Feasibility of a mass vaccination campaign using a two-dose oral cholera vaccine in an urban cholera-endemic setting in Mozambique.

We conducted a study to assess the feasibility and the potential vaccine coverage of a mass vaccination campaign using a two-dose oral cholera vaccine in an urban endemic neighbourhood of Beira, Mozambique. The campaign was conducted from December 2003 to January 2004. Overall 98,152 doses were administered, and vaccine coverage of the target population was 58.

The burden of diarrhoea, shigellosis, and cholera in North Jakarta, Indonesia: findings from 24 months surveillance.

Background: In preparation of vaccines trials to estimate protection against shigellosis and cholera we conducted a two-year community-based surveillance study in an impoverished area of North Jakarta which provided updated information on the disease burden in the area.

Methods: We conducted a two-year community-based surveillance study from August 2001 to July 2003 in an impoverished area of North Jakarta to assess the burden of diarrhoea, shigellosis, and cholera. At participating health care providers, a case report form was completed and stool sample collected from cases presenting with diarrhoea.

The use of a computerized database to monitor vaccine safety in Viet Nam.

Health information systems to monitor vaccine safety are used in industrialized countries to detect adverse medical events related to vaccinations or to prove the safety of vaccines. There are no such information systems in the developing world, but they are urgently needed. A large linked database for the monitoring of vaccine-related adverse events has been established in Khanh Hoa province, Viet Nam.

Efficacy of a locally produced, Chinese Vi polysaccharide typhoid fever vaccine during six years of follow-up.

A locally produced Vi polysaccharide vaccine against typhoid fever was licensed in China following two placebo-controlled, efficacy trials conducted in the early 1990s in Baoying, Jiangsu Province, and Quan-zhou, Guangxi Province. The two trials each enrolled over 80,000 participants and followed participants for 12 and 19 months post-vaccination, respectively. To define the long-term efficacy of this vaccine, we retrospectively assessed the occurrence of typhoid fever, diagnosed with clinical and serological criteria, in the two study populations for 6 years following vaccination.

Randomized, controlled study of the safety and immunogenicity of Peru-15, a live attenuated oral vaccine candidate for cholera, in adult volunteers in Bangladesh.

A live oral Vibrio cholerae O1 El Tor vaccine candidate, Peru-15, was studied for safety, immunogenicity, and excretion in phase 1 (inpatient) and phase 2 (outpatient) studies of Bangladeshi adults.METHODs. The study was conducted among adults, by use of a double-blind, randomized, placebo-controlled design.

Herd immunity conferred by killed oral cholera vaccines in Bangladesh: a reanalysis.

Background: Decisions about the use of killed oral cholera vaccines, which confer moderate levels of direct protection to vaccinees, can depend on whether the vaccines also provide indirect (herd) protection when high levels of vaccine coverage are attained. We reanalysed data from a field trial in Bangladesh to ascertain whether there is evidence of indirect protection from killed oral cholera vaccines.

Methods: We analysed the first year of surveillance data from a placebo-controlled trial of B subunit-killed whole-cell and killed whole-cell-only oral cholera vaccines in children and adult women in Bangladesh.

Pandemic serovars (O3:K6 and O4:K68) of Vibrio parahaemolyticus associated with diarrhea in Mozambique: spread of the pandemic into the African continent.

Forty-two episodes of Vibrio parahaemolyticus infections were detected in Beira, Mozambique, from January to May 2004. The majority of the isolates (81%) belonged to the pandemic serovars (O3:K6 and O4:K68) of V. parahaemolyticus.

Neighborhood size and local geographic variation of health and social determinants.

BACKGROUND: Spatial filtering using a geographic information system (GIS) is often used to smooth health and ecological data. Smoothing disease data can help us understand local (neighborhood) geographic variation and ecological risk of diseases. Analyses that use small neighborhood sizes yield individualistic patterns and large sizes reveal the global structure of data where local variation is obscured.

A mass vaccination campaign targeting adults and children to prevent typhoid fever in Hechi; expanding the use of Vi polysaccharide vaccine in southeast China: a cluster-randomized trial.

