Haemophilus influenzae type B meningitis among children in Hanoi, Vietnam: epidemiologic patterns and estimates of H. Influenzae type B disease burden.

From March 2000 to February 2002, a population-based study of Haemophilus influenzae type b (Hib) meningitis was conducted among children less than five years of age in Hanoi, Vietnam. Children with suspected bacterial meningitis were referred to hospitals and each patient underwent standardized clinical examination and microbiologic testing. In Hanoi, 580 children were evaluated for bacterial meningitis and 23 (4%) had confirmed or probable Hib meningitis.

Enhanced disease surveillance through private health care sector cooperation in Karachi, Pakistan: experience from a vaccine trial.

Introduction: In research projects such as vaccine trials, accurate and complete surveillance of all outcomes of interest is critical. In less developed countries where the private sector is the major health-care provider, the private sector must be included in surveillance systems in order to capture all disease of interest. This, however, poses enormous challenges in practice.

The malaria and typhoid fever burden in the slums of Kolkata, India: data from a prospective community-based study.

Recent research has indicated that the malaria burden in Asia may have been vastly underestimated. We conducted a prospective community-based study in an impoverished urban site in Kolkata, India, to estimate the burden of malaria and typhoid fever and to identify risk factors for these diseases. In a population of 60452 people, 3605 fever episodes were detected over a 12-month period.

Field evaluation of a rapid immunochromatographic dipstick test for the diagnosis of cholera in a high-risk population.

Background: Early detection of cholera outbreaks is crucial for the implementation of the most appropriate control strategies.

Methods: The performance of an immunochromatographic dipstick test (Institute Pasteur, Paris, France) specific for Vibrio cholerae O1 was evaluated in a prospective study in Beira, Mozambique, during the 2004 cholera season (January-May). Fecal specimens were collected from 391 patients with acute watery nonbloody diarrhea and tested by dipstick and conventional culture.

Consecutive outbreaks of Vibrio cholerae O139 and V. cholerae O1 cholera in a fishing village near Karachi, Pakistan.

In July 2002 and June 2003, cholera outbreaks were detected by a diarrhoea surveillance system in a village outside Karachi, Pakistan. Specimens were culture confirmed. The first outbreak was caused by Vibrio cholerae O139 (n = 30) and the second outbreak by V.

Multilocus sequence typing (MLST) analysis of Vibrio cholerae O1 El Tor isolates from Mozambique that harbour the classical CTX prophage.

Vibrio cholerae O1 isolates belonging to the Ogawa serotype, El Tor biotype, harbouring the classical CTX prophage were first isolated in Mozambique in 2004. Multilocus sequence typing (MLST) analysis using nine genetic loci showed that the Mozambique isolates have the same sequence type (ST) as O1 El Tor N16961, a representative of the current seventh cholera pandemic. Analysis of the CTX prophage in the Mozambique isolates indicated that there is one type of rstR in these isolates: the classical CTX prophage.

Salmonella paratyphi A rates, Asia.

Little is known about the causes of enteric fever in Asia. Most cases are believed to be caused by Salmonella enterica serovar Typhi and the remainder by S. Paratyphi A.

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.