Showing papers on "Cholera vaccine published in 2018"
TL;DR: A single dose of the inactivated whole-cell OCV offered protection to older children and adults that was sustained for at least 2 years, and the absence of protection of young children might reflect a lesser degree of pre-existing natural immunity in this age group.
Abstract: Summary Background A single-dose regimen of inactivated whole-cell oral cholera vaccine (OCV) is attractive because it reduces logistical challenges for vaccination and could enable more people to be vaccinated. Previously, we reported the efficacy of a single dose of an OCV vaccine during the 6 months following dosing. Herein, we report the results of 2 years of follow-up. Methods In this placebo-controlled, double-blind trial done in Dhaka, Bangladesh, individuals aged 1 year or older with no history of receipt of OCV were randomly assigned to receive a single dose of inactivated OCV or oral placebo. The primary endpoint was a confirmed episode of non-bloody diarrhoea for which the onset was at least 7 days after dosing and a faecal culture was positive for Vibrio cholerae O1 or O139. Passive surveillance for diarrhoea was done in 13 hospitals or major clinics located in or near the study area for 2 years after the last administered dose. We assessed the protective efficacy of the OCV against culture-confirmed cholera occurring 7–730 days after dosing with both crude and multivariable per-protocol analyses. This trial is registered at ClinicalTrials.gov, number NCT02027207. Findings Between Jan 10, 2014, and Feb 4, 2014, 205 513 people were randomly assigned to receive either vaccine or placebo, of whom 204 700 (102 552 vaccine recipients and 102 148 placebo recipients) were included in the per-protocol analysis. 287 first episodes of cholera (109 among vaccine recipients and 178 among placebo recipients) were detected during the 2-year follow-up; 138 of these episodes (46 in vaccine recipients and 92 in placebo recipients) were associated with severe dehydration. The overall incidence rates of initial cholera episodes were 0·22 (95% CI 0·18 to 0·27) per 100 000 person-days in vaccine recipients versus 0·36 (0·31 to 0·42) per 100 000 person-days in placebo recipients (adjusted protective efficacy 39%, 95% CI 23 to 52). The overall incidence of severe cholera was 0·09 (0·07 to 0·12) per 100 000 person-days versus 0·19 (0·15 to 0·23; adjusted protective efficacy 50%, 29 to 65). Vaccine protective efficacy was 52% (8 to 75) against all cholera episodes and 71% (27 to 88) against severe cholera episodes in participants aged 5 years to younger than 15 years. For participants aged 15 years or older, vaccine protective efficacy was 59% (42 to 71) against all cholera episodes and 59% (35 to 74) against severe cholera. The protection in the older age groups was sustained throughout the 2-year follow-up. In participants younger than 5 years, the vaccine did not show protection against either all cholera episodes (protective efficacy −13%, −68 to 25) or severe cholera episodes (−44%, −220 to 35). Interpretation A single dose of the inactivated whole-cell OCV offered protection to older children and adults that was sustained for at least 2 years. The absence of protection of young children might reflect a lesser degree of pre-existing natural immunity in this age group. Funding Bill & Melinda Gates Foundation to the International Vaccine Institute.
75 citations
TL;DR: Mathematically modeling indicates that an intervention that works at the speed of HaitiV-mediated protection could improve the public health impact of reactive vaccination, and features suggest that HaitiV mediates probiotic-like protection from cholera, a mechanism that is not known to be elicited by traditional vaccines.
Abstract: Outbreaks of cholera, a rapidly fatal diarrheal disease, often spread explosively. The efficacy of reactive vaccination campaigns-deploying Vibrio cholerae vaccines during epidemics-is partially limited by the time required for vaccine recipients to develop adaptive immunity. We created HaitiV, a live attenuated cholera vaccine candidate, by deleting diarrheagenic factors from a recent clinical isolate of V. cholerae and incorporating safeguards against vaccine reversion. We demonstrate that administration of HaitiV 24 hours before lethal challenge with wild-type V. cholerae reduced intestinal colonization by the wild-type strain, slowed disease progression, and reduced mortality in an infant rabbit model of cholera. HaitiV-mediated protection required viable vaccine, and rapid protection kinetics are not consistent with development of adaptive immunity. These features suggest that HaitiV mediates probiotic-like protection from cholera, a mechanism that is not known to be elicited by traditional vaccines. Mathematical modeling indicates that an intervention that works at the speed of HaitiV-mediated protection could improve the public health impact of reactive vaccination.