Background: One of the goals of this study was to learn the coverage, safety and logistics of a mass vaccination campaign against typhoid fever in children and adults using locally produced typhoid Vi polysaccharide (PS) and group A meningococcal PS vaccines in southern China.

Methods: The vaccination campaign targeted 118,588 persons in Hechi, Guangxi Province, aged between 5 to 60 years, in 2003. The study area was divided into 107 geographic clusters, which were randomly allocated to receive one of the single-dose parenteral vaccines.

Policymakers' views regarding the introduction of new-generation vaccines against typhoid fever, shigellosis and cholera in Asia.

Face-to-face interviews and meetings with more than 160 policymakers and other influential professionals in seven large Asian countries (Bangladesh, China, India, Indonesia, Pakistan, Thailand and Vietnam) were conducted to survey opinions regarding the need for, and potential uses of new-generation vaccines against cholera, typhoid fever and shigellosis. Despite several barriers to their uptake--notably uncertainty of the burden of enteric diseases; preference for water, sanitation and other environmental improvements over vaccination for disease control; and high prices of the current vaccines relative to basic EPI vaccines, and their moderate protection levels--considerable interest was found in the targeted use of Vi typhoid vaccine in most countries, followed by (future) Shigella and oral cholera vaccines. The introduction of these vaccines in Asia could be greatly facilitated by country-specific evidence of disease burden, local or regional vaccine production, field studies demonstrating their safety and efficacy in local populations, evidence of potential economic savings from vaccination, and effective dissemination of research results to all those who make or influence immunization policy.

Effectiveness of mass oral cholera vaccination in Beira, Mozambique.

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.

Serologic correlates of protection against enterotoxigenic Escherichia coli diarrhea.

Background: We conducted a nested case-control study in 397 rural Egyptian children <36 months of age to assess the correlation between serum levels of antibodies against toxin and colonization factors (CFs) and the risk of homologous enterotoxigenic Escherichia coli (ETEC) diarrhea.

Methods: Active case detection was performed via semiweekly home visits, and blood was obtained at 3-month intervals. After each serosurvey, case subjects were selected from children experiencing a CF antigen (CFA)/I-, CFA/II-, CFA/IV-, or heat-labile enterotoxin (LT)-ETEC diarrheal episode during the subsequent 3 months.

A cost-benefit analysis of typhoid fever immunization programmes in an Indian urban slum community.

Many economic analyses of immunization programmes focus on the benefits in terms of public-sector cost savings, but do not incorporate estimates of the private cost savings that individuals receive from vaccination. This paper considers the implications of Bahl et al.'s cost-of-illness estimates for typhoid immunization policy by examining how community-level incidence estimates and information on distribution of costs of illness among patients and the public-health sector can be used in the economic analysis of vaccination-programme options.

Costs of illness due to typhoid fever in an Indian urban slum community: implications for vaccination policy.

Data on the burden of disease, costs of illness, and cost-effectiveness of vaccines are needed to facilitate the use of available anti-typhoid vaccines in developing countries. This one-year prospective surveillance was carried out in an urban slum community in Delhi, India, to estimate the costs of illness for cases of typhoid fever. Ninety-eight culture-positive typhoid, 31 culture-positive paratyphoid, and 94 culture-negative cases with clinical typhoid syndrome were identified during the surveillance.

The role of epidemiology in the introduction of vi polysaccharide typhoid fever vaccines in Asia.

Despite the availability of at least two licensed typhoid fever vaccines--injectable sub-unit Vi polysaccharide vaccine and live, oral Ty21a vaccine--for the last decade, these vaccines have not been widely introduced in public-health programmes in countries endemic for typhoid fever. The goal of the multidisciplinary DOMI (Diseases of the Most Impoverished) typhoid fever programme is to generate policy-relevant data to support public decision-making regarding the introduction of Vi polysaccharide typhoid fever immunization programmes in China, Viet Nam, Pakistan, India, Bangladesh, and Indonesia. Through epidemiological studies, the DOMI Programme is generating these data and is offering a model for the accelerated, rational introduction of new vaccines into health programmes in low-income countries.

