Comparison of anti-Vi IgG responses between two clinical studies of typhoid Vi conjugate vaccines (Vi-DT vs Vi-TT)

by Eun Young Lee, Ju Yeon Park, Deok-Ryun Kim, Manki Song, Sushant Sahastrabuddhe, Hun Kim, Yun Chon, Jae Seung YangSalmonella enterica serovar Typhi (S. Typhi) is a causative agent for typhoid fever and especially critical in developing countries. Although clinical studies for various typhoid conjugate vaccines (TCVs) have been performed, there are no comparative data on the immune responses of vaccines due to lack of harmonization of the serological assay. Recently, Typbar-TCV (Vi-TT) was prequalified by WHO and recommended for vaccination in endemic areas. Forty-eight serum samples were selected from a recent Vi-DT phase 1 study based on age cohort and anti-Vi IgG levels using an in-house ELISA. Anti-Vi IgG titers of 48 sera were also determined by Vacczyme ELISA, used in a Vi-TT phase 3 trial. A good correlation between the two assays was observed when the anti-Vi IgG titer was determined using Vacczyme ELISA based on the Vi-IgGR1,2011, U.S. reference reagent (Pearson correlation coefficient (r) = 0.991,P
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research

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This report provides an update on U.S. cases of XDR typhoid fever linked to Pakistan and describes a new, unrelated cluster of ceftriaxone-resistant Typhi infections linked to Iraq. Travelers to areas with endemic Typhi should receive typhoid vaccination before traveling and adhere to safe food and water precautions (4). Treatment of patients with typhoid fever should be guided by antimicrobial susceptibility testing whenever possible (5), and clinicians should consider travel history when selecting empiric therapy. PMID: 32437343 [PubMed - indexed for MEDLINE]
Source: MMWR Morb Mortal Wkl... - Category: Epidemiology Authors: Tags: MMWR Morb Mortal Wkly Rep Source Type: research
Reviving the "Moore swab": a classic environmental surveillance tool involving filtration of flowing surface water and sewage water to recover typhoidal Salmonella. Appl Environ Microbiol. 2020 Apr 24;: Authors: Sikorski MJ, Levine MM Abstract The Moore swab is a classic environmental surveillance tool whereby a gauze pad tied with string is suspended in flowing water or wastewater contaminated with human feces and harboring enteric pathogens that pose a human health threat. In contrast to single volume "grab" samples, Moore swabs act as continuous filters to "trap" micro...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research
We describe the epidemiology and antimicrobial susceptibility patterns of Salmonella enterica serovar Typhi (S. Typhi) infection in Laos based on isolates accrued over 18 years at Mahosot Hospital, Vientiane. All blood cultures collected from patients presenting with fever submitted to the Microbiology Laboratory at Mahosot Hospital (February 2000-December 2018) were included. This included patients from Vientiane and four provincial hospitals and one typhoid outbreak investigation. A total of 913 (1.5%) of 60,384 blood cultures were positive for S. Typhi. The majority of isolates with data available (712/898, 79.3%) were ...
Source: The American Journal of Tropical Medicine and Hygiene - Category: Tropical Medicine Authors: Tags: Am J Trop Med Hyg Source Type: research
a Saderi Andrea Piana Enteric fever is a foodborne infectious disease caused by Salmonella enterica serotypes Typhi and Paratyphi A, B and C. The high incidence in low income countries can increase the risk of disease in travelers coming from high income countries. Pre-travel health advice on hygiene and sanitation practices and vaccines can significantly reduce the risk of acquiring infections. Although the majority of the cases are self-limiting, life-threatening complications can occur. Delayed diagnosis and cases of infections caused by multi-drug resistant strains can complicate the clinical management and affec...
Source: International Journal of Environmental Research and Public Health - Category: Environmental Health Authors: Tags: Review Source Type: research
ConclusionsCollectively, the results from this randomized phase 1 clinical trial indicate that Typhax is safe, well tolerated, and immunogenic. After a single dose, Typhax at the 2.5 and 10 μg dose levels elicited comparable anti-Vi IgG titers and seroconversion rates as a single dose of Typhim Vi (25 μg dose). A second dose of Typhax at Day 28 did not elicit a booster response. Trial registrationClinicalTrials.gov NCT03926455.
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research
The burden of diarrheal diseases is very high, accounting for 1.7 to 5 billion cases per year worldwide. Typhoid Fever (TF) and Cholerare potentially life-threatening infectious diseases mainly transmitted through the consumption of food, drink or water that have been contaminated by the feces or urine of subjects excreting the pathogen. TF is mainly caused bySalmonella typhi whereas Cholera is caused by intestinal infection by the toxin-producing bacteriumVibrio cholerae.These diseases typically affect low- and middle-income countries where housing is overcrowded and water and sanitation are poor, or where conflicts or na...
Source: Journal of Preventive Medicine and Hygiene - Category: International Medicine & Public Health Source Type: research
The burden of diarrheal diseases is very high, accounting for 1.7 to 5 billion cases per year worldwide. Typhoid Fever (TF) and Cholerare potentially life-threatening infectious diseases mainly transmitted through the consumption of food, drink or water that have been contaminated by the feces or urine of subjects excreting the pathogen. TF is mainly caused by Salmonella typhi whereas Cholera is caused by intestinal infection by the toxin-producing bacterium Vibrio cholerae. These diseases typically affect low- and middle-income countries where housing is overcrowded and wa...
Source: Journal of Preventive Medicine and Hygiene - Category: International Medicine & Public Health Source Type: research
This article provides information on these and other travel vaccinations against hepatitis A, typhoid fever, rabies, Japanese encephalitis and cholera.Yellow fever endemic areas are located in Africa and in South America; there is no yellow fever in Asia. The meningococcal vaccine (A, C, W, Y) is required for pilgrims to Saudi Arabia. Additionally, it is recommended for travellers visiting the African "meningitis belt" during the dry season. A polio booster is required for countries with endemic wild-type polio virus (WPV) or circulating vaccine derived poliovirus (cVDPV).Hepatitis A is a common vaccine-prev...
Source: Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz - Category: International Medicine & Public Health Authors: Tags: Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz Source Type: research
ConclusionsThis report confirms 12 azithromycin-resistantSalmonella Typhi strains and one Paratyphi A strain. The molecular basis of this resistance is one mutation in the AcrB protein at position 717. This is the first report demonstrating the impact of this non-synonymous mutation in conferring macrolide resistance in a clinical setting. With increasing azithromycin use, strains with R717 mutations may spread and be acquired by XDR strains. An azithromycin-resistant XDR strain would shift enteric fever treatment from outpatient departments, where patients are currently treated with oral azithromycin, to inpatient departm...
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research
Abstract Enteric fever is a major public health concern in endemic areas, particularly in infrastructure-limited countries where Salmonella Paratyphi A has emerged in increasing proportion of cases. We aimed to evaluate a method to detect Salmonella Typhi (S. Typhi) and Salmonella Paratyphi A (S. Paratyphi) in febrile patients in Bangladesh. We conducted a prospective study enrolling patients with fever> 38°C admitted to two large urban hospitals and two outpatient clinics located in Dhaka, Bangladesh. We developed and evaluated a method combining short culture with a new molecular assay to simultaneously d...
Source: The American Journal of Tropical Medicine and Hygiene - Category: Tropical Medicine Authors: Tags: Am J Trop Med Hyg Source Type: research
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