Coverage and cost of a large oral cholera vaccination program in a high-risk cholera endemic urban population in Dhaka, Bangladesh

The reactive cholera vaccination campaign in urban Dhaka in 2022: experience, lessons learned and future directions

Introduction

An upsurge of diarrheal cases occurred in Dhaka, Bangladesh, with approximately 30% of the cases being identified as cholera in 2022. To combat this situation, a reactive Oral Cholera Vaccination campaign was organized in five highly cholera-affected areas of Dhaka city. The paper is a descriptive tale of experience gathering, organization and implementation of reactive oral cholera vaccination campaign.

Study design

This is a descriptive report of a reactive oral cholera vaccination campaign.

Methods

Population density maps were generated using GIS technology before launching the campaign. The target population comprised individuals aged over one year, excluding pregnant women, totaling 2,374,976 people residing in above mentioned areas. The campaign utilized Euvichol-Plus, an OCV with adherence to the necessary cold chain requirements. Total 700 teams, each consisting of six members, were deployed across the five zones. The campaign was conducted in two rounds, where first round took place in June-July 2022, followed by second round in August 2022. During the campaign, data on adverse events following immunization (AEFI) was collected. Expert teams from various government and non-government organizations monitored regularly and ensured the campaign's success.

Results

The first round achieved a coverage rate of 99%, whereas in the second round, 86.3% of individuals among the first dose recipients. During the campaigns, a total of 57 AEFIs were reported.

Conclusions

This campaign serves as a model for a multispectral approach in combating cholera epidemics, highlighting the collaborative efforts of policymakers, health authorities, local communities, and health partners.

Oral cholera vaccine coverage evaluation survey: Forcibly Displaced Myanmar Nationals and host community in Cox's Bazar, Bangladesh

Introduction

Cholera remains a significant public health concern in many parts of the world, particularly in areas with poor sanitation and hygiene. Bangladesh and other impoverished nations have been severely affected by cholera outbreaks, especially in areas with a high population density. In order to mitigate the spread of cholera, oral cholera vaccines (OCVs) are recommended as a prophylactic measure. In May 2018, 775,666 of the Forcibly Displaced Myanmar Nationals (FDMN) in the registered and makeshift camps and 103,605 of the residents in the host community received two doses of OCV Shanchol^TM in Cox's Bazar, Bangladesh, because the conditions in the area favored the transmission of cholera and other waterborne diseases. This study aimed to assess the coverage of OCV among the FDMN and the host community in Cox's Bazar.

Methods

In August 2018, we enrolled 4,240 respondents for this study following the "World Health Organization (WHO) Vaccination Coverage Cluster Surveys: Reference Manual (2018)." The coverage survey was conducted with three strata of the population: the host community from the Teknaf Upazila, the registered camp, and the makeshift camp from the Ukhia Upazila. We collected information regarding OCV coverage, demographic characteristics, and knowledge and behaviors of people toward the vaccine. The data were analyzed using descriptive statistics.

Results

According to our study, the overall OCV coverage was 85%, with 68% in the host community, 91% in the registered camp, and 98% in the makeshift camp. The lower coverage in the host community was due to residents unaware of the vaccination campaign, the unavailability of vaccines, and unaware where to go for vaccination.

Discussion

Our findings demonstrate that the OCV campaign in the FDMN camps was successful, reaching over 90% coverage, while coverage in the host community was much lower. In order to make sure that OCV vaccination efforts are reaching the target population and having the desired impact, our study emphasizes the need to inform the target population of when and where to get vaccinated.

Coverage survey and lessons learned from a pre-emptive cholera vaccination campaign in urban and rural communities affected by landslides and floods in Freetown Sierra Leone

BACKGROUND

On 14 August 2017, massive landslides and floods hit Freetown (Sierra Leone). More than 1,000 people lost their lives while approximately 6,000 people were displaced. The areas most affected included parts of the town with challenged access to basic water and sanitation facilities, with communal water sources likely contaminated by the disaster. To avert a possible cholera outbreak following this emergency, the Ministry of Health and Sanitation (MoHS), supported by the World Health Organization (WHO) and international partners, including Médecins Sans Frontières (MSF) and UNICEF, launched a two-dose pre-emptive vaccination campaign using Euvichol™, an oral cholera vaccine (OCV).

METHODS

We conducted a stratified cluster survey to estimate vaccination coverage during the OCV campaign and also monitor adverse events. The study population - subsequently stratified by age group and residence area type (urban/rural) - included all individuals aged 1 year or older, living in one of the 25 communities targeted for vaccination.

RESULTS

In total 3,115 households were visited, 7,189 individuals interviewed; 2,822 (39%) people in rural and 4,367 (61%) in urban areas. The two-dose vaccination coverage was 56% (95% confidence interval (CI): 51.0-61.5), 44% (95%CI: 35.2-53.0) in rural and 57% (95%CI: 51.6-62.8) in urban areas. Vaccination coverage with at least one dose was 82% (95%CI: 77.3-85.5), 61% (95%CI: 52.0-70.2) in rural and 83% (95%CI: 78.5-87.1) in urban areas.

CONCLUSIONS

The Freetown OCV campaign exemplified a timely public health intervention to prevent a cholera outbreak, even if coverage was lower than expected. We hypothesised that vaccination coverage in Freetown was sufficient in providing at least short-term immunity to the population. However, long-term interventions to ensure access to safe water and sanitation are needed.

Impact of COVID ‐19 pandemic on routine vaccination coverage of children and adolescents: A systematic review

Background and Aims

Scientists and healthcare workers have expressed their concerns on the impacts of the COVID‐19 pandemic on vaccination coverage in children and adolescents. Therefore, we aimed to systematically review the studies addressing this issue worldwide.

Methods

We conducted a systematic search of relevant studies using the keywords on databases of PubMed, Web of Science, and Cochrane on May 22, 2021. The identified records were imported into EndNote software and underwent a two‐phase screening process consisting of title/abstract and full‐text screenings against inclusion criteria. The data of the included studies were summarized into a table and the findings were analyzed in a systematic approach.

Results

From 26 eligible studies, 21 studies demonstrated decreased vaccination rates in the children during the COVID‐19 pandemic, while three studies found increased or no significant changes only in influenza vaccination. The two remaining studies from Brazil and Sweden also showed no significant changes in vaccination rates in the children during the pandemic.

Conclusion

Most of the reports worldwide reported a decline or delay in vaccination at the time of the COVID‐19 pandemic. A sustained catch‐up program seems to be necessary, especially in low‐income countries, to avoid any vaccine dose missing. Facilitating the vaccination process is recommended, such as decreasing the waiting time for vaccination at the health center, addressing the fear and concerns related to COVID infection for parents, and enhancing vaccine availability, and promoting access in remote areas. Countries should ensure proper vaccination to prevent future pandemics related to vaccine‐preventable diseases.

Atypical and dual biotypes variant of virulent SA-NAG-Vibrio cholerae: an evidence of emerging/evolving patho-significant strain in municipal domestic water sources

Introduction and purpose

The recent cholera spread, new cases, and fatality continue to arouse concern in public health systems; however, interventions on control is at its peak yet statistics show continuous report. This study characterized atypical and patho-significant environmental Vibrio cholerae retrieved from ground/surface/domestic water in rural-urban-sub-urban locations of Amathole District municipality and Chris Hani District municipality, Eastern Cape Province, South Africa.

Methods

Domestic/surface water was sampled and 759 presumptive V. cholerae isolates were retrieved using standard microbiological methods. Virulence phenotypic test: toxin co-regulated pili (tcp), choleragen red, protease production, lecithinase production, and lipase test were conducted. Serotyping using polyvalent antisera (Bengal and Ogawa/Inaba/Hikojima) and molecular typing: 16SrRNA, OmpW, serogroup (Vc-O1/O139), biotype (tcpAClas/El Tor, HlyAClas/El Tor, rstRClas/El Tor, RS1, rtxA, rtxC), and virulence (ctxA, ctxB, zot, ace, cep, prt, toxR, hlyA) genes were targeted.

Result

Result of 16SrRNA typing confirmed 508 (66.9%) while OmpW detected/confirmed 61 (12.01%) V. cholerae strains. Phenotypic-biotyping scheme showed positive test to polymyxin B (68.9%), Voges proskauer (6.6%), and Bengal serology (11.5%). Whereas Vc-O1/O139 was negative, yet two of the isolates harbored the cholera toxin with a gene-type ctxB and hlyAClas: 2/61, revealing atypical/unusual/dual biotype phenotypic/genotypic features. Other potential atypical genotypes detected include rstR: 7/61, Cep: 15/61, ace: 20/61, hlyAElTor: 53/61, rtxA: 30/61, rtxC: 11/61, and prtV: 15/61 respectively.

Conclusion

Although additional patho-significant/virulent genotypes associated with epidemic/sporadic cholera cases were detected, an advanced, bioinformatics, and post-molecular evaluation is necessary. Such stride possesses potential to adequately minimize future cholera cases associated with dynamic/atypical environmental V. cholerae strains.

