Abstract: BackgroundA single-dose regimen of the current killed oral cholera vaccines that have been prequalified by the World Health Organization would make them more attractive for use against endemic and epidemic cholera. We conducted an efficacy trial of a single dose of the killed oral cholera vaccine Shanchol, which is currently given in a two-dose schedule, in an urban area in which cholera is highly endemic. MethodsNonpregnant residents of Dhaka, Bangladesh, who were 1 year of age or older were randomly assigned to receive a single dose of oral cholera vaccine or oral placebo. The primary outcome was vaccine protective efficacy against culture-confirmed cholera occurring 7 to 180 days after dosing. Prespecified secondary outcomes included protective efficacy against severely dehydrating culture-confirmed cholera during the same interval, against cholera and severe cholera occurring 7 to 90 versus 91 to 180 days after dosing, and against cholera and severe cholera according to age at baseline. ResultsA total...

Abstract: Background : Cholera remains a serious public health threat in Asia, Africa and in parts of the Americas Three World health Organization (WHO) pre-qualified oral cholera vaccines are now available but their supply is limited, so current supplies must be administered strategically This requires an improved understanding of disease transmission and control strategies Methods : We used demographics and disease surveillance data collected from 1991 to 2000 in Matlab, Bangladesh, to estimate the spatial and temporal extent of the zone of increased risk around cholera cases Specifically, we compare the cholera incidence among individuals living close to cholera cases with that among individuals living close to those without medically-attended cholera in this rural endemic setting Results : Those living within 50 m of a confirmed cholera case had 36 times (95% confidence interval: 23-56) the risk of becoming a cholera case in the first 3 days (after case presentation) compared with risk elsewhere in the community The relative risk gradually declined in space and time, but remained significantly high up to 450 me away within 3 days of case presentation, and up to 150 m away within 23 days from the date of presentation of the case Conclusion : These findings suggest that, if conducted rapidly, vaccinating individuals living close to a case (ring vaccination) could be an efficient and effective strategy to target vaccine to a high-risk population in an endemic setting

Abstract: Introduction Vaccinating a buffer of individuals around a case (ring vaccination) has the potential to target those who are at highest risk of infection, reducing the number of doses needed to control a disease. We explored the potential vaccine effectiveness (VE) of oral cholera vaccines (OCVs) for such a strategy. Methods and Findings This analysis uses existing data from a cluster-randomized clinical trial in which OCV or placebo was given to 71,900 participants in Kolkata, India, from 27 July to 10 September 2006. Cholera surveillance was then conducted on 144,106 individuals living in the study area, including trial participants, for 5 y following vaccination. First, we explored the risk of cholera among contacts of cholera patients, and, second, we measured VE among individuals living within 25 m of cholera cases between 8 and 28 d after onset of the index case. For the first analysis, individuals living around each index case identified during the 5-y period were assembled using a ring to define cohorts of individuals exposed to cholera index cases. An index control without cholera was randomly selected for each index case from the same population, matched by age group, and individuals living around each index control were assembled using a ring to define cohorts not exposed to cholera cases. Cholera attack rates among the exposed and non-exposed cohorts were compared using different distances from the index case/control to define the rings and different time frames to define the period at risk. For the VE analysis, the exposed cohorts were further stratified according to the level of vaccine coverage into high and low coverage strata. Overall VE was assessed by comparing the attack rates between high and low vaccine coverage strata irrespective of individuals’ vaccination status, and indirect VE was assessed by comparing the attack rates among unvaccinated members between high and low vaccine coverage strata. Cholera risk among the cohort exposed to cholera cases was 5–11 times higher than that among the cohort not exposed to cholera cases. The risk gradually diminished with an increase in distance and time. The overall and indirect VE measured between 8 and 28 d after exposure to a cholera index case during the first 2 y was 91% (95% CI 62%–98%) and 93% (95% CI 44%–99%), respectively. VE persisted for 5 y after vaccination and was similar whether the index case was a young child (<5 y) or was older. Of note, this study was a reanalysis of a cholera vaccine trial that used two doses; thus, a limitation of the study relates to the assumption that a single dose, if administered quickly, will induce a similar level of total and indirect protection over the short term as did two doses. Conclusions These findings suggest that high-level protection can be achieved if individuals living close to cholera cases are living in a high coverage ring. Since this was an observational study including participants who had received two doses of vaccine (or placebo) in the clinical trial, further studies are needed to determine whether a ring vaccination strategy, in which vaccine is given quickly to those living close to a case, is feasible and effective. Trial registration ClinicalTrials.gov NCT00289224

