https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(04)17481-3.pdf

Communicable diseases in complex emergencies: impact and challenges.

Background New-generation, orally administered cholera vaccines offer the promise of improved control of cholera in sub-Saharan Africa. However, the high prevalence of human immunodeficiency virus (HIV) infection in many cholera-affected African populations has raised doubts about the level of protection possible with vaccination. We evaluated a mass immunization program with recombinant cholera-toxin B subunit, killed whole-cell (rBS-WC) oral cholera vaccine in Beira, Mozambique, a city where the seroprevalence of HIV is 20 to 30 percent. Methods From December 2003 to January 2004, we undertook mass immunization of nonpregnant persons at least two years of age, using a two-dose regimen of rBS-WC vaccine in Esturro, Beira (population 21,818). We then assessed vaccine protection in a case–control study during an outbreak of El Tor Ogawa cholera in Beira between January and May 2004. To estimate the level of vaccine protection, antecedent rates of vaccination were compared between persons with culture-confi...

/pdf/effectiveness-of-mass-oral-cholera-vaccination-in-beira-55d4x21mo0.pdf

Effectiveness of Mass Oral Cholera Vaccination in Beira, Mozambique

Cholera is a substantial health burden on the developing world and is endemic in Africa, Asia, South America, and Central America. The exact scale of the problem is uncertain because of limitations in existing surveillance systems, differences in reporting procedures, and failure to report cholera to WHO; official figures are likely to greatly underestimate the true prevalence of the disease. We have identified, through extensive literature searches, additional outbreaks of cholera to those reported to WHO, many of which originated from the Indian subcontinent and southeast Asia. Such underestimation of cholera can have important implications for decisions on provision of health interventions for indigenous populations, and on risk assessments for travellers. Furthermore, until recently, it has not been possible to implement public-health interventions in low-income countries to eliminate disease, and the prevention of cholera in travellers has been limited to restrictive guidelines. However, a vaccine against cholera is now available that has proven efficacy and tolerability in mass vaccination campaigns in low-income countries, and among travellers.

https://www.thelancet.com/pdfs/journals/laninf/PIIS1473-3099(07)70138-X.pdf

The true burden and risk of cholera: implications for prevention and control

Background Although advances in rehydration therapy have made cholera a treatable disease with low case-fatality in settings with appropriate medical care, cholera continues to impose considerable mortality in the world’s most impoverished populations. Internationally licensed, killed whole-cell based oral cholera vaccines (OCVs) have been available for over a decade, but have not been used for the control of cholera. Recently, these vaccines were shown to confer significant levels of herd protection, suggesting that the protective potential of these vaccines has been underestimated and that these vaccines may be highly effective in cholera control when deployed in mass immunization programs. We used a large-scale stochastic simulation model to investigate the possibility of controlling endemic cholera with OCVs. Methods and Findings We construct a large-scale, stochastic cholera transmission model of Matlab, Bangladesh. We find that cholera transmission could be controlled in endemic areas with 50% coverage with OCVs. At this level of coverage, the model predicts that there would be an 89% (95% confidence interval [CI] 72%–98%) reduction in cholera cases among the unvaccinated, and a 93% (95% CI 82%–99%) reduction overall in the entire population. Even a more modest coverage of 30% would result in a 76% (95% CI 44%–95%) reduction in cholera incidence for the population area covered. For populations that have less natural immunity than the population of Matlab, 70% coverage would probably be necessary for cholera control, i.e., an annual incidence rate of � 1 case per 1,000 people in the population.

/pdf/controlling-endemic-cholera-with-oral-vaccines-ebbsii6ksb.pdf

Controlling Endemic Cholera with Oral Vaccines

In October 2010, a virulent South Asian strain of El Tor cholera began to spread in Haiti. Interventions have included treatment of cases and improved sanitation. Use of cholera vaccines would likely have further reduced morbidity and mortality, but such vaccines are in short supply and little is known about effective vaccination strategies for epidemic cholera. We use a mathematical cholera transmission model to assess different vaccination strategies. With limited vaccine quantities, concentrating vaccine in high-risk areas is always most efficient. We show that targeting one million doses of vaccine to areas with high exposure to Vibrio cholerae, enough for two doses for 5% of the population, would reduce the number of cases by 11%. The same strategy with enough vaccine for 30% of the population with modest hygienic improvement could reduce cases by 55% and save 3,320 lives. For epidemic cholera, we recommend a large mobile stockpile of enough vaccine to cover 30% of a country's population to be reactively targeted to populations at high risk of exposure.

