , Incidencia , Mozambique/epidemiología , Factores de Riesgo , Gestión de Riesgos
16.
PLoS One ; 14(8): e0219040, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31469853

RESUMEN

BACKGROUND: In April 2016, an emergency vaccination campaign using one dose of Oral Cholera Vaccine (OCV) was organized in response to a cholera outbreak that started in Lusaka in February 2016. In December 2016, a second round of vaccination was conducted, with the objective of increasing the duration of protection, before the high-risk period for cholera transmission. We assessed vaccination coverage for the first and second rounds of the OCV campaign. METHODS: Vaccination coverage was estimated after each round from a sample selected from targeted-areas for vaccination using a cross-sectional survey in to establish the vaccination status of the individuals recruited. The study population included all individuals older than 12 months residing in the areas targeted for vaccination. We interviewed 505 randomly selected individuals after the first round and 442 after the second round. Vaccination status was ascertained either by vaccination card or verbal reporting. Households were selected using spatial random sampling. RESULTS: The vaccination coverage with two doses was 58.1% (25/43; 95%CI: 42.1-72.9) in children 1-5 years old, 59.5% (69/116; 95%CI: 49.9-68.5) in children 5-15 years old and 19.9% (56/281; 95%CI: 15.4-25.1) in adults above 15 years old. The overall dropout rate was 10.9% (95%CI: 8.1-14.1). Overall, 69.9% (n = 309/442; 95%CI: 65.4-74.1) reported to have received at least one OCV dose. CONCLUSIONS: The areas at highest risk of suffering cholera outbreaks were targeted for vaccination obtaining relatively high vaccine coverage after each round. However, the long delay between doses in areas subject to considerable population movement resulted in many individuals receiving only one OCV dose. Additional vaccination campaigns may be required to sustain protection over time in case of persistence of risk. Further evidence is needed to establish a maximum optimal interval time of a delayed second dose and variations in different settings.


Asunto(s)
Vacunas contra el Cólera/administración & dosificación , Cólera/prevención & control , Cólera/transmisión , Vacunación/métodos , Administración Oral , Adolescente , Adulto , Niño , Cólera/epidemiología , Vacunas contra el Cólera/inmunología , Brotes de Enfermedades/prevención & control , Relación Dosis-Respuesta Inmunológica , Femenino , Humanos , Masculino , Riesgo , Factores de Tiempo , Adulto Joven , Zambia/epidemiología
17.
BMC Res Notes ; 12(1): 475, 2019 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-31370867

RESUMEN

OBJECTIVES: We study the transmission dynamics of cholera in the presence of limited resources, a common feature of the developing world. The model is used to gain insight into the impact of available resources of the health care system on the spread and control of the disease. A deterministic model that includes a nonlinear recovery rate is formulated and rigorously analyzed. Limited treatment is described by inclusion of a special treatment function. Center manifold theory is used to show that the model exhibits the phenomenon of backward bifurcation. Matlab has been used to carry out numerical simulations to support theoretical findings. RESULTS: The model analysis shows that the disease free steady state is locally stable when the threshold [Formula: see text]. It is also shown that the model has multiple equilibria and the model exhibits the phenomenon of backward bifurcation whose implications to cholera infection are discussed. The results are useful for the public health planning in resource allocation for the control of cholera transmission.


Asunto(s)
Cólera/prevención & control , Capacidad de Camas en Hospitales/estadística & datos numéricos , Hospitales/estadística & datos numéricos , Modelos Estadísticos , Salud Pública/estadística & datos numéricos , Cólera/economía , Cólera/epidemiología , Cólera/transmisión , Simulación por Computador , Países en Desarrollo , Humanos , Salud Pública/economía , Salud Pública/métodos , Vibrio cholerae/patogenicidad , Zimbabwe/epidemiología
18.
Hum Vaccin Immunother ; 15(12): 2882-2886, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31441679