Abstract: The first oral cholera vaccine (OCV) campaign, since its prequalification by the World Health Organization, in response to an ongoing cholera epidemic (reactive vaccination) was successfully conducted in a poor urban slum of approximately 70,000 inhabitants in Port-au-Prince, Haiti, in 2012. Vaccine coverage was 75% of the target population. This report documents the impact of OCV in reducing the number of culture-confirmed cases of cholera admitted to the Groupe Haitien d'Etude du Sarcome de Kaposi et des Infections Opportunistes (GHESKIO) cholera treatment center from that community in the 37 months postvaccination (April 2012-April 30, 2015). Of 1,788 patients with culture-confirmed cholera, 1,770 (99%) were either from outside the vaccine area (1,400 cases) or from the vaccinated community who had not received OCV (370 cases). Of the 388 people from the catchment area who developed culture-confirmed cholera, 370 occurred among the 17,643 people who had not been vaccinated (2.1%) and the remaining 18 occurred among the 52,357 people (0.034%) who had been vaccinated (P < 0.001), for an efficacy that approximates 97.5%. Despite not being designed as a randomized control trial, the very high efficacy is a strong evidence for the effectiveness of OCV as part of an integrated package for the control of cholera in outbreak settings.

Abstract: Environmental enteropathy (EE) is a poorly understood condition that refers to chronic alterations in intestinal permeability, absorption, and inflammation, which mainly affects young children in resource-limited settings. Recently, EE has been linked to suboptimal oral vaccine responses in children, although immunological mechanisms are poorly defined. The objective of this study was to determine host factors associated with immune responses to an oral cholera vaccine (OCV). We measured antibody and memory T cell immune responses to cholera antigens, micronutrient markers in blood, and EE markers in blood and stool from 40 Bangladeshi children aged 3–14 years who received two doses of OCV given 14 days apart. EE markers included stool myeloperoxidase (MPO) and alpha anti-trypsin (AAT), and plasma endotoxin core antibody (EndoCab), intestinal fatty acid binding protein (i-FABP), and soluble CD14 (sCD14). We used multiple linear regression analysis with LASSO regularization to identify host factors, including EE markers, micronutrient (nutritional) status, age, and HAZ score, predictive for each response of interest. We found stool MPO to be positively associated with IgG antibody responses to the B subunit of cholera toxin (P = 0.03) and IgA responses to LPS (P = 0.02); plasma sCD14 to be positively associated with LPS IgG responses (P = 0.07); plasma i-FABP to be positively associated with LPS IgG responses (P = 0.01) and with memory T cell responses specific to cholera toxin (P = 0.01); stool AAT to be negatively associated with IL-10 (regulatory) T cell responses specific to cholera toxin (P = 0.02), and plasma EndoCab to be negatively associated with cholera toxin-specific memory T cell responses (P = 0.02). In summary, in a cohort of children 3–14 years old, we demonstrated that the majority of biomarkers of environmental enteropathy were positively associated with immune responses after vaccination with an OCV.