A non-inferiority trial comparing two killed, whole cell, oral cholera vaccines (Cholvax vs. Shanchol) in Dhaka, Bangladesh

Bangladesh remains cholera endemic with biannual seasonal peaks causing epidemics. At least 300,000 severe cases and over 4,500 deaths occur each year. The available oral cholera vaccineshave not yet been adopted for cholera control in Bangladesh due to insufficient number of doses available for endemic control. With a public private partnership, icddr,b initiated a collaboration between vaccine manufacturers in Bangladesh and abroad. A locally manufactured Oral Cholera Vaccine (OCV) named Cholvax became available for testing in Bangladesh. We evaluated the safety and immunogenicity of this locally produced Cholvax (Incepta Vaccine Ltd) inexpensive OCV comparatively to Shanchol (Shantha Biotechnics-Sanofi Pasteur) which is licensed in several countries. We conducted a randomized non-inferiority clinical trial of bivalent, killed oral whole-cell cholera vaccine Cholvax vs. Shanchol in the cholera-endemic area of Mirpur, Dhaka, among three different age cohorts (1-5, 6-17 and 18-45 years) between April 2016 and April 2017. Two vaccine doses were given at 14 days apart to 2,052 healthy participants. No vaccine-related serious adverse events were reported. There were no significant differences in the frequency of solicited (7.31% vs. 6.73%) and unsolicited (1.46% vs. 1.07%) adverse events reported between the Cholvax and Shanchol groups. Vibriocidal antibody responses among the overall population for O1 Ogawa (81% vs. 77%) and O1 Inaba (83% vs. 84%) serotypes showed that Cholvax was non-inferior to Shanchol, with the non-inferiority margin of -10%. For O1 Inaba, GMT was 462.60 (Test group), 450.84 (Comparator group) with GMR 1.02(95% CI: 0.92, 1.13). For O1 Ogawa, GMT was 419.64 (Test group), 387.22 (Comparator group) with GMR 1.12 (95% CI: 1.02, 1.23). Cholvax was safe and non-inferior to Shanchol in terms of immunogenicity in the different age groups. These results support public use of Cholvax to contribute for reduction of the cholera burden in Bangladesh. ClinicalTrials.gov number: NCT027425581.

Systematic review of the costs for vaccinators to reach vaccination sites: Incremental costs of reaching hard-to-reach populations

INTRODUCTION

Economic evidence on how much it may cost for vaccinators to reach populations is important to plan vaccination programs. Moreover, knowing the incremental costs to reach populations that have traditionally been undervaccinated, especially those hard-to-reach who are facing supply-side barriers to vaccination, is essential to expanding immunization coverage to these populations.

METHODS

We conducted a systematic review to identify estimates of costs associated with getting vaccinators to all vaccination sites. We searched PubMed and the Immunization Delivery Cost Catalogue (IDCC) in 2019 for the following costs to vaccinators: (1) training costs; (2) labor costs, per diems, and incentives; (3) identification of vaccine beneficiary location; and (4) travel costs. We assessed if any of these costs were specific to populations that are hard-to-reach for vaccination, based on a framework for examining supply-side barriers to vaccination.

RESULTS

We found 19 studies describing average vaccinator training costs at $0.67/person vaccinated or targeted (SD $0.94) and $0.10/dose delivered (SD $0.07). The average cost for vaccinator labor and incentive costs across 29 studies was $2.15/dose (SD $2.08). We identified 13 studies describing intervention costs for a vaccinator to know the location of a beneficiary, with an average cost of $19.69/person (SD $26.65), and six studies describing vaccinator travel costs, with an average cost of $0.07/dose (SD $0.03). Only eight of these studies described hard-to-reach populations for vaccination; two studies examined incremental costs per dose to reach hard-to-reach populations, which were 1.3-2 times higher than the regular costs. The incremental cost to train vaccinators was $0.02/dose, and incremental labor costs for targeting hard-to-reach populations were $0.16-$1.17/dose.

CONCLUSION

Additional comparative costing studies are needed to understand the potential differential costs for vaccinators reaching the vaccination sites that serve hard-to-reach populations. This will help immunization program planners and decision-makers better allocate resources to extend vaccination programs.

Promoting, seeking, and reaching vaccination services: A systematic review of costs to immunization programs, beneficiaries, and caregivers

INTRODUCTION

Understanding the costs to increase vaccination demand among under-vaccinated populations, as well as costs incurred by beneficiaries and caregivers for reaching vaccination sites, is essential to improving vaccination coverage. However, there have not been systematic analyses documenting such costs for beneficiaries and caregivers seeking vaccination.

METHODS

We searched PubMed, Scopus, and the Immunization Delivery Cost Catalogue (IDCC) in 2019 for the costs for beneficiaries and caregivers to 1) seek and know how to access vaccination (i.e., costs to immunization programs for social mobilization and interventions to increase vaccination demand), 2) take time off from work, chores, or school for vaccination (i.e., productivity costs), and 3) travel to vaccination sites. We assessed if these costs were specific to populations that faced other non-cost barriers, based on a framework for defining hard-to-reach and hard-to-vaccinate populations for vaccination.

RESULTS

We found 57 studies describing information, education, and communication (IEC) costs, social mobilization costs, and the costs of interventions to increase vaccination demand, with mean costs per dose at $0.41 (standard deviation (SD) $0.83), $18.86 (SD $50.65) and $28.23 (SD $76.09) in low-, middle-, and high-income countries, respectively. Five studies described productivity losses incurred by beneficiaries and caregivers seeking vaccination ($38.33 per person; SD $14.72; n = 3). We identified six studies on travel costs incurred by beneficiaries and caregivers attending vaccination sites ($11.25 per person; SD $9.54; n = 4). Two studies reported social mobilization costs per dose specific to hard-to-reach populations, which were 2-3.5 times higher than costs for the general population. Eight studies described barriers to vaccination among hard-to-reach populations.

CONCLUSION

Social mobilization/IEC costs are well-characterized, but evidence is limited on costs incurred by beneficiaries and caregivers getting to vaccination sites. Understanding the potential incremental costs for populations facing barriers to reach vaccination sites is essential to improving vaccine program financing and planning.

Cost of vaccine delivery strategies in low- and middle-income countries during the COVID-19 pandemic

Background

The COVID-19 pandemic has disrupted immunization services critical to the prevention of vaccine-preventable diseases in many low- and middle- income countries around the world. These services will need to be modified in order to minimize COVID-19 transmission and ensure the safety of health workers and the community. Additional budget will be required to implement these modifications that ensure safe delivery.

Methods

Using a simple modeling analysis, we estimated the additional resource requirements associated with modifications to supplementary immunization activities (campaigns) and routine immunization services via fixed sites and outreach in 2020 US dollars. We considered the following four categories of costs: (1) personal protective equipment (PPE) & infection prevention and control (IPC) measures for immunization sessions; (2) physical distancing and screening during immunization sessions; (3) delivery strategy changes, such as changes in session sizes and frequency; and (4) other operational cost increases, including additional social mobilization, training, and hazard pay to compensate health workers.

Results

We found that implementing a range of measures to protect health workers and communities from COVID-19 transmission could result in a per-facility start-up cost of $466–799 for routine fixed-site delivery and $12–220 for routine outreach delivery, and $12–108 per immunization campaign site. A recurrent monthly cost of $137–1,024 for fixed-site delivery and $152–848 for outreach delivery per facility could be incurred, and a $0.32–0.85 increase in the cost per dose during campaigns.

Conclusions

By illustrating potential cost implications of providing immunization services through a range of strategies in a safe manner, these estimates can provide a benchmark for program managers and policy makers on the additional budget required. These findings can help country practitioners and global development partners planning the continuation of immunization services in the context of COVID-19.

Effectiveness of a killed whole-cell oral cholera vaccine in Bangladesh: further follow-up of a cluster-randomised trial

BACKGROUND

Killed whole-cell oral cholera vaccines (OCVs) are widely used for prevention of cholera in developing countries. However, few studies have evaluated the protection conferred by internationally recommended OCVs for durations beyond 2 years of follow-up.

METHODS

In this study, we followed up the participants of a cluster-randomised controlled trial for 2 years after the end of the original trial. Originally, we had randomised 90 geographical clusters in Dhaka slums in Bangladesh in equal numbers (1:1:1) to a two-dose regimen of OCV alone (targeted to people aged 1 year or older), a two-dose regimen of OCV plus a water-sanitation-hygiene (WASH) intervention, or no intervention. There was no masking of group assignment. The WASH intervention conferred little additional protection to OCV and was discontinued at 2 years of follow-up. Surveillance for severe cholera was continued for 4 years. Because of the short duration and effect of the WASH intervention, we combined the two OCV intervention groups. The primary outcomes were OCV overall protection (protection of all members of the intervention clusters) and total protection (protection of individuals who got vaccinated in the intervention clusters) against severe cholera, which we assessed by multivariable survival models appropriate for cluster-randomised trials. This trial is registered on ClinicalTrials.gov, NCT01339845.