RESUMEN

Background: The new influx of Forcibly Displaced Myanmar Nationals (FDMNs) into Bangladesh started in August 2017 through different entry points of Bangladesh. Considering the imminent threat of infectious diseases outbreaks, the Government of Bangladesh (GoB) decided to vaccinate children against three deadly diseases (measles, rubella and poliomyelitis) and oral cholera vaccine (OCV) for all except <1 year children. After completion of the campaigns, post-vaccination campaign evaluation was carried out to assess the coverage of OCV, OPV and MR vaccines during campaigns.Methods: Post-vaccination campaign evaluation was conducted after completion of the 2nd dose of oral cholera vaccine (OCV2) and oral polio vaccine (OPV2) through a cross-sectional survey. The evaluation was conducted in the Balukhali camps under Ukhiya upazilla. Precision-based sample size was calculated to estimate the vaccine coverage. Ninety-two trained interviewers were involved to collect data from the target of approximately 40000 FDMNs between 18 and 25 November 2017.Results: Data were collected from 39,438 FDMNs during the survey period. The highest coverage was observed for OCVs (94% for OCV1 and 92% for OCV2). On the other hand, lower coverage was observed for the other vaccines; the coverage for OPV1, OPV2 and MR were 75%, 88% and 38%, respectively. Unawareness (30.7% did not know about the campaign) was the most notable cause of lowering down MR vaccine coverage.Conclusion: The experience in Bangladesh demonstrates that vaccine campaigns can be successfully implemented as part of a comprehensive response toward disease outbreak among high-risk populations in humanitarian crisis.


Asunto(s)
Vacunas contra el Cólera/administración & dosificación , Vacuna Antisarampión/administración & dosificación , Vacuna Antipolio Oral/administración & dosificación , Refugiados , Vacuna contra la Rubéola/administración & dosificación , Cobertura de Vacunación/estadística & datos numéricos , Adolescente , Bangladesh , Niño , Preescolar , Cólera/prevención & control , Estudios Transversales , Brotes de Enfermedades/prevención & control , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Vacunación Masiva/estadística & datos numéricos , Sarampión/prevención & control , Mianmar , Poliomielitis/prevención & control , Rubéola (Sarampión Alemán)/prevención & control
19.
BMC Public Health ; 19(1): 1028, 2019 07 31.
Artículo en Inglés | MEDLINE | ID: mdl-31366398

RESUMEN

BACKGROUND: The Cholera-Hospital-Based-Intervention-for-7-Days (CHoBI7) is a handwashing with soap and water treatment intervention program delivered by a health promoter bedside in a health facility and through home visits to diarrhea patients and their household members during the 7 days after admission to a health facility. In a randomized controlled trial among cholera patient households in Bangladesh, the 7-day CHoBI7 program resulted in a significant reduction in cholera among household members of cholera patients and sustained improvements in drinking water quality and handwashing with soap practices 12 months post-intervention. In an effort to take this intervention to scale across Bangladesh in partnership with the Bangladesh Ministry of Health and Family Welfare, this study evaluates the feasibility and acceptability of mobile health (mHealth) programs as a low-cost, scalable approach for CHoBI7 program delivery. METHODS: Formative research for the development of the CHoBI7 mHealth intervention included 40 semi-structured interviews, 4 mHealth workshops, 2 group discussions, and a pilot study of 52 households to assess the feasibility and acceptability of the developed mHealth program. Thematic analysis of the interviews and group discussions was conducted by two individuals separately based on emergent themes, and then themes were compared and discussed. RESULTS: A theory- and evidence-based approach using qualitative research methods was implemented to design the CHoBI7 mHealth program. Semi-structured interviews with government stakeholders identified perceptions and preferences for scaling the CHoBI7 mHealth program. Group discussions and semi-structured interviews with diarrhea patients and their family members identified beneficiary perceptions of mHealth and preferences for CHoBI7 mHealth program delivery. mHealth workshops were conducted as an interactive approach to draft and refine mobile message content based on stakeholder preferences. The pilot findings indicate that the CHoBI7 mHealth program has high user acceptability and is feasible to deliver to diarrhea patients that present at health facilities for treatment in Bangladesh. Both text and voice messages were recommended for program delivery. Dr. Chobi, the sender of mHealth messages, was viewed as a credible source of information that could be shared with others. CONCLUSION: This study presents a theory- and evidence-based approach that can be implemented for the development of future water, sanitation, and hygiene mHealth programs in low-resource settings.