Abstract: Introduction: Despite some improvement in provision of safe drinking water, proper sanitation and hygiene promotion, cholera still remains a major public health problem in Malawi with outbreaks occurring almost every year since 1998. In response to 2014/2015 cholera outbreak, ministry of health and partners made a decision to assess the feasibility and acceptability of conducting a mass oral cholera vaccine (OCV) as an additional public health measure. This paper highlights the burden of the 2014/15 cholera outbreak, successes and challenges of OCV campaign conducted in March and April 2015. Methods: This was a documentation of the first OCV campaign conducted in Malawi. The campaign targeted over 160,000 people aged one year or more living in 19 camps of people internally displaced by floods and their surrounding communities in Nsanje district. It was a reactive campaign as additional measure to improved water, sanitation and hygiene in response to the laboratory confirmed cholera outbreak. Results: During the first round of the OCV campaign conducted from 30 March to 4 April 2015, a total of 156,592 (97.6%) people out of 160,482 target population received OCV. During the second round (20 to 25 April 2015), a total of 137,629 (85.8%) people received OCV. Of these, 108,247 (67.6%) people received their second dose while 29,382 (18.3%) were their first dose. Of the 134,836 people with known gender and sex who received 1 or 2 doses, 54.4% were females and over half (55.4%) were children under the age of 15 years. Among 108,237 people who received 2 doses (fully immunized), 54.4% were females and 51.9% were children under 15 years of age. No severe adverse event following immunization was reported. The main reason for non-vaccination or failure to take the 2 doses was absence during the period of the campaign. Conclusion: This documentation has demonstrated that it was feasible, acceptable by the community to conduct a largescale mass OCV campaign in Malawi within five weeks. Of 320,000 OCV doses received, Malawi managed to administer at least 294,221 (91.9%) of the doses. OCV could therefore be considered to be introduced as additional measure in cholera hot spot areas in Malawi. Pan African Medical Journal 2016; 23

Abstract: Managing the dynamics of vaccine supply and demand represents a significant challenge with very high stakes. Insufficient vaccine supplies can necessitate rationing, lead to preventable adverse health outcomes, delay the achievements of elimination or eradication goals, and/or pose reputation risks for public health authorities and/or manufacturers. This article explores the dynamics of global vaccine supply and demand to consider the opportunities to develop and maintain optimal global vaccine stockpiles for universal vaccines, characterized by large global demand (for which we use measles vaccines as an example), and nonuniversal (including new and niche) vaccines (for which we use oral cholera vaccine as an example). We contrast our approach with other vaccine stockpile optimization frameworks previously developed for the United States pediatric vaccine stockpile to address disruptions in supply and global emergency response vaccine stockpiles to provide on-demand vaccines for use in outbreaks. For measles vaccine, we explore the complexity that arises due to different formulations and presentations of vaccines, consideration of rubella, and the context of regional elimination goals. We conclude that global health policy leaders and stakeholders should procure and maintain appropriate global vaccine rotating stocks for measles and rubella vaccine now to support current regional elimination goals, and should probably also do so for other vaccines to help prevent and control endemic or epidemic diseases. This work suggests the need to better model global vaccine supplies to improve efficiency in the vaccine supply chain, ensure adequate supplies to support elimination and eradication initiatives, and support progress toward the goals of the Global Vaccine Action Plan.