60 citations
TL;DR: A multifaceted public health response that included increased chlorination of the Lusaka municipal water supply, provision of emergency water supplies, water quality monitoring and testing, enhanced surveillance, epidemiologic investigations, a cholera vaccination campaign, aggressive case management and health care worker training, and laboratory testing of clinical samples was launched.
Abstract: On October 6, 2017, an outbreak of cholera was declared in Zambia after laboratory confirmation of Vibrio cholerae O1, biotype El Tor, serotype Ogawa, from stool specimens from two patients with acute watery diarrhea. The two patients had gone to a clinic in Lusaka, the capital city, on October 4. Cholera cases increased rapidly, from several hundred cases in early December 2017 to approximately 2,000 by early January 2018 (Figure). In collaboration with partners, the Zambia Ministry of Health (MoH) launched a multifaceted public health response that included increased chlorination of the Lusaka municipal water supply, provision of emergency water supplies, water quality monitoring and testing, enhanced surveillance, epidemiologic investigations, a cholera vaccination campaign, aggressive case management and health care worker training, and laboratory testing of clinical samples. In late December 2017, a number of water-related preventive actions were initiated, including increasing chlorine levels throughout the city's water distribution system and placing emergency tanks of chlorinated water in the most affected neighborhoods; cholera cases declined sharply in January 2018. During January 10-February 14, 2018, approximately 2 million doses of oral cholera vaccine were administered to Lusaka residents aged ≥1 year. However, in mid-March, heavy flooding and widespread water shortages occurred, leading to a resurgence of cholera. As of May 12, 2018, the outbreak had affected seven of the 10 provinces in Zambia, with 5,905 suspected cases and a case fatality rate (CFR) of 1.9%. Among the suspected cases, 5,414 (91.7%), including 98 deaths (CFR = 1.8%), occurred in Lusaka residents.
50 citations
TL;DR: In a setting of epidemic and newly endemic cholera in Haiti, single-dose vaccination with killed, bivalent, whole-cell oral cholERA vaccination provided short-term protection; however, vaccination with two doses was required for long- term protection, which lasted up to 4 years after vaccination.
44 citations
TL;DR: A moderate quality of evidence suggests that HWT interventions reduce the burden of disease in cholera outbreaks and the risk of disease transmission.
Abstract: Water, sanitation, and hygiene are one part of a cholera control strategy Household water treatment (HWT) in particular has been shown to improve the microbiological quality of stored water and reduce the disease burden We conducted a systematic review of published and gray literature to determine the outcomes and impacts of HWT in preventing cholera specifically Fourteen manuscripts with 18 evaluations of HWT interventions in cholera were identified Overall, a moderate quality of evidence suggests that HWT interventions reduce the burden of disease in cholera outbreaks and the risk of disease transmission Appropriate training for users and community health worker follow-up are necessary for use Barriers to uptake include taste and odor concerns, and facilitators include prior exposure, ease of use, and links to preexisting development programming Further research on local barriers and facilitators, HWT filters, scaling up existing development programs, program sustainability, integrating HWT and oral cholera vaccine, and monitoring in low-access emergencies is recommended
44 citations
TL;DR: Oral vaccination with live attenuated cholera vaccine CVD 103-HgR induces antibodies that target V. cholerae OSP, and these anti-OSP responses correlate with protection against diarrhea following experimental challenge with V. Cholera O1.