https://www.pnas.org/content/pnas/108/17/7081.full.pdf

Vaccination strategies for epidemic cholera in Haiti with implications for the developing world

In refugee settings, the use of cholera vaccines is controversial since a mass vaccination campaign might disrupt other priority interventions. We therefore conducted a study to assess the feasibility of such a campaign using a two-dose oral cholera vaccine in a refugee camp. The campaign, using killed whole-cell/recombinant B-subunit cholera vaccine, was carried out in October 1997 among 44,000 south Sudanese refugees in Uganda. Outcome variables included the number of doses administered, the drop-out rate between the two rounds, the proportion of vaccine wasted, the speed of administration, the cost of the campaign, and the vaccine coverage. Overall, 63,220 doses of vaccine were administered. At best, 200 vaccine doses were administered per vaccination site and per hour. The direct cost of the campaign amounted to US$ 14,655, not including the vaccine itself. Vaccine coverage, based on vaccination cards, was 83.0% and 75.9% for the first and second rounds, respectively. Mass vaccination of a large refugee population with an oral cholera vaccine therefore proved to be feasible. A pre-emptive vaccination strategy could be considered in stable refugee settings and in urban slums in high-risk areas. However, the potential cost of the vaccine and the absence of quickly accessible stockpiles are major drawbacks for its large-scale use.

Mass vaccination with a two-dose oral cholera vaccine in a refugee camp.

Sir -- Further to the mass cholera vaccination campaign in refugee camps in Adjumani district, Northern Region, Uganda, reported in the last issue of the Bulletin (1), we describe below the situation when a cholera outbreak occurred in the district one year after the campaign. Adjumani district has offered asylum to Sudanese refugees since 1989. The refugee population, which represents about 55% of the total district population (125 000 people), is spread over 35 different settlement camps. At the request of WHO, a pilot vaccination campaign with the WC/rBS oral cholera vaccine was conducted in October 1997 in six of these camps. The objective was to assess the feasibility and acceptability of mass vaccination in a large refugee setting (2). Vaccine coverage was 87.0%, a total of 27 607 persons being fully vaccinated. A cholera epidemic caused by Vibrio cholerae El Tor serotype Ogawa reached the north of Uganda in April 1998. In Adjumani district the first cases of cholera were reported in August, and the epidemic peaked in October 1998. Between 17 August and 8 November, 358 cases of cholera were reported from 60 different locations covering the entire district. The overall attack rate was 0.3% and the case-fatality ratio was 4.2% (15 deaths). The epidemic affected the entire district, and all the refugees, including those living in the vaccinated camps, were exposed to the risk of cholera. A total of 28 cases out of 358 (7.8%) occurred among refugees, but none of them came from a settlement that participated in the vaccination campaign in 1997. Attack rates were higher in the Ugandan population than in the refugee population (0.59% v 0.04%, relative risk: 14.4 (95% confidence interval, 9.8-21.2)). Water supplies and sanitation facilities were similar in the vaccinated and non-vaccinated settlements, but were better in the settlements than in the Ugandan villages. This fact might partly explain the lower attack rate observed in the refugee population. Since no case of cholera was reported from the vaccinated population, it was not possible to measure vaccine effectiveness using classic epidemiological studies (3). Therefore, in order to assess whether the cholera vaccination had had a protective effect, we compared the global incidences of common (non-bloody) diarrhoea between vaccinated and non-vaccinated refugee settlements for the month of October 1998. We also compiled the evolution of common diarrhoea incidences in four vaccinated settlements over the period October 1997 (vaccination) to October 1998 (outbreak). The median incidences of common diarrhoea in October 1998 were lower in the vaccinated settlements (2.8/1000) compared with non-vaccinated settlements (10.0/1000) and the Ugandan population (4.3/1000) attending the same health units, but the differences were not statistically significant. The trends in the common diarrhoea incidences since October 1997 in four vaccinated camps did not show any marked increase during the cholera epidemic period (Fig. …

Effectiveness of mass vaccination with WC/rBS cholera vaccine during an epidemic in Adjumani district, Uganda.

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

B. Ivanoff

Author Tools

Chat about Author

Papers

Mass vaccination with a two-dose oral cholera vaccine in a refugee camp.

Effectiveness of mass vaccination with WC/rBS cholera vaccine during an epidemic in Adjumani district, Uganda.