Asunto(s)
Cólera/prevención & control , Diarrea/terapia , Higiene/normas , Desarrollo de Programa , Saneamiento/normas , Telemedicina/organización & administración , Calidad del Agua/normas , Bangladesh , Composición Familiar , Estudios de Factibilidad , Femenino , Desinfección de las Manos , Hospitales , Humanos , Masculino , Proyectos Piloto , Investigación Cualitativa , Proyectos de Investigación , Jabones
20.
PLoS Negl Trop Dis ; 13(8): e0007634, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31369553

RESUMEN

BACKGROUND: Oral cholera vaccine (OCV) containing killed Vibrio cholerae O1 and O139 organisms (Bivalent-OCV; Biv-OCV) are playing a central role in global cholera control strategies. OCV is currently administered in a 2-dose regimen (day 0 and 14). There is a growing body of evidence that immune responses targeting the O-specific polysaccharide (OSP) of V. cholerae mediate protection against cholera. There are limited data on anti-OSP responses in recipients of Biv-OCV. We assessed serum antibody responses against O1 OSP, as well as antibody secreting cell (ASC) responses (a surrogate marker for mucosal immunity) and memory B cell responses in blood of adult recipients of Biv-OCV in Dhaka, Bangladesh. METHODOLOGY/PRINCIPAL FINDINGS: We enrolled 30 healthy adults in this study and administered two doses of OCV (Shanchol) at days 0 and 14. Blood samples were collected before vaccination (day 0) and 7 days after each vaccination (day 7 and day 21), as well as on day 44. Serum responses were largely IgA with minimal IgG and IgM responses in this population. There was no appreciable boosting following day 14 vaccination. There were significant anti-OSP IgA ASC responses on day 7 following the first vaccination, but none after the second immunization. Anti-OSP IgA memory B cell responses were detectable 30 days after completion of the vaccination series, with no evident induction of IgG memory responses. In this population, anti-Ogawa OSP responses were more prominent than anti-Inaba responses, perhaps reflecting impact of previous exposure. Serum anti-OSP responses returned to baseline within 30 days of completing the vaccine series. CONCLUSION: Our results call into question the utility of the 2-dose regimen separated by 14 days in adults in cholera endemic areas, and also suggest that Biv-OCV-induced immune responses targeting OSP are largely IgA in this highly endemic cholera area. Studies in children in cholera-endemic areas need to be performed. Protective efficacy that extends for more than a month after vaccination presumably is mediated by direct mucosal immune response which is not assessed in this study. Our results suggest a single dose of OCV in adults in a cholera endemic zone may be sufficient to mediate at least short-term protection.


Asunto(s)
Formación de Anticuerpos , Vacunas contra el Cólera/inmunología , Cólera/prevención & control , Memoria Inmunológica/inmunología , Membrana Mucosa/inmunología , Antígenos O/inmunología , Vacunación , Vibrio cholerae O1/inmunología , Administración Oral , Adolescente , Adulto , Anticuerpos Antibacterianos/sangre , Células Productoras de Anticuerpos/inmunología , Linfocitos B/inmunología , Bangladesh , Vacunas contra el Cólera/administración & dosificación , Femenino , Humanos , Inmunoglobulina A/sangre , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Masculino , Persona de Mediana Edad , Vibrio cholerae O139/inmunología , Adulto Joven
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