Abstract: Background Cholera is an acute voluminous dehydrating diarrheal disease caused by toxigenic strains of Vibrio cholerae O1 and occasionally O139. A growing body of evidence indicates that immune responses targeting the O-specific polysaccharide (OSP) of V. cholerae are involved in mediating protection against cholera. We therefore assessed whether antibody responses against OSP occur after vaccination with live attenuated oral cholera vaccine CVD 103-HgR, and whether such responses correlate with protection against cholera. Methodology We assessed adult North American volunteers (n = 46) who were vaccinated with 5 × 108 colony-forming units (CFU) of oral cholera vaccine CVD 103-HgR and then orally challenged with approximately 1 × 105 CFU of wild-type V. cholerae O1 El Tor Inaba strain N16961, either 10 or 90 days post-vaccination. Principal findings Vaccination was associated with induction of significant serum IgM and IgA anti-OSP and vibriocidal antibody responses within 10 days of vaccination. There was significant correlation between anti-OSP and vibriocidal antibody responses. IgM and IgA anti-OSP responses on day 10 following vaccination were associated with lower post-challenge stool volume (r = −0.44, P = 0.002; r = −0.36, P = 0.01; respectively), and none of 27 vaccinees who developed a ≥1.5 fold increase in any antibody isotype targeting OSP on day 10 following vaccination compared to baseline developed moderate or severe cholera following experimental challenge, while 5 of 19 who did not develop such anti-OSP responses did (P = 0.01). Conclusion Oral vaccination with live attenuated cholera vaccine CVD 103-HgR induces antibodies that target V. cholerae OSP, and these anti-OSP responses correlate with protection against diarrhea following experimental challenge with V. cholerae O1. Trial registration ClinicalTrials.gov NCT01895855
34 citations
TL;DR: It is found that an early and large-scale targeted reactive campaign using a single-dose oral vaccine, organized in response to a cholera epidemic within a large city, to be feasible and appeared effective.
Abstract: Objective To describe the implementation and feasibility of an innovative mass vaccination strategy - based on single-dose oral cholera vaccine - to curb a cholera epidemic in a large urban setting. Method In April 2016, in the early stages of a cholera outbreak in Lusaka, Zambia, the health ministry collaborated with Medecins Sans Frontieres and the World Health Organization in organizing a mass vaccination campaign, based on single-dose oral cholera vaccine. Over a period of 17 days, partners mobilized 1700 health ministry staff and community volunteers for community sensitization, social mobilization and vaccination activities in 10 townships. On each day, doses of vaccine were delivered to vaccination sites and administrative coverage was estimated. Findings Overall, vaccination teams administered 424 100 doses of vaccine to an estimated target population of 578 043, resulting in an estimated administrative coverage of 73.4%. After the campaign, few cholera cases were reported and there was no evidence of the disease spreading within the vaccinated areas. The total cost of the campaign - 2.31 United States dollars (US$) per dose - included the relatively low cost of local delivery - US$ 0.41 per dose. Conclusion We found that an early and large-scale targeted reactive campaign using a single-dose oral vaccine, organized in response to a cholera epidemic within a large city, to be feasible and appeared effective. While cholera vaccines remain in short supply, the maximization of the number of vaccines in response to a cholera epidemic, by the use of just one dose per member of an at-risk community, should be considered.
34 citations
TL;DR: It is shown that vaccination may be best targeted at populations with intermediate degrees of mobility as compared to communities with very high or very low population turnover, and a community could be protected longer by a blended “Mass and Maintain” strategy.
Abstract: Background
Oral cholera vaccination is an approach to preventing outbreaks in at-risk settings and controlling cholera in endemic settings. However, vaccine-derived herd immunity may be short-lived due to interactions between human mobility and imperfect or waning vaccine efficacy. As the supply and utilization of oral cholera vaccines grows, critical questions related to herd immunity are emerging, including: who should be targeted; when should revaccination be performed; and why have cholera outbreaks occurred in recently vaccinated populations?