FINDINGS

The study was done between April 17, 2011, and Nov 1, 2015. 268 896 participants were present at the time of the first dose, with 188 206 in the intervention group and 80 690 in the control group. OCV coverage of the two groups receiving OCV was 66% (123 659 of 187 214 participants). During 4 years of follow-up, 441 first episodes of severe cholera were detected (243 episodes in the vaccinated groups and as 198 episodes in the unvaccinated group). Overall OCV protection was 36% (95% CI 19 to 49%) and total OCV protection was 46% (95% CI 32 to 58). Cumulative total vaccine protection was notably lower for people vaccinated before the age of 5 years (24%; -30 to 56) than for people vaccinated at age 5 years or older (49%; 35 to 60), although the differences in protection for the two age groups were not significant (p=0·3308). Total vaccine protection dropped notably (p=0·0115) after 3 years in children vaccinated at 1-4 years of age.

INTERPRETATION

These findings provide further evidence of long-term effectiveness of killed whole-cell OCV, and therefore further support for the use of killed whole-cell OCVs to control endemic cholera, but indicate that protection is shorter-lived in children vaccinated before the age of 5 years than in people vaccinated at the age of 5 years or older.

FUNDING

Bill & Melinda Gates Foundation.

TRANSLATION

For the Bengali translation of the abstract see Supplementary Materials section.

Childhood vaccinations: Hidden impact of COVID-19 on children in Singapore

Although the direct health impact of Coronavirus disease (COVID-19) pandemic on child health is low, there are indirect impacts across many aspects. We compare childhood vaccine uptake in three types of healthcare facilities in Singapore - public primary care clinics, a hospital paediatric unit, and private paediatrician clinics - from January to April 2020, to baseline, and calculate the impact on herd immunity for measles. We find a 25.6% to 73.6% drop in Measles-Mumps-Rubella (MMR) uptake rates, 0.4 - 10.3% drop for Diphtheria-Tetanus-Pertussis-inactivated Polio-Haemophilus influenza (5-in-1), and 8.0-67.8% drop for Pneumococcal conjugate vaccine (PCV) across all 3 sites. Consequent herd immunity reduces to 74-84% among 12-month- to 2-year-olds, well below the 95% coverage that is protective for measles. This puts the whole community at risk for a measles epidemic. Public health efforts are urgently needed to maintain efficacious coverage for routine childhood vaccines during the COVID-19 pandemic.

Costing oral cholera vaccine delivery using a generic oral cholera vaccine delivery planning and costing tool (CholTool)

Cholera is both an endemic and epidemic disease in many low and middle-income countries (LMICs). Strategies for cholera control include improving water, sanitation, and hygiene; providing early and effective treatment; and deploying oral cholera vaccine (OCV). This last strategy is relatively new, and countries considering its introduction are interested in knowing the potential cost not only of the vaccine, but also the cost of introduction. This paper describes the costing of OCV introduction in LMICs using a publicly available Excel-based tool known as the CholTool. It includes estimates of delivery cost categories which cover not only the service delivery costs (e.g. vaccine procurement, handling, storage, and transport; vaccination administration, monitoring supervision, and field support), but also the programmatic costs associated with introducing a new vaccine (i.e. microplanning, communication and training materials development, sensitization/social mobilization, and personnel training) to ensure that a comprehensive estimate is provided with health payer perspective. CholTool takes the user through a structured sequence of interlinked modules containing input parameter cells (assumptions), decision cells (variable selections), and formulas (calculations) to produce customized cost estimates based on standardized methods. The tool provides both financial and economic cost estimates, to ensure that both costs are available for consideration. Four examples of applications of CholTool are presented in three countries- one in Ethiopia, two in Malawi and one in Nepal. The estimates of economic delivery cost per dose (including service delivery and programmatic costs) were (in USD 2016): $2.89 in Ethiopia, $3.04 in Malawi1, $3.35 in Malawi2 and $3.06 in Nepal. A cost projection conducted before the campaign using the tool and a retrospective costing using the tool in Nepal resulted in no significant difference between economic delivery costs per dose.

The reactive vaccination campaign against cholera emergency in camps for internally displaced persons, Borno, Nigeria, 2017: a two-stage cluster survey

INTRODUCTION

In 2017, amidst insecurity and displacements posed by Boko Haram armed insurgency, cholera outbreak started in the Muna Garage camp for Internally Displaced Persons (IDPs) in Borno State, Nigeria. In response, the Borno Ministry of Health and partners determined to provide oral cholera vaccine (OCV) to about 1 million people in IDP camps and surrounding communities in six Local Government Areas (LGAs) including Maiduguri, Jere, Konduga, Mafa, Dikwa, and Monguno. As part of Monitoring and Evaluation, we described the coverage achieved, adverse events following immunisation (AEFI), non-vaccination reasons, vaccination decisions as well as campaign information sources.

METHODS

We conducted two-stage probability cluster surveys with clusters selected without replacement according to probability-proportionate-to-population-size in the six LGAs targeted by the campaign. Individuals aged ≥1 years were the eligible study population. Data sources were household interviews with vaccine card verification and memory recall, if no card, as well as multiple choice questions with an open-ended option.

RESULTS

Overall, 12 931 respondents participated in the survey. Overall, 90% (95% CI: 88 to 92) of the target population received at least one dose of OCV, range 87% (95% CI: 75 to 94) in Maiduguri to 94% (95% CI: 88 to 97) in Monguno. The weighted two-dose coverage was 73% (95% CI: 68 to 77) with a low of 68% (95% CI: 46 to 86) in Maiduguri to a high of 87% (95% CI: 74 to 95) in Dikwa. The coverage was lower during first round (76%, 95% CI: 71 to 80) than second round (87%, 95% CI: 84 to 89) and ranged from 72% (95% CI: 42 to 89) and 82% (95% CI: 82 to 91) in Maiduguri to 87% (95% CI: 75 to 95) and 94% (95% CI: 88 to 97) in Dikwa for the respective first and second rounds. Also, coverage was higher among females of age 5 to 14 and ≥15 years than males of same age groups. There were mild AEFI with the most common symptoms being fever, headache and diarrhoea occurring up to 48 hours after ingesting the vaccine. The most common actions taken after AEFI symptoms included 'did nothing' and 'self-medicated at home'. The top reason for taking vaccine was to protect from cholera while top reason for non-vaccination was travel/work. The main source of campaign information was a neighbour. An overwhelming majority (96%, 95% CI: 95% to 98%) felt the campaign team treated them with respect. While 43% (95% CI: 36% to 50%) asked no questions, 37% (95% CI: 31% to 44%) felt the team addressed all their concerns.

CONCLUSION

The campaign achieved high coverage using door-to-door and fixed sites strategies amidst insecurity posed by Boko Haram. Additional studies are needed to improve how to reduce non-vaccination, especially for the first round. While OCV provides protection for a few years, additional actions will be needed to make investments in water, sanitation and hygiene infrastructure.

High cholera vaccination coverage following emergency campaign in Haiti: Results from a cluster survey in three rural Communes in the South Department, 2017

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.

After Hurricane Matthew hit Southern Haiti on October 4, 2016, there was an outbreak of Cholera. The Government launched a campaign to vaccinate residents using an oral vaccine, which has been proven to protect people against the disease. MSF supported the campaign in three rural areas, offering the vaccine in local clinics and going from door to door. We didn’t know how many people were living there at the time so we couldn’t say for sure if we had vaccinated enough people. To find out how many people were vaccinated we did a survey, choosing households at random and asking them if and where they received the vaccine. This showed that on average around 90% of people were vaccinated, which is a very high proportion. We can take encouragement from this that mass vaccination campaigns like this can work well, even in rural settings. Our survey showed that about half of people got their vaccine from a clinic and the other half from door-to-door vaccinators, so it’s probably important to use both approaches. Most people heard about the campaign through members of the local community called ‘criers’. This shows how important it is to engage with the local community during a vaccination campaign.

The projected impact of geographic targeting of oral cholera vaccination in sub-Saharan Africa: A modeling study

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.

Systematic review of the costs and effectiveness of interventions to increase infant vaccination coverage in low- and middle-income countries

Background

In recent years, several large studies have assessed the costs of national infant immunization programs, and the results of these studies are used to support planning and budgeting in low- and middle-income countries. However, few studies have addressed the costs and cost-effectiveness of interventions to improve immunization coverage, despite this being a major focus of policy attention. Without this information, countries and international stakeholders have little objective evidence on the efficiency of competing interventions for improving coverage.

Methods

We conducted a systematic literature review on the costs and cost-effectiveness of interventions to improve immunization coverage in low- and middle-income countries, including both published and unpublished reports. We evaluated the quality of included studies and extracted data on costs and incremental coverage. Where possible, we calculated incremental cost-effectiveness ratios (ICERs) to describe the efficiency of each intervention in increasing coverage.