Multidisciplinary studies of disease burden in the Diseases of the Most Impoverished Programme.

With limited healthcare resources, rational prioritization of healthcare interventions requires knowledge and analysis of disease burden. In the absence of actual disease-burden data from less-developed countries, various types of morbidity and mortality estimates have been made. Besides having questionable reliability, these estimates do not capture the full burden of a disease since they provide only the number of cases and deaths.

Translational research to assist policy decisions about introducing new vaccines in developing countries.

Few new-generation vaccines have found their way into public-health programmes for the poor in developing countries, and for those that have, delays of years or even decades after their licensure and introduction in industrialized countries have been the rule. Financial constraints and political obstacles have played major roles in delaying the introduction of the vaccines. Also contributing to this situation has been a dearth of needed research.

Phenotypic profiles of enterotoxigenic Escherichia coli associated with early childhood diarrhea in rural Egypt.

Enterotoxigenic Escherichia coli (ETEC) causes substantial diarrheal morbidity and mortality in young children in countries with limited resources. We determined the phenotypic profiles of 915 ETEC diarrheal isolates derived from Egyptian children under 3 years of age who participated in a 3-year population-based study. For each strain, we ascertained enterotoxin and colonization factor (CF) expression, the O:H serotype, and antimicrobial susceptibility.

Healthcare use for diarrhoea and dysentery in actual and hypothetical cases, Nha Trang, Viet Nam.

To better understand healthcare use for diarrhoea and dysentery in Nha Trang, Viet Nam, qualitative interviews with community residents and dysentery case studies were conducted. Findings were supplemented by a quantitative survey which asked respondents which healthcare provider their household members would use for diarrhoea or dysentery. A clear pattern of healthcare-seeking behaviours among 433 respondents emerged.

Factors associated with reported diarrhoea episodes and treatment-seeking in an urban slum of Kolkata, India.

In an urban slum in eastern Kolkata, India, reported diarrhoea rates, healthcare-use patterns, and factors associated with reported diarrhoea episodes were studied as a part of a diarrhoea-surveillance project. Data were collected through a structured interview during a census and healthcare-use survey of an urban slum population in Kolkata. Several variables were analyzed, including (a) individual demographics, such as age and educational level, (b) household characteristics, such as number of household members, religious affiliation of the household head, building material, expenditure, water supply and sanitation, and (c) behaviour, such as hand-washing after defecation and healthcare use.

Diarrhoea episodes and treatment-seeking behaviour in a slum area of North Jakarta, Indonesia.

Visits to household during a census in an impoverished area of north Jakarta were used for exploring the four-week prevalence of diarrhoea, factors associated with episodes of diarrhoea, and the patterns of healthcare use. For 160,261 urban slum-dwellers, information was collected on the socioeconomic status of the household and on diarrhoea episodes of individual household residents in the preceding four weeks. In households with a reported case of diarrhoea, the household head was asked which form of healthcare was used first.

Preferences for treatment of diarrhoea and dysentery in Kaengkhoi district, Saraburi province, Thailand.

To estimate the proportion of cases missed in a passive surveillance study of diarrhoea and dysentery at health centres and hospitals in Kaengkhoi district, Saraburi province, Thailand, a community-based cluster survey of treatment-seeking behaviours was conducted during 21-23 June 2002. Interviews were conducted at 224 households among a study population of 78,744. The respondents reported where they sought care for diarrhoea and dysentery in children aged less than five years and adults aged over 15 years.

A community-based cluster survey on preferences for treatment of diarrhoea and dysentery in Zhengding county, Hebei province, China.

Passive surveillance on the burden of disease due to diarrhoea will underestimate the burden if families use healthcare providers outside the surveillance system. To study this issue, a community-based cluster survey was conducted during October 2001 in the catchment area for a passive surveillance study in Zhengding county, a rural area of northern China. Interviews were conducted at 7 randomly-selected households in each of 39 study villages.