Protection by vaccination of children against typhoid fever with a Vi-tetanus toxoid conjugate vaccine in urban Bangladesh: a cluster-randomised trial

BACKGROUND

Typhoid fever remains a major cause of morbidity and mortality in low-income and middle-income countries. Vi-tetanus toxoid conjugate vaccine (Vi-TT) is recommended by WHO for implementation in high-burden countries, but there is little evidence about its ability to protect against clinical typhoid in such settings.

METHODS

We did a participant-masked and observer-masked cluster-randomised trial preceded by a safety pilot phase in an urban endemic setting in Dhaka, Bangladesh. 150 clusters, each with approximately 1350 residents, were randomly assigned (1:1) to either Vi-TT or SA 14-14-2 Japanese encephalitis (JE) vaccine. Children aged 9 months to less than 16 years were invited via parent or guardian to receive a single, parenteral dose of vaccine according to their cluster of residence. The study population was followed for an average of 17·1 months. Total and overall protection by Vi-TT against blood culture-confirmed typhoid were the primary endpoints assessed in the intention-to-treat population of vaccinees or all residents in the clusters. A subset of approximately 4800 participants was assessed with active surveillance for adverse events. The trial is registered at www.isrctn.com, ISRCTN11643110.

FINDINGS

41 344 children were vaccinated in April-May, 2018, with another 20 412 children vaccinated at catch-up vaccination campaigns between September and December, 2018, and April and May, 2019. The incidence of typhoid fever (cases per 100 000 person-years) was 635 in JE vaccinees and 96 in Vi-TT vaccinees (total Vi-TT protection 85%; 97·5% CI 76 to 91, p<0·0001). Total vaccine protection was consistent in different age groups, including children vaccinated at ages under 2 years (81%; 95% CI 39 to 94, p=0·0052). The incidence was 213 among all residents in the JE clusters and 93 in the Vi-TT clusters (overall Vi-TT protection 57%; 97·5% CI 43 to 68, p<0·0001). We did not observe significant indirect vaccine protection by Vi-TT (19%; 95% CI -12 to 41, p=0·20). The vaccines were well tolerated, and no serious adverse events judged to be vaccine-related were observed.

INTERPRETATION

Vi-TT provided protection against typhoid fever to children vaccinated between 9 months and less than 16 years. Longer-term follow-up will be needed to assess the duration of protection and the need for booster doses.

FUNDING

The study was funded by the Bill & Melinda Gates Foundation.

Diarrhea Case Surveillance in the Enterics for Global Health Shigella Surveillance Study: Epidemiologic Methods

Background

Shigella is a leading cause of acute watery diarrhea, dysentery, and diarrhea-attributed linear growth faltering, a precursor to stunting and lifelong morbidity. Several promising Shigella vaccines are in development and field efficacy trials will require a consortium of potential vaccine trial sites with up-to-date Shigella diarrhea incidence data.

Methods

The Enterics for Global Health (EFGH) Shigella surveillance study will employ facility-based enrollment of diarrhea cases aged 6-35 months with 3 months of follow-up to establish incidence rates and document clinical, anthropometric, and financial consequences of Shigella diarrhea at 7 country sites (Mali, Kenya, The Gambia, Malawi, Bangladesh, Pakistan, and Peru). Over a 24-month period between 2022 and 2024, the EFGH study aims to enroll 9800 children (1400 per country site) between 6 and 35 months of age who present to local health facilities with diarrhea. Shigella species (spp.) will be identified and serotyped from rectal swabs by conventional microbiologic methods and quantitative polymerase chain reaction. Shigella spp. isolates will undergo serotyping and antimicrobial susceptibility testing. Incorporating population and healthcare utilization estimates from contemporaneous household sampling in the catchment areas of enrollment facilities, we will estimate Shigella diarrhea incidence rates.

Conclusions

This multicountry surveillance network will provide key incidence data needed to design Shigella vaccine trials and strengthen readiness for potential trial implementation. Data collected in EFGH will inform policy makers about the relative importance of this vaccine-preventable disease, accelerating the time to vaccine availability and uptake among children in high-burden settings.

Effect of different staking methods and stem pruning on yield and quality of summer tomato

The study was carried out during summer of 2012 with BARI hybrid tomato 4, planted in the Olericulture farm of Bangladesh Agriculture Research Institute, Joydebpur, Gazipur, Bangladesh to find out the response of plants to some staking and pruning treatments on yield, fruit quality and cost of production. A two factor experiment consisting of three staking methods and four level of pruning, laid out in complete block design with three repetitions. Plants were staked on inverted „V? shaped staking, high platform and string. The plants were pruned to two stem, three stem, four stem and no pruning as control. Results showed that significantly the highest total number of fruits per plant (37.1), marketable fruits per plant (33.7), yield per plant (1.68 kg) and total yield (44.6 t/ha) were produced by the plants having the treatment string staking with four stem. The highest fruit set (43.50%) was found in the plants staking with string having three stems. Plants grown on string staking allowing two stem gave the maximum length (4.71 cm), diameter (4.83 cm) and weight (53.4g) of single fruit as well as maximum fruit firmness (3.43 kg-f cm-2). From the economic point of view, it was apparent that summer tomato produced by string staking with four stem pruning exhibited better performance compared to other treatment combinations in relation to net return and BCR (2.10).Bangladesh J. Agril. Res. 41(3): 419-432, September 2016