Results

A total of 14 out of 41 full text articles reviewed met criteria for inclusion in the final review. Interventions for increasing immunization coverage included demand generation, modified delivery approaches, cash transfer programs, health systems strengthening, and novel technology usage. We observed substantial heterogeneity in costing methods and incompleteness of cost and coverage reporting. Most studies reported increases in coverage following the interventions, with coverage increasing by an average of 23 percentage points post-intervention across studies. ICERs ranged from $0.66 to $161.95 per child vaccinated in 2017 USD. We did not conduct a meta-analysis given the small number of estimates and variety of interventions included.

Conclusions

There is little quantitative evidence on the costs and cost-effectiveness of interventions for improving immunization coverage, despite this being a major objective for national immunization programs. Efforts to improve the level of costing evidence—such as by integrating cost analysis within implementation studies and trials of immunization scale up—could allow programs to better allocate resources for coverage improvement. Greater adoption of standardized cost reporting methods would also enable the synthesis and use of cost data.

Electronic supplementary material

The online version of this article (10.1186/s12913-019-4468-4) contains supplementary material, which is available to authorized users.

Organization and implementation of an oral cholera vaccination campaign in an endemic urban setting in Dhaka, Bangladesh

Bangladesh has historically been cholera endemic, with seasonal cholera outbreaks occurring each year. In collaboration with the government of Bangladesh, the Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) initiated operational research to test strategies to reach the high-risk urban population with an affordable oral cholera vaccine (OCV) “ShancholTM” and examine its effectiveness in reducing diarrhea due to cholera. Here we report a sub-analysis focusing on the organization, implementation and effectiveness of different oral cholera vaccine delivery strategies in the endemic urban setting in Bangladesh. We described how the vaccination program was planned, prepared and implemented using different strategies to deliver oral cholera vaccine to a high-risk urban population in Dhaka, Bangladesh based on administrative data and observations made during the program. The objective of this study is to evaluate the organization, implementation and effectiveness of different oral cholera vaccine delivery strategies in the endemic urban setting in Bangladesh. OCV administration by trained local volunteers through outreach sites and mop-up activities yielded high coverage of 82% and 72% of 172,754 targeted individuals for the first and second dose respectively, using national Expanded Program on Immunization (EPI) campaign mechanisms without disrupting routine immunization activities. The cost of delivery was low. Safety and cold chain requirements were adequately managed. The adopted strategies were technically and programmatically feasible. Current evidence on implementation strategies in different settings together with available OCV stockpiles should encourage at-risk countries to use OCV along with other preventive and control measures.

Delayed second dose of oral cholera vaccine administered before high-risk period for cholera transmission: Cholera control strategy in Lusaka, 2016

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.

Post-vaccination campaign coverage evaluation of oral cholera vaccine, oral polio vaccine and measles-rubella vaccine among Forcibly Displaced Myanmar Nationals in Bangladesh

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.

Oral cholera vaccine delivery strategy in India: Routine or campaign?-A scoping review

Oral Cholera Vaccine (OCV) has been recognized as an adjunct tool for prevention and control of cholera. However, policy directions are currently unavailable in India to guide the vaccine delivery. We conducted a scoping review to inform the policy about the scopes and challenges of different strategic choices of OCV delivery in India in light of current evidences, highlighting the scope of new research.

METHODS

Adopting the Arksey and O'Malley Framework for review, we searched for literatures on "efficacy", "effectiveness", and "cost" of oral cholera vaccine delivery through different strategies in Pubmed and Scopus.

RESULTS

We found that the protective efficacy of OCV depends on its coverage. Evidence on effectiveness of OCV are available for both reactive and pre-vaccination campaigns. Reactive high-risk vaccination is more effective than reactive ring and mass vaccination. Pre-vaccination campaigns are more effective than reactive vaccination when vaccine availability is adequate. Pre-vaccination through school campaigns in 1-14 years age group have been cost effective in India. Vaccination campaigns in under-5 children are also cost effective in spite of low efficacy due to the scope of averting a higher number of cases. However, no evidence is available regarding efficacy and effectiveness of OCV in children <1 year as well as the effectiveness of delivering OCV through routine immunization.

CONCLUSION

Little evidence exist to depict mass-campaign as more economic and effective than routine expanded programme on immunization (EPI) session for delivery of OCV. Considering operational feasibility, it needs to be explored whether OCV delivery strategy is compatible with India's current EPI, if it can be introduced in routine immunization at measles containing vaccine age-schedule, optionally preceded by a campaign in targeted hot-spots in the 1-14 year age-group. Safety and efficacy data of OCV during infancy as well as hot-spot surveillance are pre-requisites for formulation of such EPI policy.

Evaluating the costs of cholera illness and cost-effectiveness of a single dose oral vaccination campaign in Lusaka, Zambia

INTRODUCTION

In 2016, for the very first time, the Ministry of Health in Zambia implemented a reactive outbreak response to control the spread of cholera and vaccinated at-risk populations with a single dose of Shancol-an oral cholera vaccine (OCV). This study aimed to assess the costs of cholera illness and determine the cost-effectiveness of the 2016 vaccination campaign.

METHODOLOGY

From April to June 2017, we conducted a retrospective cost and cost-effectiveness analysis in three peri-urban areas of Lusaka. To estimate costs of illness from a household perspective, a systematic random sample of 189 in-patients confirmed with V. cholera were identified from Cholera Treatment Centre registers and interviewed for out-of-pocket costs. Vaccine delivery and health systems costs were extracted from financial records at the District Health Office and health facilities. The cost of cholera treatment was derived by multiplying the subsidized cost of drugs by the quantity administered to patients during hospitalisation. The cost-effectiveness analysis measured incremental cost-effectiveness ratio-cost per case averted, cost per life saved and cost per DALY averted-for a single dose OCV.

RESULTS

The mean cost per administered vaccine was US$1.72. Treatment costs per hospitalized episode were US$14.49-US$18.03 for patients ≤15 years old and US$17.66-US$35.16 for older patients. Whereas households incurred costs on non-medical items such as communication, beverages, food and transport during illness, a large proportion of medical costs were borne by the health system. Assuming vaccine effectiveness of 88.9% and 63%, a life expectancy of 62 years and Gross Domestic Product (GDP) per capita of US$1,500, the costs per case averted were estimated US$369-US$532. Costs per life year saved ranged from US$18,515-US$27,976. The total cost per DALY averted was estimated between US$698-US$1,006 for patients ≤15 years old and US$666-US$1,000 for older patients.

CONCLUSION

Our study determined that reactive vaccination campaign with a single dose of Shancol for cholera control in densely populated areas of Lusaka was cost-effective.

Oral cholera vaccination strategy: Self-administration of the second dose in urban Dhaka, Bangladesh

Cholera remains a major public health problem in many developing countries including Bangladesh. The oral cholera vaccine (OCV) is now considered a key component of the public health response to cholera. Although maintaining cold chain and organizing human resource are the major challenges of vaccine delivery to the community. Here we applied an innovative approach to second dose OCV delivery to minimize financial and logistic burdens. The purpose of this study was to assess the feasibility and compliance of second dose self-administration when the second dose was provided in a plastic bag to first dose vaccine recipients as OCV is stable for up to 42 days at ambient temperatures. We aimed to deploy vaccines (N = 112,000) left over from other studies to 56,000 people aged ≥ one year living in Mirpur, Dhaka to see the feasibility of self-administration strategy. During vaccination, the first OCV dose (OCV1) was given from fixed sites and the second dose (OCV2) was provided in a plastic zip-lock bag for the participant to take the vaccine two weeks later at home. Participants were instructed to keep the vaccine away from light and in a dry cool place. Empty vials were collected following the end date of the scheduled second vaccination. Of the targeted population, 41,694 (74%) received the first OCV dose whereas an estimated 38,852 (93% of those receiving the first dose) received the second dose which represents a 7% drop out rate from OCV1 to OCV2. However the average two dose coverage was 69%. A survey of a subsample 2990 (from 8551) randomly selected households revealed that almost all respondents (98.75%) appreciated this new self-administration strategy and considered the strategy to be more practical and convenient than the usual method. This simplified, self-administered delivery strategy provides an ideal alternative for second-dose OCV delivery in hard-to-reach populations and resource-poor settings.

Feasibility, coverage and cost of oral cholera vaccination conducted by icddr,b using the existing national immunization service delivery mechanism in rural setting Keraniganj, Bangladesh

Background: Cholera is a considerable health burden in developing country settings including Bangladesh. The oral cholera vaccine (OCV) is a preventative tool to control the disease. The objective of this study was to describe whether the International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), could provide the OCV to rural communities using existing government infrastructure.

Methods: The study was conducted in rural sub-district Keraniganj, 20 km from the capital city Dhaka. All listed participants one year and above in age (excluding pregnant women) were offered two doses of OCV at a 14 day interval. Existing government facilities were used to deliver and also maintain the cold chain required for the vaccine. All events related to vaccination were recorded at the 17 vaccination sites to evaluate the coverage and feasibility of OCV program.