Methods and findings
We use mathematical models to simulate routine and mass oral cholera vaccination in populations with varying degrees of migration, transmission intensity, and vaccine coverage. We show that migration and waning vaccine efficacy strongly influence the duration of herd immunity while birth and death rates have relatively minimal impacts. As compared to either periodic mass vaccination or routine vaccination alone, a community could be protected longer by a blended “Mass and Maintain” strategy. We show that vaccination may be best targeted at populations with intermediate degrees of mobility as compared to communities with very high or very low population turnover. Using a case study of an internally displaced person camp in South Sudan which underwent high-coverage mass vaccination in 2014 and 2015, we show that waning vaccine direct effects and high population turnover rendered the camp over 80% susceptible at the time of the cholera outbreak beginning in October 2016.
Conclusions
Oral cholera vaccines can be powerful tools for quickly protecting a population for a period of time that depends critically on vaccine coverage, vaccine efficacy over time, and the rate of population turnover through human mobility. Due to waning herd immunity, epidemics in vaccinated communities are possible but become less likely through complementary interventions or data-driven revaccination strategies.
28 citations
TL;DR: Oral cholera vaccination induces antigen-specific MBC responses, and the anamnestic LPS-specific responses may contribute to long-term protection and provide correlates of the duration of vaccine-induced protection.
27 citations
TL;DR: Administration of the cholera vaccine after CRC diagnosis is associated with decreased risk of death from CRC and overall mortality, and the decrease in mortality was largely observed, irrespective of patient age or tumor stage at diagnosis or sex.
TL;DR: The study demonstrates that mass cholera vaccination administered through the public health system in Ethiopia is feasible, can be implemented through the existing health system at an affordable cost, and the vaccine is acceptable to the community.
Abstract: Shanchol™, a WHO-prequalified oral cholera vaccine (OCV), has been used to control endemic cholera in Asia, as well as in emergencies and outbreaks elsewhere. The vaccine has not been used by public health systems in cholera-endemic settings of Africa although several outbreak response campaigns have been conducted. Here we present experiences from a mass vaccination campaign in a cholera-endemic setting of Ethiopia in which Shanchol™ was introduced through the public health system. The vaccination site was selected based on cholera cases reported in previous years. Social mobilization involved sensitization of community leaders, household visits, and mass distribution of banners, posters and leaflets. The vaccination was implemented after careful microplanning of logistics and cold chain, manpower, transportation, vaccine supply and supervision and monitoring of adverse events. Vaccine administration was recorded on individual vaccination cards. Vaccine delivery costs were collected and analyzed after vaccination. As there was no experience with Shanchol™ in Ethiopia, a bridging trial was conducted to demonstrate safety and immunogenicity of the vaccine in the local population prior to the mass vaccination. Oral cholera vaccination was conducted in two rounds of four days each in February 2015 and March 2015 in 10 selected villages of Shashemenae rural district of Ethiopia. A total of 62,161 people targeted. 47,137 people (76%) received the first dose, and 40,707 (65%) received two doses. The financial cost of the vaccination campaign was estimated at US $2·60 per dose or US $5·64 per fully immunized person. The cost of vaccine delivery excluding vaccine procurement was $0·68 per dose or $1·48 per fully immunized person. The study demonstrates that mass cholera vaccination administered through the public health system in Ethiopia is feasible, can be implemented through the existing health system at an affordable cost, and the vaccine is acceptable to the community. The lessons from this study are useful for deploying OCV in other African endemic settings through the public health system and may guide future immunization policy decisions.
TL;DR: Cholera vaccination campaigns using highly targeted strategies are feasible in urban settings and high vaccination coverage can be obtained using door to door vaccination, however, alternative strategies should be considered to reach non- vaccinated populations like male adults and also in order to improve the efficiency of the interventions.