Abstract: Oral cholera vaccines (OCVs) are relatively new public health interventions, and limited data exist on the potential impact of OCV use on traditional cholera prevention and control measures-safe water, sanitation and hygiene (WaSH). To assess OCV acceptability and knowledge, attitudes, and practices (KAPs) regarding cholera and WaSH, we conducted cross-sectional surveys, 1 month before (baseline) and 3 and 12 months after (first and second follow-up) a preemptive OCV campaign in Maela, a long-standing refugee camp on the Thailand-Burma border. We randomly selected households for the surveys, and administered questionnaires to female heads of households. In total, 271 (77%), 187 (81%), and 199 (85%) households were included in the baseline, first and second follow-up surveys, respectively. Anticipated OCV acceptability was 97% at baseline, and 91% and 85% of household members were reported to have received 1 and 2 OCV doses at first follow-up. Compared with baseline, statistically significant differences (95% Wald confidence interval not overlapping zero) were noted at first and second follow-up among the proportions of respondents who correctly identified two or more means of cholera prevention (62% versus 78% and 80%), reported boiling or treating drinking water (19% versus 44% and 69%), and washing hands with soap (66% versus 77% and 85%); a significant difference was also observed in the proportion of households with soap available at handwashing areas (84% versus 90% and 95%), consistent with reported behaviors. No significant difference was noted in the proportion of households testing positive for Escherichia coli in stored household drinking water at second follow-up (39% versus 49% and 34%). Overall, we observed some positive, and no negative changes in cholera- and WaSH-related KAPs after an OCV campaign in Maela refugee camp. OCV campaigns may provide opportunities to reinforce beneficial WaSH-related KAPs for comprehensive cholera prevention and control.

Abstract: Despite recent large-scale cholera outbreaks, little is known about the immunogenicity of oral cholera vaccines (OCV) in African populations, particularly among those at highest cholera risk. During a 2015 preemptive OCV campaign among internally displaced persons in South Sudan, a year after a large cholera outbreak, we enrolled 37 young children (1-5 years old), 67 older children (6-17 years old) and 101 adults (≥18 years old), who received two doses of OCV (Shanchol) spaced approximately 3 weeks apart. Cholera-specific antibody responses were determined at days 0, 21 and 35 post-immunization. High baseline vibriocidal titers (>80) were observed in 21% of the participants, suggesting recent cholera exposure or vaccination. Among those with titers ≤80, 90% young children, 73% older children and 72% adults seroconverted (≥4 fold titer rise) after the 1st OCV dose; with no additional seroconversion after the 2nd dose. Post-vaccination immunological endpoints did not differ across age groups. Our results indicate Shanchol was immunogenic in this vulnerable population and that a single dose alone may be sufficient to achieve similar short-term immunological responses to the currently licensed two-dose regimen. While we found no evidence of differential response by age, further immunologic and epidemiologic studies are needed.

Abstract: Cholera has been for many centuries a permanent feature of life in the slums and poverty-stricken villages in India, particularly in the eastern regions of the country. In this region outbreaks have occurred frequently since the early 1800s1. The first six cholera pandemics originated from this geographical region while the seventh and ongoing pandemic originated in 1961 from Sulawasi in Indonesia. Most recent evidence indicates that within the seventh cholera pandemic two of the three waves of the El Tor biotype of Vibrio cholerae originated from the Gangetic delta off the Bay of Bengal2.

Abstract: In 2013, the Government of Haiti implemented its first oral cholera vaccine (OCV) campaign in Petite Anse, an urban setting, and Cerca Carvajal, a rural commune We conducted and compared responses to two independent cross-sectional knowledge and practices household surveys pre- (N = 297) and post- (N = 302) OCV campaign in Petite Anse No significant differences in knowledge about causes, symptoms, and prevention of cholera were noted Compared with precampaign respondents, fewer postcampaign respondents reported treating (66% versus 27%, P < 0001) and covering (96% versus 89%, P = 002) their drinking water Compared with precampaign, postcampaign survey household observations showed increased availability of soap (162% versus 345%, P = 0001) and handwashing stations (147% versus 301%, P = 001), but no significant changes in handwashing practices were reported Although there was no change in knowledge, significant decreases in water treatment practices necessary for cholera and other diarrheal diseases prevention were noted in the postcampaign survey Future OCV campaigns in Haiti should be used as an opportunity to emphasize the importance of maintaining good water, sanitation, and hygiene practices, and include a comprehensive, integrated approach for cholera control