Results: A total of 29,029 individuals received the 1st dose (90% of target) and 26,611 individuals received the 2nd dose (83% of target and 92% of 1st dose individuals) of OCV. The highest vaccination coverage was in younger children (1–9 years) and the lowest was amongst 18–29-year age group. Somewhat better coverage was seen amongst the female participants than males (92% vs. 88% for the 1st dose and 93% vs. 90% for the 2nd dose). The cost of vaccine cost was calculated as US$1.00 per dose plus freight, insurance, and transportation and the total vaccine delivery cost was US$70,957.

Conclusion: This was a project undertaken using existing public health program resources to collect empirical evidence on the use of a mass OCV campaign in the rural setting. Mass vaccination with the OCV is feasible in the rural setting using existing governmental vaccine delivery systems in Bangladesh.

The impact and cost-effectiveness of controlling cholera through the use of oral cholera vaccines in urban Bangladesh: A disease modeling and economic analysis

BACKGROUND

Cholera remains an important public health problem in major cities in Bangladesh, especially in slum areas. In response to growing interest among local policymakers to control this disease, this study estimated the impact and cost-effectiveness of preventive cholera vaccination over a ten-year period in a high-risk slum population in Dhaka to inform decisions about the use of oral cholera vaccines as a key tool in reducing cholera risk in such populations.

METHODOLOGY/PRINCIPAL FINDINGS

Assuming use of a two-dose killed whole-cell oral cholera vaccine to be produced locally, the number of cholera cases and deaths averted was estimated for three target group options (1-4 year olds, 1-14 year olds, and all persons 1+), using cholera incidence data from Dhaka, estimates of vaccination coverage rates from the literature, and a dynamic model of cholera transmission based on data from Matlab, which incorporates herd effects. Local estimates of vaccination costs minus savings in treatment costs, were used to obtain incremental cost-effectiveness ratios for one- and ten-dose vial sizes. Vaccinating 1-14 year olds every three years, combined with annual routine vaccination of children, would be the most cost-effective strategy, reducing incidence in this population by 45% (assuming 10% annual migration), and costing was $823 (2015 USD) for single dose vials and $591 (2015 USD) for ten-dose vials per disability-adjusted life year (DALY) averted. Vaccinating all ages one year and above would reduce incidence by >90%, but would be 50% less cost-effective ($894-1,234/DALY averted). Limiting vaccination to 1-4 year olds would be the least cost-effective strategy (preventing only 7% of cases and costing $1,276-$1,731/DALY averted), due to the limited herd effects of vaccinating this small population and the lower vaccine efficacy in this age group.

CONCLUSIONS/SIGNIFICANCE

Providing cholera vaccine to slum populations in Dhaka through periodic vaccination campaigns would significantly reduce cholera incidence and inequities, and be especially cost-effective if all 1-14 year olds are targeted.

Systematic review of the incremental costs of interventions that increase immunization coverage

Achieving and maintaining high vaccination coverage requires investments, but the costs and effectiveness of interventions to increase coverage remain poorly characterized. We conducted a systematic review of the literature to identify peer-reviewed studies published in English that reported interventions aimed at increasing immunization coverage and the associated costs and effectiveness of the interventions. We found limited information in the literature, with many studies reporting effectiveness estimates, but not providing cost information. Using the available data, we developed a cost function to support future programmatic decisions about investments in interventions to increase immunization coverage for relatively low and high-income countries. The cost function estimates the non-vaccine cost per dose of interventions to increase absolute immunization coverage by one percent, through either campaigns or routine immunization. The cost per dose per percent increase in absolute coverage increased with higher baseline coverage, demonstrating increasing incremental costs required to reach higher coverage levels. Future studies should evaluate the performance of the cost function and add to the database of available evidence to better characterize heterogeneity in costs and generalizability of the cost function.

The health economics of cholera: A systematic review

BACKGROUND

Vibrio cholera is a major contributor of diarrheal illness that causes significant morbidity and mortality globally. While there is literature on the health economics of diarrheal illnesses more generally, few studies have quantified the cost-of-illness and cost-effectiveness of cholera-specific prevention and control interventions. The present systematic review provides a comprehensive overview of the literature specific to cholera as it pertains to key health economic measures.

METHODS

A systematic review was performed with no date restrictions up through February 2017 in PubMed, Econlit, Embase, Web of Science, and Cochrane Review to identify relevant health economics of cholera literature. After removing duplicates, a total of 1993 studies were screened and coded independently by two reviewers, resulting in 22 relevant studies. Data on population, methods, and results (cost-of-illness and cost-effectiveness of vaccination) were compared by country/region. All costs were adjusted to 2017 USD for comparability.

RESULTS

Costs per cholera case were found to be rather low: <$100 per case in most settings, even when costs incurred by patients/families and lost productivity are considered. When wider socioeconomic costs are included, estimated costs are >$1000/case. There is adequate evidence to support the economic value of vaccination for the prevention and control of cholera when vaccination is targeted at high-incidence populations and/or areas with high case fatality rates due to cholera. When herd immunity is considered, vaccination also becomes a cost-effective option for the general population and is comparable in cost-effectiveness to other routine immunizations.

CONCLUSIONS

Cholera vaccination is a viable short-to-medium term option, especially as the upfront costs of building water, sanitation, and hygiene (WASH) infrastructure are considerably higher for countries that face a significant burden of cholera. While WASH may be the more cost-effective solution in the long-term when implemented properly, cholera vaccination can still be a feasible, cost-effective strategy.

Feasibility and costs of a targeted cholera vaccination campaign in Ethiopia

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.

Socioeconomic drivers of vaccine uptake: An analysis of the data of a geographically defined cluster randomized cholera vaccine trial in Bangladesh

BACKGROUND

Evaluations of oral cholera vaccines (OCVs) have demonstrated their effectiveness in diverse settings. However, low vaccine uptake in some settings reduces the opportunity for prevention. This paper identifies the socioeconomic factors associated with vaccine uptake in a mass vaccination program.

METHODS

This was a three-arm (vaccine, vaccine plus behavioral change, and non-intervention) cluster randomized trial conducted in Dhaka, Bangladesh. Socio-demographic and vaccination data were collected from 268,896 participants. A geographical information system (GIS) was used to design and implement the vaccination program. A logistic regression model was used to assess the association between vaccine uptake and socioeconomic characteristics.

RESULTS

The GIS supported the implementation of the vaccination program by identifying ideal locations of vaccination centres for equitable population access, defining catchment areas of daily activities, and providing daily coverage maps during the campaign. Among 188,206 individuals in the intervention arms, 123,686 (66%) received two complete doses, and 64,520 (34%) received one or no doses of the OCV. The vaccine uptake rate was higher in females than males (aOR: 1.80; 95% CI = 1.75-1.84) and in younger (<15 years) than older participants (aOR: 2.19; 95% CI = 2.13-3.26). Individuals living in their own house or having a higher monthly family expenditure were more likely to receive the OCV (aOR: 1.60; 95% CI = 1.50-1.70 and aOR: 1.14; 95% CI = 1.10-1.18 respectively). Individuals using treated water for drinking or using own tap as the source of water were more likely to receive the OCV (aOR: 1.23; 95% CI = 1.17-1.29 and aOR: 1.14; 95% CI = 1.02-1.25 respectively) than their counterpart. Vaccine uptake was also significantly higher in participants residing farther away from health facilities (aOR: 95% 1.80; CI = 1.36-2.37).

CONCLUSION

The GIS was useful in designing field activities, facilitating vaccine delivery and identifying socioeconomic drivers of vaccine uptake in the urban area of Bangladesh. Addressing these socioeconomic drivers may help improve OCV uptake, thereby effectiveness of the OCV in a community.

Highly targeted cholera vaccination campaigns in urban setting are feasible: The experience in Kalemie, Democratic Republic of Congo

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 Médecins Sans Frontières 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.

The oral cholera vaccine, Shanchol, has already been shown as an effective tool in controlling a cholera outbreak. The limited amount of doses, concurrently with the logistic constraints associated with a targeted vaccination campaign are serious difficulties to tackle in order to organize a vaccination campaign in an urban setting. Although the World Health Organization recommends its use for cholera control in endemic countries, the fact remains that the use of the oral cholera vaccine in endemic setting has scarcely been described, especially in an urban setting, until now. Médecins Sans Frontières and the Ministry of Health from Democratic Republic of Congo organized a vaccination campaign of a limited part of the urbanized and highly endemic city of Kalemie, in the Tanganyika Province using a door to door strategy. The vaccine coverage in the targeted zones was high and demonstrated the feasibility of cholera vaccination campaign in this setting but also the need for creative strategies in order to reach population remaining hard to vaccine.

Efficacy of a single-dose regimen of inactivated whole-cell oral cholera vaccine: results from 2 years of follow-up of a randomised trial

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.