Abstract: Introduction Oral cholera vaccines are primarily recommended by the World Health Organization for cholera control in endemic countries. However, the number of cholera vaccines currently produced is very limited and examples of OCV use in endemic countries, and especially in urban settings, are scarce. A vaccination campaign was organized by Medecins Sans Frontieres and the Ministry of Health in a highly endemic area in the Democratic Republic of Congo. This study aims to describe the vaccine coverage achieved with this highly targeted vaccination campaign and the acceptability among the vaccinated communities. Methods and findings We performed a cross-sectional survey using random spatial sampling. The study population included individuals one year old and above, eligible for vaccination, and residing in the areas targeted for vaccination in the city of Kalemie. Data sources were household interviews with verification by vaccination card. In total 2,488 people were included in the survey. Overall, 81.9% (95%CI: 77.9–85.3) of the target population received at least one dose of vaccine. The vaccine coverage with two doses was 67.2% (95%CI: 61.9–72.0) among the target population. The vaccine coverage was higher during the first round (74.0, 95%CI: 69.3–78.3) than during the second round of vaccination (69.1%, 95%CI: 63.9–74.0). Vaccination coverage was lower in male adults. The main reason for non-vaccination was to be absent during the campaign. No severe adverse events were notified during the interviews. Conclusions Cholera vaccination campaigns using highly targeted strategies are feasible in urban settings. High vaccination coverage can be obtained using door to door vaccination. However, alternative strategies should be considered to reach non-vaccinated populations like male adults and also in order to improve the efficiency of the interventions.
Save the Children1, UNICEF2, Ministry of Health (Malaysia)3, Ministry of Health (Cambodia)4, International Vaccine Institute5, Kathmandu6, International Centre for Diarrhoeal Disease Research, Bangladesh7, Translational Health Science and Technology Institute8, PATH9, Pasteur Institute10, World Health Organization11
TL;DR: The country situation, gaps identified in terms of cholera prevention and control and strategic interventions to bridge these gaps are reported on.
Abstract: Cholera remains a major public health problem in many countries. Poor sanitation and inappropriate clean water supply, insufficient health literacy and community mobilization, absence of national plans and cross-border collaborations are major factors impeding optimal control of cholera in endemic countries. In March 2017, a group of experts from 10 Asian cholera-prone countries that belong to the Initiative against Diarrheal and Enteric Diseases in Africa and Asia (IDEA), together with representatives from the World Health Organization, the US National Institutes of Health, International Vaccine Institute, Agence de medecine preventive, NGOs (Save the Children) and UNICEF, met in Hanoi (Vietnam) to share progress in terms of prevention and control interventions on water, sanitation and hygiene (WASH), surveillance and oral cholera vaccine use. This paper reports on the country situation, gaps identified in terms of cholera prevention and control and strategic interventions to bridge these gaps.
TL;DR: It is reported that patients in Sweden, who were diagnosed with prostate cancer between July 2005 and December 2014 and used cholera vaccine, have a decreased risk of death from prostate cancer and a decreased mortality rate, irrespective of patients’ age or tumor stage at diagnosis.
Abstract: Recent evidence suggests that cholera toxin might have multiple functions regarding the ability to regulate the immune system. However, it is unknown whether subsequent administration of cholera vaccine might affect the mortality rate in patients with prostate cancer. Here we report that patients in Sweden, who were diagnosed with prostate cancer between July 2005 and December 2014 and used cholera vaccine, have a decreased risk of death from prostate cancer (HR, 0.57; 95% CI, 0.40-0.82) as compared to patients with prostate cancer but without cholera vaccine use, adjusted for a range of confounding factors. In addition, patients using cholera vaccine show a decreased risk of death overall (HR, 0.53; 95% CI, 0.41-0.69). The decreased mortality rate is largely consistent, irrespective of patients' age or tumor stage at diagnosis. In this population-based study, we suggest that subsequent administration of cholera vaccine after prostate cancer diagnosis might reduce the mortality rate.
TL;DR: There is a need for an oral cholera vaccine to be introduced and strategies and interventions relating to water, sanitation, and hygiene, to be initiated by the Ministry of Health, with component activities that are culturally tailored to Ghanaian communities.