Abstract: Main problems of system of epidemiologic control for cholera active in Russian Federation, as well as laboratory diagnostics and vaccine prophylaxis of this especially dangerous infection, that had emerged in the contemporary period of the ongoing 7th pandemic of cholera, are discussed. Features of the genome of natural strains of Vibrio cholerae of El Tor biovar, that possess a poten- tial epidemic threat, as well as problems, that have emerged during isolation of these strains from samples of water of surface water bodies during their monitoring, are also examined. The main direction of enhancement of the system of epidemiologic control for cholera consist in develop- ment of a new algorithm of differentiation of administrative territories of Russian Federation by types of epidemic manifestations, as well as optimization of monitoring of environment objects. Integration of modern highly informative technologies into practice, as well as development of new generation diagnostic preparations based on DNA-chips and immunechips is necessary to increase effectiveness of the conducted operative and retrospective diagnostics in the contemporary period. Creation of national cholera vaccine, ensuring simultaneous protection from cholera causative agents of both O1 and O139 serogroups, is also required.

Abstract: Summary Oral cholera vaccination could be deployed in a diverse range of situations from cholera-endemic areas and locations of humanitarian crises, but no clear consensus exists. The supply of licensed, WHO-prequalified cholera vaccines is not sufficient to meet endemic and epidemic needs worldwide and so prioritisation is needed. We have developed a scenario approach to systematically classify situations in which oral cholera vaccination might be useful. Our scenario approach distinguishes between five types of cholera epidemiology based on experiences from around the world and provides evidence that we hope will spur the development of detailed guidelines on how and where oral cholera vaccines could, and should, be most rationally deployed.

Abstract: Introduction Cholera is an extremely virulent diarrhoeal disease that affects both children and adults and can kill within hours if left untreated. Although the disease was largely eliminated from industrialized countries over a century ago by water and sewage treatment, it remains a major cause of morbidity and mortality in many areas of Africa and Asia. Every year, there are an estimated 3 to 5 million cases and 100000 to 120000 deaths due to cholera. (1) Areas where minimum requirements for clean water and sanitation have not been met, such as peri-urban slums and camps for internally displaced people or refugees, are most at risk. (1,2) Although the attack rate of cholera is high, fewer than 25% of those infected become ill. (1) Among people who develop symptoms, 80% have mild or moderate disease, whereas around 20% develop acute watery diarrhoea with severe dehydration. As many as 80% can be treated successfully through prompt administration of oral rehydration salts and, with good or adequate fluid replacement (oral or intravenous), mortality is reduced to about 1%. (3) The causative agent of cholera, Vibrio cholerae, is autochthonous to aquatic environments and cannot be eradicated. However, hydroclimatology-based prediction and prevention is an achievable goal. Access to clean water and adequate sanitation remain the mainstays of preventing both endemic cholera and cholera outbreaks, and health education can promote the adoption of appropriate hygiene practices. 'Cholera vaccination is increasingly being used as a safe and effective additional tool to supplement existing priority cholera control measures under the right conditions. (5,6) In emergencies, vaccines provide immediate, shortGterm protection while interventions to improve access to safe water and sanitation are put into place. Infectious disease can occur in previously vaccinated individuals: primary breakthrough infections are due to vaccine failure, whereas secondary breakthroughs are due to waning protective immunity. In such cases, the disease is usually milder than in the unvaccinated. (7) Two oral cholera vaccines have been prequalified by the World Health organization (WHO): Dukoral[R] and Shanchol". (8, 9) Dukoral* provides 85-90% protection for 6 months in all age groups, whereas Shanchol" ensures 65% protection for at least 5 years in individuals older than 1 year, both following two doses given at an appropriate interval. There is growing evidence that the vaccine also provides herd protection by interrupting disease transmission. A high level of immunization could, therefore, provide even greater protection to populations at risk. (10) In total, more than 1.6 million doses of WHO prequalified oral cholera vaccine have been deployed in mass vaccination campaigns since 1997. (9) In 2012, following the adoption of resolution WHA 64.15 by the 64th World Health Assembly in 2011, (8) a WHO technical working group recommended that global cholera management should be boosted by creating a stockpile of 2 million doses of oral cholera vaccine for use in emergencies. This stockpile would help ensure that countries have rapid access to vaccine for cholera control. The cholera vaccine stockpile was first used in 2014 in South Sudan, which peacefully seceded from Sudan in 2011 after 50 years of conflict. The country has a low level of physical, human and institutional development: (11) in 2010, only 55% of the population had access to improved sources of drinking water and only 20% had access to a toilet facility. (12) As a result, cholera is endemic. In December 2013, renewed fighting led to population displacement and dire overcrowding and inadequate sanitation for internally displaced people at the approach of the rainy season. This prompted the South Sudanese Ministry of Health, together with WHO and other partners, to implement a pre-emptive mass cholera vaccination campaign. When a cholera outbreak was declared in the country 5 months later, it was reported that displaced people living in makeshift camps at United Nations sites where the vaccination campaign took place were largely unaffected. …