Oral Cholera Vaccine Coverage during an Outbreak and Humanitarian Crisis, Iraq, 2015

During November–December 2015, as part of the 2015 cholera outbreak response in Iraq, the Iraqi Ministry of Health targeted ≈255,000 displaced persons >1 year of age with 2 doses of oral cholera vaccine (OCV). All persons who received vaccines were living in selected refugee camps, internally displaced persons camps, and collective centers. We conducted a multistage cluster survey to obtain OCV coverage estimates in 10 governorates that were targeted during the campaign. In total, 1,226 household and 5,007 individual interviews were conducted. Overall, 2-dose OCV coverage in the targeted camps was 87% (95% CI 85%–89%). Two-dose OCV coverage in the 3 northern governorates (91%; 95% CI 87%–94%) was higher than that in the 7 southern and central governorates (80%; 95% CI 77%–82%). The experience in Iraq demonstrates that OCV campaigns can be successfully implemented as part of a comprehensive response to cholera outbreaks among high-risk populations in conflict settings.

Delivery cost analysis of a reactive mass cholera vaccination campaign: a case study of Shanchol™ vaccine use in Lake Chilwa, Malawi

BACKGROUND

Cholera is a diarrheal disease that produces rapid dehydration. The infection is a significant cause of mortality and morbidity. Oral cholera vaccine (OCV) has been propagated for the prevention of cholera. Evidence on OCV delivery cost is insufficient in the African context. This study aims to analyze Shanchol vaccine delivery costs, focusing on the vaccination campaign in response of a cholera outbreak in Lake Chilwa, Malawi.

METHODS

The vaccination campaign was implemented in two rounds in February and March 2016. Structured questionnaires were used to collect costs incurred for each vaccination related activity, including vaccine procurement and shipment, training, microplanning, sensitization, social mobilization and vaccination rounds. Costs collected, including financial and economic costs were analyzed using Choltool, a standardized cholera cost calculator.

RESULTS

In total, 67,240 persons received two complete doses of the vaccine. Vaccine coverage was higher in the first round than in the second. The two-dose coverage measured with the immunization card was estimated at 58%. The total financial cost incurred in implementing the campaign was US$480275 while the economic cost was US$588637. The total financial and economic costs per fully vaccinated person were US$7.14 and US$8.75, respectively, with delivery costs amounting to US$1.94 and US$3.55, respectively. Vaccine procurement and shipment accounted respectively for 73% and 59% of total financial and economic costs of the total vaccination campaign costs while the incurred personnel cost accounted for 13% and 29% of total financial and economic costs. Cost for delivering a single dose of Shanchol was estimated at US$0.97.

CONCLUSION

This study provides new evidence on economic and financial costs of a reactive campaign implemented by international partners in collaboration with MoH. It shows that involvement of international partners' personnel may represent a substantial share of campaign's costs, affecting unit and vaccine delivery costs.

Cost Evaluation of a Government-Conducted Oral Cholera Vaccination Campaign-Haiti, 2013

The devastating 2010 cholera epidemic in Haiti prompted the government to introduce oral cholera vaccine (OCV) in two high-risk areas of Haiti. We evaluated the direct costs associated with the government's first vaccine campaign implemented in August-September 2013. We analyzed data for major cost categories and assessed the efficiency of available campaign resources to vaccinate the target population. For a target population of 107,906 persons, campaign costs totaled $624,000 and 215,295 OCV doses were dispensed. The total vaccine and operational cost was $2.90 per dose; vaccine alone cost $1.85 per dose, vaccine delivery and administration $0.70 per dose, and vaccine storage and transport $0.35 per dose. Resources were greater than needed-our analyses suggested that approximately 2.5-6 times as many persons could have been vaccinated during this campaign without increasing the resources allocated for vaccine delivery and administration. These results can inform future OCV campaigns in Haiti.

Implementation research: reactive mass vaccination with single-dose oral cholera vaccine, Zambia

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 Médecins Sans Frontières 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.

Climate-driven endemic cholera is modulated by human mobility in a megacity

Although a differential sensitivity of cholera dynamics to climate variability has been reported in the spatially heterogeneous megacity of Dhaka, Bangladesh, the specific patterns of spread of the resulting risk within the city remain unclear. We build on an established probabilistic spatial model to investigate the importance and role of human mobility in modulating spatial cholera transmission. Mobility fluxes were inferred using a straightforward and generalizable methodology that relies on mapping population density based on a high resolution urban footprint product, and a parameter-free human mobility model. In accordance with previous findings, we highlight the higher sensitivity to the El Niño Southern Oscillation (ENSO) in the highly populated urban center than in the more rural periphery. More significantly, our results show that cholera risk is largely transmitted from the climate-sensitive core to the periphery of the city, with implications for the planning of control efforts. In addition, including human mobility improves the outbreak prediction performance of the model with an 11 month lead. The interplay between climatic and human mobility factors in cholera transmission is discussed from the perspective of the rapid growth of megacities across the developing world.

Socioeconomic risk factors for cholera in different transmission settings: An analysis of the data of a cluster randomized trial in Bangladesh

BACKGROUND

Cholera remains a threat globally, and socioeconomic factors play an important role in transmission of the disease. We assessed socioeconomic risk factors for cholera in vaccinated and non-vaccinated communities to understand whether the socioeconomic risk factors differ by transmission patterns for cholera.

METHODS

We used data from a cluster randomized control trial conducted in Dhaka, Bangladesh. There were 90 geographic clusters; 30 in each of the three arms of the study: vaccine (VAC), vaccine plus behavioural change (VBC), and non-intervention. The data were analysed for the three populations: (1) vaccinees in the vaccinated communities (VAC and VBC arms), (2) non-vaccinated individuals in the vaccinated communities and (3) all individuals in the non-vaccinated communities (non-intervention arm). A generalized estimating equation with logit link function was used to evaluate the risk factors for cholera among these different populations adjusting for household level correlation in the data.

RESULTS

A total of 528 cholera and 226 cholera with severe dehydration (CSD) in 268,896 persons were observed during the two-year follow-up. For population 1, the cholera risk was not associated with any socioeconomic factors; however CSD was less likely to occur among individuals living in a household having ≤4 members (aOR=0.55, 95% CI=0.32-0.96). Among population 2, younger participants and individuals reporting diarrhoea during registration were more likely to have cholera. Females and individuals reporting diarrhoea during registration were at increased risk of CSD. Among population 3, individuals living in a household without a concrete floor, in an area with high population density, closer to the study hospital, or not treating drinking water were at significantly higher risk for both cholera and CSD.

CONCLUSION

The profile of socioeconomic factors associated with cholera varies by individuals' vaccination status as well as the transmission setting. In a vaccinated community where transmission would be expected to be lower, socioeconomic factors may not increase the risk of the disease.

Safety of the oral cholera vaccine in pregnancy: Retrospective findings from a subgroup following mass vaccination campaign in Dhaka, Bangladesh

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Few women received the OCV unknowingly while pregnant during a large vaccine trial.

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There is limited data on the safety of OCVs in pregnancy.

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We evaluated the effect of a killed OCV, Shanchol™, on pregnancy outcomes.

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Study showed no evidence of exposure to Shanchol™ on adverse pregnancy outcomes.

Background

Pregnant women are vulnerable to complications of cholera. Killed oral cholera vaccines (OCV) are not recommended for pregnant women though there is no evidence of harmful effects during pregnancy. We evaluated the effect of a killed OCV, Shanchol™, on pregnancy outcomes during an effectiveness trial of the vaccine in urban Bangladesh.

Methodology

Individuals ⩾1 year were invited to participate in the trial, conducted in 2011 in Dhaka, Bangladesh. Pregnancy by history was an exclusion criterion and all women of reproductive age (15–49 years) were verbally questioned about pregnancy at enrollment and prior to vaccination. Out of 48,414 women of reproductive age 286 women received the OCV unknowingly while pregnant. Out of these, we could recruit 69 women defined as exposed to OCV. Accordingly, we selected 69 pregnant women randomly from those who did not take the OCV (non-exposed to OCV). We evaluated adverse pregnancy outcome (spontaneous miscarriages, still births, or congenital malformations) between those who were exposed to OCV and those who were not exposed to OCV.

Results

About 16% of pregnant women exposed to OCV had pregnancy loss, as compared to 12% of unvaccinated pregnant women (P = 0.38). One congenital anomaly was observed and occurred in women non-exposed to OCV group. Models that adjusted for baseline characteristics that were unbalanced between the exposed and non-exposed groups, revealed a no elevation of risk of adverse pregnancy outcomes in vaccinees versus non-vaccinees (Adj. OR (95% CI): 0.45 (0.11–1.88).

Conclusions

No excess of adverse fetal outcomes associated with receipt of OCV was observed in this study.

Trial registration: Clinical Trials.gov number NCT01339845.

Use of Oral Cholera Vaccine and Knowledge, Attitudes, and Practices Regarding Safe Water, Sanitation and Hygiene in a Long-Standing Refugee Camp, Thailand, 2012-2014

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.