Abstract: Ranked among the world’s dirtiest countries, Ghana has poor environmental sanitation and hygiene, and a lack of potable water, all of which combined have been largely blamed as the underscoring reasons for cholera outbreaks. The country has concomitantly suffered seasonal cholera outbreaks that have impacted negatively on the population’s health, as well as on the nation’s economy. To prevent cyclical cholera outbreaks in Ghana, this commentary discusses the associated problems and makes recommendations to solve them. This commentary aims to throw light on the menace of cholera in Ghana and the need to curb the recurrence of outbreaks and bouts of this epidemic. Response measures, challenges, and lessons learnt from the most recent cholera outbreak are critically assessed to determine how best this public health issue could be resolved. General and specific policy recommendations are identified in this regard. To resolve this problem, there is a need for an oral cholera vaccine to be introduced. There is also a need to develop strategies and interventions relating to water, sanitation, and hygiene, to be initiated by the Ministry of Health, with component activities that are culturally tailored to Ghanaian communities. Policy change towards the prevention of outbreaks in Ghana is identified as another requisite.
TL;DR: OCV vaccination is likely to be cost-effective when targeted at the population with high-risk of cholera and poor access to health care facilities when herd protection effect is incorporated and OCV price is low.
Abstract: World Health Organization recommends oral cholera vaccine (OCV) to prevent and control cholera, but requires cost-effectiveness evidence. This review aimed to provide a critical appraisal and summary of global economic evaluation (EE) studies involving OCV to guide future EE study. Full EE studies, published from inception to December 2015, evaluating OCV against cholera disease were included. The included studies were appraised using WHO guide for standardization of EE of immunization programs. Out of 14 included studies, almost all (13/14) were in low- and middle-income countries. Most studies (11/14) evaluated mass vaccination program. Most of the studies (9/14) incorporated herd protective effect. The most common influential parameters were cholera incidence, OCV coverage, herd protection and OCV price. OCV vaccination is likely to be cost-effective when targeted at the population with high-risk of cholera and poor access to health care facilities when herd protection effect is incorporated and OCV price is low.
TL;DR: A positive association was demonstrated between the reactive use of OCVs and protection against cholera outbreaks and supported the WHO recommendation to utilize OCVs reactively as an additional measure to the standard cholERA epidemic response package.
Abstract: Introduction The efficacy of oral cholera vaccines (OCVs) in laboratory conditions has been established, and the World Health Organization (WHO; Geneva, Switzerland) has recommended their preventative use in high-risk settings. The WHO recommendation has not been fully operationalized, nor has it been extended to apply to the reactive use of OCVs in real field epidemic conditions due to concerns about potential resource diversion, feasibility, cost, and acceptability. The purpose of this study is to assess and synthesize existing evidence of OCV effectiveness when used reactively in real field conditions. Methods A systematic review and meta-analysis was conducted involving studies that investigated vaccine effectiveness when used as a reactive measure; that is, cases had reached epidemic threshold and a cholera epidemic was declared in real field epidemic conditions. OVID Medline (US National Library of Medicine, National Institutes of Health; Bethesda, Maryland USA), CINAHL (EBSCO Information Services; Ipswich, Massachusetts USA), and EMBASE (Elsevier; Amsterdam, Netherlands), along with grey literature, were systematically searched using pre-determined criteria. Two independent reviewers identified studies that met the selection criteria and data were extracted using validated tools. Pooled estimates were obtained using fixed effect models. Results Of the 347 articles that met the inclusion criteria, four studies were retrieved for meta-analysis (three were case-control studies and one was a case-cohort study) involving a total of 1,509 participants and comprising 175 cases and 1,334 case controls. The effectiveness of one or two doses of either Shanchol (Shantha Biotechnics; India) or ORC-Vax (Vabiotech; Vietnam) OCVs showed a combined vaccine effectiveness of 75% (95% CI, 61-84). Conclusion A positive association was demonstrated between the reactive use of OCVs and protection against cholera. This supported the WHO recommendation to utilize OCVs reactively as an additional measure to the standard cholera epidemic response package. Schwerdtle P , Onekon CK , Recoche K . A Quantitative Systematic Review and Meta-Analysis of the Effectiveness of Oral Cholera Vaccine as a Reactive Measure in Cholera Outbreaks. Prehosp Disaster Med. 2018;33(1):2–6.
TL;DR: Re-analyzing data from a previously published cluster-randomized, double-blind, placebo controlled trial with five years of follow-up detected a statistically significant difference in OCV efficacy when the vaccine was administered to children under 5 years old vs. children 5 years and older.