Abstract: Background In response to a 2011 cholera outbreak in Papua New Guinea, the Government of the Solomon Islands initiated a cholera prevention program which included cholera disease prevention and treatment messaging, community meetings, and a pre-emptive cholera vaccination campaign targeting 11,000 children aged 1–15 years in selected communities in Choiseul and Western Provinces. Methodology and Principal Findings We conducted a post-vaccination campaign, household-level survey about knowledge, attitudes, and practices regarding diarrhea and cholera in areas targeted and not targeted for cholera vaccination. Respondents in vaccinated areas were more likely to have received cholera education in the previous 6 months (33% v. 9%; p = 0.04), to know signs and symptoms (64% vs. 22%; p = 0.02) and treatment (96% vs. 50%; p = 0.02) of cholera, and to be aware of cholera vaccine (48% vs. 14%; p = 0.02). There were no differences in water, sanitation, and hygiene practices. Conclusions This pre-emptive OCV campaign in a cholera-naive community provided a unique opportunity to assess household-level knowledge, attitudes, and practices regarding diarrhea, cholera, and water, sanitation, and hygiene (WASH). Our findings suggest that education provided during the vaccination campaign may have reinforced earlier mass messaging about cholera and diarrheal disease in vaccinated communities.

Abstract: Background The bivalent whole-cell (BivWC) oral cholera vaccine (Shanchol) is effective in preventing cholera. However, evaluations of immune responses following vaccination with BivWC have been limited. To determine whether BivWC induces significant mucosal immune responses, we measured V. cholerae O1 antigen-specific antibody secreting cell (ASC) responses following vaccination. Methodology/Principal Findings We enrolled 24 Haitian adults in this study, and administered doses of oral BivWC vaccine 14 days apart (day 0 and day 14). We drew blood at baseline, and 7 days following each vaccine dose (day 7 and 21). Peripheral blood mononuclear cells (PBMCs) were isolated, and ASCs were enumerated using an ELISPOT assay. Significant increases in Ogawa (6.9 cells per million PBMCs) and Inaba (9.5 cells per million PBMCs) OSP-specific IgA ASCs were detected 7 days following the first dose (P < 0.001), but not the second dose. The magnitude of V. cholerae-specific ASC responses did not appear to be associated with recent exposure to cholera. ASC responses measured against the whole lipolysaccharide (LPS) antigen and the OSP moiety of LPS were equivalent, suggesting that all or nearly all of the LPS response targets the OSP moiety. Conclusions/Significance Immunization with the BivWC oral cholera vaccine induced ASC responses among a cohort of healthy adults in Haiti after a single dose. The second dose of vaccine resulted in minimal ASC responses over baseline, suggesting that the current dosing schedule may not be optimal for boosting mucosal immune responses to V. cholerae antigens for adults in a cholera-endemic area.