Safe water, sanitation, and hygiene (WaSH) are the primary measures for cholera prevention and control. Since 2010, oral cholera vaccines (OCVs) have been recommended as an additional tool for endemic and epidemic cholera prevention and control. Given the relatively new use of OCVs in public health programs, there is limited information on the impact of OCV use on traditional WaSH activities, i.e., can they serve as complementary tools, or will OCV use have a negative impact on WaSH-related behaviors? This study reports the findings of knowledge, attitudes and practices (KAP) surveys conducted before and after a preventive OCV campaign (2013) in a long-standing refugee camp in Thailand, where frequent cholera outbreaks had occurred in recent years. The surveys demonstrated high acceptability of the OCV campaign and several modest improvements in cholera and WaSH KAPs among the camp population. OCV campaigns may be used as opportunities to reinforce cholera and WaSH-related messaging towards strengthening comprehensive cholera prevention and control.

Oral Cholera Vaccination Delivery Cost in Low- and Middle-Income Countries: An Analysis Based on Systematic Review

BACKGROUND

Use of the oral cholera vaccine (OCV) is a vital short-term strategy to control cholera in endemic areas with poor water and sanitation infrastructure. Identifying, estimating, and categorizing the delivery costs of OCV campaigns are useful in analyzing cost-effectiveness, understanding vaccine affordability, and in planning and decision making by program managers and policy makers.

OBJECTIVES

To review and re-estimate oral cholera vaccination program costs and propose a new standardized categorization that can help in collation, analysis, and comparison of delivery costs across countries.

DATA SOURCES

Peer reviewed publications listed in PubMed database, Google Scholar and World Health Organization (WHO) websites and unpublished data from organizations involved in oral cholera vaccination.

STUDY ELIGIBILITY CRITERIA

The publications and reports containing oral cholera vaccination delivery costs, conducted in low- and middle-income countries based on World Bank Classification. Limits are humans and publication date before December 31st, 2014.

PARTICIPANTS

No participants are involved, only costs are collected.

INTERVENTION

Oral cholera vaccination and cost estimation.

STUDY APPRAISAL AND SYNTHESIS METHOD

A systematic review was conducted using pre-defined inclusion and exclusion criteria. Cost items were categorized into four main cost groups: vaccination program preparation, vaccine administration, adverse events following immunization and vaccine procurement; the first three groups constituting the vaccine delivery costs. The costs were re-estimated in 2014 US dollars (US$) and in international dollar (I$).

RESULTS

Ten studies were identified and included in the analysis. The vaccine delivery costs ranged from US$0.36 to US$ 6.32 (in US$2014) which was equivalent to I$ 0.99 to I$ 16.81 (in I$2014). The vaccine procurement costs ranged from US$ 0.29 to US$ 29.70 (in US$2014), which was equivalent to I$ 0.72 to I$ 78.96 (in I$2014). The delivery costs in routine immunization systems were lowest from US$ 0.36 (in US$2014) equivalent to I$ 0.99 (in I$2014).

LIMITATIONS

The reported cost categories are not standardized at collection point and may lead to misclassification. Costs for some OCV campaigns are not available and analysis does not include direct and indirect costs to vaccine recipients.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Vaccine delivery cost estimation is needed for budgeting and economic analysis of vaccination programs. The cost categorization methodology presented in this study is helpful in collecting OCV delivery costs in a standardized manner, comparing delivery costs, planning vaccination campaigns and informing decision-making.

Mobile clinics for women's and children's health

BACKGROUND

The accessibility of health services is an important factor that affects the health outcomes of populations. A mobile clinic provides a wide range of services but in most countries the main focus is on health services for women and children. It is anticipated that improvement of the accessibility of health services via mobile clinics will improve women's and children's health.

OBJECTIVES

To evaluate the impact of mobile clinic services on women's and children's health.

SEARCH METHODS

For related systematic reviews, we searched the Database of Abstracts of Reviews of Effectiveness (DARE), CRD; Health Technology Assessment Database (HTA), CRD; NHS Economic Evaluation Database (NHS EED), CRD (searched 20 February 2014).For primary studies, we searched ISI Web of Science, for studies that have cited the included studies in this review (searched 18 January 2016); WHO ICTRP, and ClinicalTrials.gov (searched 23 May 2016); Cochrane Central Register of Controlled Trials (CENTRAL), part of The Cochrane Library. www.cochranelibrary.com (including the Cochrane Effective Practice and Organisation of Care (EPOC) Group Specialised Register) (searched 7 April 2015); MEDLINE, OvidSP (searched 7 April 2015); Embase, OvidSP (searched 7 April 2015); CINAHL, EbscoHost (searched 7 April 2015); Global Health, OvidSP (searched 8 April 2015); POPLINE, K4Health (searched 8 April 2015); Science Citation Index and Social Sciences Citation Index, ISI Web of Science (searched 8 April 2015); Global Health Library, WHO (searched 8 April 2015); PAHO, VHL (searched 8 April 2015); WHOLIS, WHO (searched 8 April 2015); LILACS, VHL (searched 9 April 2015).

SELECTION CRITERIA

We included individual- and cluster-randomised controlled trials (RCTs) and non-RCTs. We included controlled before-and-after (CBA) studies provided they had at least two intervention sites and two control sites. Also, we included interrupted time series (ITS) studies if there was a clearly defined point in time when the intervention occurred and at least three data points before and three after the intervention. We defined the intervention of a mobile clinic as a clinic vehicle with a healthcare provider (with or without a nurse) and a driver that visited areas on a regular basis. The participants were women (18 years or older) and children (under the age of 18 years) in low-, middle-, and high-income countries.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of studies identified by the search strategy, extracted data from the included studies using a specially-designed data extraction form based on the Cochrane EPOC Group data collection checklist, and assessed full-text articles for eligibility. All authors performed analyses, 'Risk of bias' assessments, and assessed the quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Two cluster-RCTs met the inclusion criteria of this review. Both studies were conducted in the USA.One study tested whether offering onsite mobile mammography combined with health education was more effective at increasing breast cancer screening rates than offering health education only, including reminders to attend a static clinic for mammography. Women in the group offered mobile mammography and health education may be more likely to undergo mammography within three months of the intervention than those in the comparison group (55% versus 40%; odds ratio (OR) 1.83, 95% CI 1.22 to 2.74; low certainty evidence).A cost-effectiveness analysis of mammography at mobile versus static units found that the total cost per patient screened may be higher for mobile units than for static units. The incremental costs per patient screened for a mobile over a stationary unit were USD 61 and USD 45 for a mobile full digital unit and a mobile film unit respectively.The second study compared asthma outcomes for children aged two to six years who received asthma care from a mobile asthma clinic and children who received standard asthma care from the usual (static) primary provider. Children who receive asthma care from a mobile asthma clinic may experience little or no difference in symptom-free days, urgent care use and caregiver-reported medication use compared to children who receive care from their usual primary care provider. All of the evidence was of low certainty.

AUTHORS' CONCLUSIONS

The paucity of evidence and the restricted range of contexts from which evidence is available make it difficult to draw conclusions on the impacts of mobile clinics on women's and children's health compared to static clinics. Further rigorous studies are needed in low-, middle-, and high-income countries to evaluate the impacts of mobile clinics on women's and children's health.

Efficacy of a Single-Dose, Inactivated Oral Cholera Vaccine in Bangladesh

BACKGROUND

A 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.

METHODS

Nonpregnant 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.

RESULTS

A total of 101 episodes of cholera, 37 associated with severe dehydration, were detected among the 204,700 persons who received one dose of vaccine or placebo. The vaccine protective efficacy was 40% (95% confidence interval [CI], 11 to 60%; 0.37 cases per 1000 vaccine recipients vs. 0.62 cases per 1000 placebo recipients) against all cholera episodes, 63% (95% CI, 24 to 82%; 0.10 vs. 0.26 cases per 1000 recipients) against severely dehydrating cholera episodes, and 63% (95% CI, -39 to 90%), 56% (95% CI, 16 to 77%), and 16% (95% CI, -49% to 53%) against all cholera episodes among persons vaccinated at the age of 5 to 14 years, 15 or more years, and 1 to 4 years, respectively, although the differences according to age were not significant (P=0.25). Adverse events occurred at similar frequencies in the two groups.

CONCLUSIONS

A single dose of the oral cholera vaccine was efficacious in older children (≥5 years of age) and in adults in a setting with a high level of cholera endemicity. (Funded by the Bill and Melinda Gates Foundation and others; ClinicalTrials.gov number, NCT02027207.).

The oral cholera vaccine Shanchol™ when stored at elevated temperatures maintains the safety and immunogenicity profile in Bangladeshi participants

BACKGROUND

The oral cholera vaccine (OCV), Shanchol™ has shown protective efficacy lasting up to 5 years, however, requirement for a cold chain limits its use in resource poor settings. The study was conducted to determine the safety and immunogenicity of Shanchol in adult participants in Bangladesh when stored at elevated temperatures.