Abstract: Oral cholera vaccine (OCV) is a feasible tool to prevent or mitigate cholera outbreaks. A better understanding of the vaccine’s efficacy among different age groups and how rapidly its protection wanes could help guide vaccination policy. To estimate the level and duration of OCV efficacy, we re-analyzed data from a previously published cluster-randomized, double-blind, placebo controlled trial with five years of follow-up. We used a Cox proportional hazards model and modeled the potentially time-dependent effect of age categories on both vaccine efficacy and risk of infection in the placebo group. In addition, we investigated the impact of an outbreak period on model estimation. Vaccine efficacy was 38% (95% CI: -2%,62%) for those vaccinated from ages 1 to under 5 years old, 85% (95% CI: 67%,93%) for those 5 to under 15 years, and 69% (95% CI: 49%,81%) for those vaccinated at ages 15 years and older. Among adult vaccinees, efficacy did not appear to wane during the trial, but there was insufficient data to assess the waning of efficacy among child vaccinees. Through this re-analysis we were able to detect a statistically significant difference in OCV efficacy when the vaccine was administered to children under 5 years old vs. children 5 years and older. The estimated efficacies are more similar to the previously published analysis based on the first two years of follow-up than the analysis based on all five years. ClinicalTrials.gov identifier NCT00289224
TL;DR: The use of the ring vaccinations in general and specifically during cholera outbreaks are reviewed, which could be considered before, after or as an alternative to a mass vaccination approach.
Abstract: Ring vaccinations create a zone of immune contacts around a case to prevent further disease transmission and have been successfully employed in the eradication of smallpox and the control of other ...
TL;DR: The CtxB is a suitable immunogen of V. cholera to be incorporated in both protective and preventive vaccines and it may be used as a carrier for vaccine delivery.
TL;DR: In a Perspective, Lorenz von Seidlein and Jacqueline L. Deen discuss the implications of Andrew Azman and colleagues' accompanying study for management of cholera outbreaks.
Abstract: In a Perspective, Lorenz von Seidlein and Jacqueline L. Deen discuss the implications of Andrew Azman and colleagues' accompanying study for management of cholera outbreaks.
TL;DR: Use of the GIS facilitated designing improved vaccination strategy in a large clinical trial and vaccine uptake was significantly higher among females and among younger subjects.
TL;DR: It is found that a single-dose regimen has high short-term effectiveness, making rapid delivery of vaccine during outbreaks easier, especially given the on-going global vaccine shortage.
Abstract: The use of oral cholera vaccine (OCV) has increased since 2011, when Shanchol, the first OCV suitable for large-scale use, became available. Medecins Sans Frontieres considers OCVs an essential cholera outbreak control tool and has contributed to generating new evidence on OCV use in outbreaks. We showed that large-scale mass campaigns are feasible during outbreaks, documented high short-term effectiveness and showed that vaccines are likely safe in pregnancy. We found that a single-dose regimen has high short-term effectiveness, making rapid delivery of vaccine during outbreaks easier, especially given the on-going global vaccine shortage. Despite progress, OCV has still not been used widely in some of the largest recent outbreaks and thousands of cholera deaths are reported every year. While working towards improving our tools to protect those most at-risk of cholera, we must strive to use all available effective interventions in efficient ways, including OCV, to prevent avoidable deaths today.
TL;DR: It is suggested that TM-free Euvichol could provide comparable immunogenicity to the WHO prequalified EUVichol containing TM as it was later confirmed in a clinical study.