Abstract: SUMMARY A live cholera vaccine was developed from a virulent avian septicemia strain of Pasteurella multocida serotype 1. The virulent parental strain was mutagenized with N-methyl-N'-nitro-N-nitroso guanidine. Mutants were selected that had either smaller colonies at 37 C or temperature sensitivity for growth at 41 C. Four smallcolony mutants and 2 temperature-sensitive mutants were studied. All the mutants were avirulent for turkeys. Sixteen days after turkeys were vaccinated with each mutant, both the vaccinates and unvaccinated controls were challenge-exposed to virulent P. multocida of the homologous serotype and the heterologous serotype 3. Two of the small-colony mutant strains protected against both homologous and heterologous challenge. Suggested for a live cholera vaccine is P. multocida M3G, a small-colony-forming mutant, innocuous for both mice and turkeys and stable against reversion.

Abstract: Vaccines have a long history dating back to the days of Edward Jenner (1749-1823) and Louis Pasteur (1822-1895). Vaccines can be viewed from a public health perspective as well as scientific perspective. Public health experts would focus epidemiological relevance, immunological competency, and technological feasibility. Scientists however will look for a good immune response as well as long-lived immunity, stability considerations, and safety issues such as danger of reversion to virulence. In India, the vaccine coverage is far from satisfactory, national average for full immunization being only 65%. Presently, nine vaccines are being used in the Universal Immunization Program. However, some more have started in pilot, and some are still in the pipeline. Although administrative, logistic and operational challenges have to be faced when introducing a new vaccine into the public health system; these are solvable and should not be a hindrance to the introduction. A real-life example of nonintroduction of a lifesaving vaccine is - the oral cholera vaccine. This vaccine which is manufactured and licensed in India has been the World Health Organization (WHO) prequalified, and it is being used worldwide. Although the disease is a major threat, the disease has its stigma and has led to its low reporting even from cholera endemic areas of the country. Thus, in spite of the WHO recommendations, the vaccine is not being introduced into the national program which would take it to people who need it the most only because of apparent lack of sufficient disease burden data and political commitment.

Abstract: Vibrio cholerae serogroup O1 is the main causative agent of cholera diseases defined by life threatening rice watery diarrhea. Cholera routine vaccination has failed in controlling epidemics in developing countries because of their hard and expensive production. In this study, our aim was to investigate phage displayed mimotopes that could mimic V. cholerae lipopolysaccharide (LPS). Although LPS of Vibrio, as an endotoxin, can stimulate the immune system, thereby making it a suitable candidate for cholera vaccine, its toxicity remains as a main problem. Phage particles displaying 12 amino acid peptides were selected from phage library mimicking the antigenic epitopes of LPS from vibrio. The screening was carried out using single-domain antibody fragment VHH against LPS as target through three rounds of selection. Three clones with highest affinity to VHH were selected. To find out a new and efficient vaccine against cholera, these three phage particles containing high-affinity peptides were administered to mice to investigate the active and passive immunity. Out of 20 particles, three showed the highest affinity toward VHH. ELISA was carried out with immunized mice sera using LPS and three selected phages particles individually. ETEC, Shigella sonnei, and clinical isolates were used as bacterial targets. These three selected phages (individually or in combination) could stimulate mice immune system producing active and passive immunity. The mice immunized with phage particles could protect about 14 LD50 of V. cholerae. In conclusion, these peptides are mimicking LPS and can potentially act as vaccine candidates against V. cholerae. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Abstract: To the Editor: The reported 6-month efficacy of a single dose of oral cholera vaccine in Bangladesh (May 5 issue),1 although seemingly modest, may have profound implications for future use of the vaccine. One-year protection from two doses in India and Bangladesh did not differ significantly from these new results, a finding that suggests that short-term single-dose protection is similar.2,3 In cholera outbreaks, a rapid response is crucial, and protection from the first dose (direct and indirect) will drive the effect of reactive vaccination.4 These findings open the door to rapid provision of a first dose during epidemics, while . . .