METHODS

The study was conducted in Mirpur, Dhaka. Four groups of healthy adult participants received two doses of Shanchol™, kept under standard storage temperature (Group A; 2-8°C) or at elevated temperatures (Group B, 25°C; Group C, 37°C; Group D, 42°C) for 14 days, respectively. Vaccine specific antibody responses were determined.

FINDINGS

145 participants were assigned to each group. Adverse events were mild not differing among groups. Vaccine stored at elevated temperatures remained stable with cumulative LPS content within admissible limits. Vibriocidal antibody responses were observed in all groups after each dose of vaccine at day 7 and 21 compared to pre-immune levels (P<0.001). Four-fold increases to Vibrio cholerae O1 Ogawa were observed at day 7 and/or day 21 after vaccination in the standard temperature and the three elevated temperature groups, with responder rates of; 76% (95% CI LB; 70%), 80% (95% CI LB; 74%), 69% (95% CI LB; 63%), and 74% (95% CI LB; 68%) in Groups A-D, respectively (P=0.240). Responses were also seen in all groups to V. cholerae O1 Inaba and V. cholerae O139 and in LPS specific IgA response to V. cholerae O1 antigens.

INTERPRETATION

This is the first report to show that the OCV is stable at elevated temperatures, and the safety and immunogenicity profiles are not altered. This information will help formulate global policies for use of the vaccine at higher temperatures, resulting in easier distribution and vaccination costs and decrease logistical challenges to vaccine delivery.

FUNDING

Bill & Melinda Gates Foundation.

TRIAL REGISTRATION

Clinical Trials.gov number NCT01762930.

Vibrio cholerae Serogroup O139: Isolation from Cholera Patients and Asymptomatic Household Family Members in Bangladesh between 2013 and 2014

Background

Cholera is endemic in Bangladesh, with outbreaks reported annually. Currently, the majority of epidemic cholera reported globally is El Tor biotype Vibrio cholerae isolates of the serogroup O1. However, in Bangladesh, outbreaks attributed to V. cholerae serogroup O139 isolates, which fall within the same phylogenetic lineage as the O1 serogroup isolates, were seen between 1992 and 1993 and in 2002 to 2005. Since then, V. cholerae serogroup O139 has only been sporadically isolated in Bangladesh and is now rarely isolated elsewhere.

Methods

Here, we present case histories of four cholera patients infected with V. cholerae serogroup O139 in 2013 and 2014 in Bangladesh. We comprehensively typed these isolates using conventional approaches, as well as by whole genome sequencing. Phenotypic typing and PCR confirmed all four isolates belonging to the O139 serogroup.

Findings

Whole genome sequencing revealed that three of the isolates were phylogenetically closely related to previously sequenced El Tor biotype, pandemic 7, toxigenic V. cholerae O139 isolates originating from Bangladesh and elsewhere. The fourth isolate was a non-toxigenic V. cholerae that, by conventional approaches, typed as O139 serogroup but was genetically divergent from previously sequenced pandemic 7 V. cholerae lineages belonging to the O139 or O1 serogroups.

Conclusion

These results suggest that previously observed lineages of V. cholerae O139 persist in Bangladesh and can cause clinical disease and that a novel disease-causing non-toxigenic O139 isolate also occurs.

Vibrio cholerae serogroup O1 is thought to be the sole causative agent for cholera in Bangladesh and most of the high risk developing countries. Whilst historically Vibrio cholerae serogroup O139 has been seen to cause sporadic disease, the overall numbers of reported O139 clinical cases are low, with none reported in Bangladesh since 2005. Here we report four patients suffering from cholera attributed to serogroup O139 V. cholerae. Cases 1 and 2 were symptomatic (isolated strains 1, 2), and cases 3 and 4 were asymptomatic (isolated strains 3, 4). All cases were from urban Dhaka and represented a range of age groups. Cases 2–4 presented with no sign of dehydration whereas case 1 showed some signs of dehydration. Phenotypic and whole genome sequence data indicates that one of the four O139 V. cholerae isolates represents a novel O139 subtype. Since natural infection with V. cholerae O1 or vaccination with currently available licensed cholera vaccines (e.g., Dukoral) provides little protection against O139, we conclude that V. cholerae O139 remains in circulation and is still causing a low incidence of cholera. Therefore, further studies looking at the significance of these isolates towards the total burden of cholera in Bangladesh is warranted, including clinical evaluation, genome sequencing and immunobiochemistry.

Feasibility and effectiveness of oral cholera vaccine in an urban endemic setting in Bangladesh: a cluster randomised open-label trial

BACKGROUND

Cholera is endemic in Bangladesh with epidemics occurring each year. The decision to use a cheap oral killed whole-cell cholera vaccine to control the disease depends on the feasibility and effectiveness of vaccination when delivered in a public health setting. We therefore assessed the feasibility and protective effect of delivering such a vaccine through routine government services in urban Bangladesh and evaluated the benefit of adding behavioural interventions to encourage safe drinking water and hand washing to vaccination in this setting.

METHODS

We did this cluster-randomised open-label trial in Dhaka, Bangladesh. We randomly assigned 90 clusters (1:1:1) to vaccination only, vaccination and behavioural change, or no intervention. The primary outcome was overall protective effectiveness, assessed as the risk of severely dehydrating cholera during 2 years after vaccination for all individuals present at time of the second dose. This study is registered with ClinicalTrials.gov, number NCT01339845.

FINDINGS

Of 268,896 people present at baseline, we analysed 267,270: 94,675 assigned to vaccination only, 92,539 assigned to vaccination and behavioural change, and 80,056 assigned to non-intervention. Vaccine coverage was 65% in the vaccination only group and 66% in the vaccination and behavioural change group. Overall protective effectiveness was 37% (95% CI lower bound 18%; p=0·002) in the vaccination group and 45% (95% CI lower bound 24%; p=0·001) in the vaccination and behavioural change group. We recorded no vaccine-related serious adverse events.

INTERPRETATION

Our findings provide the first indication of the effect of delivering an oral killed whole-cell cholera vaccine to poor urban populations with endemic cholera using routine government services and will help policy makers to formulate vaccination strategies to reduce the burden of severely dehydrating cholera in such populations.

FUNDING

Bill & Melinda Gates Foundation.

An Estimation of Private Household Costs to Receive Free Oral Cholera Vaccine in Odisha, India

BACKGROUND

Service provider costs for vaccine delivery have been well documented; however, vaccine recipients' costs have drawn less attention. This research explores the private household out-of-pocket and opportunity costs incurred to receive free oral cholera vaccine during a mass vaccination campaign in rural Odisha, India.

METHODS

Following a government-driven oral cholera mass vaccination campaign targeting population over one year of age, a questionnaire-based cross-sectional survey was conducted to estimate private household costs among vaccine recipients. The questionnaire captured travel costs as well as time and wage loss for self and accompanying persons. The productivity loss was estimated using three methods: self-reported, government defined minimum daily wages and gross domestic product per capita in Odisha.

FINDINGS

On average, families were located 282.7 (SD = 254.5) meters from the nearest vaccination booths. Most family members either walked or bicycled to the vaccination sites and spent on average 26.5 minutes on travel and 15.7 minutes on waiting. Depending upon the methodology, the estimated productivity loss due to potential foregone income ranged from $0.15 to $0.29 per dose of cholera vaccine received. The private household cost of receiving oral cholera vaccine constituted 24.6% to 38.0% of overall vaccine delivery costs.

INTERPRETATION

The private household costs resulting from productivity loss for receiving a free oral cholera vaccine is a substantial proportion of overall vaccine delivery cost and may influence vaccine uptake. Policy makers and program managers need to recognize the importance of private costs and consider how to balance programmatic delivery costs with private household costs to receive vaccines.

Estimating the cost of cholera-vaccine delivery from the societal point of view: A case of introduction of cholera vaccine in Bangladesh

Cholera is a major global public health problem that causes both epidemic and endemic disease. The World Health Organization recommends oral cholera vaccines as a public health tool in addition to traditional prevention practices and treatments in both epidemic and endemic settings. In many developing countries like Bangladesh, the major issue concerns the affordability of this vaccine. In February 2011, a feasibility study entitled, "Introduction of Cholera Vaccine in Bangladesh (ICVB)", was conducted for a vaccination campaign using inactivated whole-cell cholera vaccine (Shanchol) in a high risk area of Mirpur, Dhaka. Empirical data obtained from this trial was used to determine the vaccination cost for a fully immunized person from the societal perspective. A total of 123,661 people were fully vaccinated receiving two doses of the vaccine, while 18,178 people received one dose of the same vaccine. The total cost for vaccine delivery was US$ 492,238 giving a total vaccination cost per fully-vaccinated individual of US$ 3.98. The purchase cost of the vaccine accounted for 58% of the overall cost of vaccination. Attempts to reduce the per-dose cost of the vaccine are likely to have a large impact on the cost of similar vaccination campaigns in the future.