Abstract: Purpose An oral cholera vaccine (OCV), Euvichol, with thimerosal (TM) as preservative, was prequalified by the World Health Organization (WHO) in 2015. In recent years, public health services and regulatory bodies recommended to eliminate TM in vaccines due to theoretical safety concerns. In this study, we examined whether TM-free Euvichol induces comparable immunogenicity to its TM-containing formulation in animal model. Materials and methods To evaluate and compare the immunogenicity of the two variations of OCV, mice were immunized with TM-free or TM-containing Euvichol twice at 2-week interval by intranasal or oral route. One week after the last immunization, mice were challenged with Vibrio cholerae O1 and daily monitored to examine the protective immunity against cholera infection. In addition, serum samples were obtained from mice to measure vibriocidal activity and vaccine-specific IgG, IgM, and IgA antibodies using vibriocidal assay and enzyme-linked immunosorbent assay, respectively. Results No significant difference in immunogenicity, including vibriocidal activity and vaccine-specific IgG, IgM, and IgA in serum, was observed between mice groups administered with TM-free and -containing Euvichol, regardless of immunization route. However, intranasally immunized mice elicited higher levels of serum antibodies than those immunized via oral route. Moreover, intranasal immunization completely protected mice against V. cholerae challenge but not oral immunization. There was no significant difference in protection between two Euvichol variations. Conclusion These results suggested that TM-free Euvichol could provide comparable immunogenicity to the WHO prequalified Euvichol containing TM as it was later confirmed in a clinical study. The pulmonary mouse cholera model can be considered useful to examine in vivo the potency of OCVs.
26 Mar 2018
TL;DR: The review outlines the main historical stages in the development of cholera vaccines: parenteral, chemical, inactivated and live oral vaccines and compares active ingredients and excipients used in Dukoral®, mORC-VAX®, Shanchol®, Euvichol®, Vaxchora®, Oravacs® and the cholERA bivalent chemical vaccine.
Abstract: Cholera is an acute diarrheal disease caused by toxigenic strains of Vibrio cholerae O1 and O139 serogroups. It still remains a major global healthcare problem. According to WHO, about 100,000 people die from cholera every year, despite the modern methods of treatment, improvement in the quality of drinking water, sanitation and hygiene. In recent years, oral cholera vaccines have proved an effective tool for preventing and curbing cholera epidemics. According to the WHO Ending Cholera — A Global Roadmap, mass vaccination should help reduce the mortality resulting from cholera by 90 % worldwide by 2030 and eliminate the disease in 20 countries. The review outlines the main historical stages in the development of cholera vaccines: parenteral, chemical, inactivated and live oral vaccines. The paper compares active ingredients and excipients used in Dukoral®, mORC-VAX®, Shanchol®, Euvichol®, Vaxchora®, Oravacs® and the cholera bivalent chemical vaccine. The results of international multicenter clinical trials of oral inactivated, live and chemical cholera vaccines are analysed. Issues related to efficacy and safety studies of cholera vaccines are considered.
TL;DR: This could be a pivotal year in the fight against cholera, public health experts say, as an emergency vaccine stockpile established in 2013 has grown rapidly and a new, easier-to-use formulation has hit the market, making large-scale campaigns feasible.
Abstract: This could be a pivotal year in the fight against cholera, public health experts say The disease has taken a large toll in the last months: In war-torn Yemen the number of cases reached more than a million; outbreaks ravaged South Sudan, Tanzania, Zambia, and other African countries; and Haiti continues to suffer from the disease But an emergency vaccine stockpile established in 2013 has grown rapidly and a new, easier-to-use formulation has hit the market, making large-scale campaigns feasible Soon, 24 million doses are to be shipped to Kinshasa, the capital of the Democratic Republic of the Congo, where another epidemic looms With interventions like this, experts hope to make a dent in the global burden of cholera, estimated at 3 million cases a year And Gavi, the Vaccine Alliance, which is funding the stockpile, is set to decide later this year whether it will start funding routine immunizations in endemic areas as well
20 Feb 2018
TL;DR: The threat of cholera spread beyond the borders of endemic countries and the realness of the emergence of introduced epidemic foci remain the actual problems and neccessitate continuous development of specific prophylaxis of this disease.
Abstract: The threat of cholera spread beyond the borders of endemic countries and the realness of the emergence of introduced epidemic foci remain the actual problems and neccessitate continuous development of specific prophylaxis of this disease. The review is dedicated to the analysis of the effectiveness of licensed cholera vaccines as well as to possible perspectives of the advancement of cholera specific prophylaxis.