Immune responses in children after vaccination with a typhoid Vi-tetanus toxoid conjugate vaccine in Bangladesh

A cluster-randomized trial of Vi-TT was conducted in Dhaka, Bangladesh, using JE vaccine as the control. A subset of 1,500 children were randomly selected on 2:1 basis (Vi-TT vs JE) to assess immune response. Blood was collected before vaccination, and on days 28, 545 and 730 post-vaccination and plasma anti-Vi-IgG response was measured. A robust, persistent antibody response was induced after single dose of Vi-TT, even after 2 years of vaccination. While there is no accepted serological antibody threshold of protection, analyzing the antibodies of children who received Vi-TT provides evidence that may later be useful in predicting population protection.

Molecular simulation studies to reveal the binding mechanisms of shikonin derivatives inhibiting VEGFR-2 kinase

Traditional vascular endothelial growth factor receptor 2 (VEGFR-2) inhibitors can manage angiogenesis; however, severe toxicity and resistance limit their long-term applications in clinical therapy. Shikonin (SHK) and its derivatives could be promising to inhibit the VEGFR-2 mediated angiogenesis, as they are reported to bind in the catalytic kinase domain with low affinity. However, the detailed molecular insights and binding dynamics of these natural inhibitors are unknown, which is crucial for potential SHK based lead design. Therefore, the present study employed molecular modeling and simulations techniques to get insight into the binding behaviors of SHK and its two derivates, β-hydroxyisovalerylshikonin (β-HIVS) and acetylshikonin (ACS). Here the intermolecular interactions between protein and ligands were studied by induced fit docking approach, which were further evaluated by treating QM/MM (quantum mechanics/molecular mechanics) and molecular dynamics (MD) simulation. The result showed that the naphthazarin ring of the SHK derivates is vital for strong binding to the catalytic domain; however, the binding stability can be modulated by the side chain modification. Because of having electrostatic potential, this ring makes essential interactions with the DFG (Asp1046 and Phe1047) motif and also allows interacting with the allosteric binding site. Taken together, the studies will advance our knowledge and scope for the development of new selective VEGFR-2 inhibitors based on SHK and its analogs.

Data Management in Multicountry Consortium Studies: The Enterics For Global Health (EFGH) Shigella Surveillance Study Example

Background

Rigorous data management systems and planning are essential to successful research projects, especially for large, multicountry consortium studies involving partnerships across multiple institutions. Here we describe the development and implementation of data management systems and procedures for the Enterics For Global Health (EFGH) Shigella surveillance study-a 7-country diarrhea surveillance study that will conduct facility-based surveillance concurrent with population-based enumeration and a health care utilization survey to estimate the incidence of Shigella--associated diarrhea in children 6 to 35 months old.

Methods

The goals of EFGH data management are to utilize the knowledge and experience of consortium members to collect high-quality data and ensure equity in access and decision-making. During the planning phase before study initiation, a working group of representatives from each EFGH country site, the coordination team, and other partners met regularly to develop the data management systems for the study.

Results

This resulted in the Data Management Plan, which included selecting REDCap and SurveyCTO as the primary database systems. Consequently, we laid out procedures for data processing and storage, study monitoring and reporting, data quality control and assurance activities, and data access. The data management system and associated real-time visualizations allow for rapid data cleaning activities and progress monitoring and will enable quicker time to analysis.

Conclusions

Experiences from this study will contribute toward enriching the sparse landscape of data management methods publications and serve as a case study for future studies seeking to collect and manage data consistently and rigorously while maintaining equitable access to and control of data.

The Enterics for Global Health (EFGH) Shigella Surveillance Study in Bangladesh

Background

Shigella is an important cause of diarrhea in Bangladeshi children <5 years of age, with an incidence rate of 4.6 per 100 person-years. However, the report was more than a decade old, and data on Shigella consequences are similarly outdated and heterogeneously collected.

Methods

Facility-based disease surveillance is planned to be carried out under the Enterics for Global Health (EFGH) Shigella Surveillance Study consortium for 2 years with aims to optimize and standardize laboratory techniques and healthcare utilization and coverage survey, clinical and anthropometric data collection, safety monitoring and responsiveness, and other related activities. The EFGH is a cohesive network of multidisciplinary experts, capable of operating in concert to conduct the study to generate data that will pave the way for potential Shigella vaccine trials in settings with high disease burden. The study will be conducted within 7 country sites in Asia, Africa, and Latin America.

Conclusions

We outline the features of the Bangladesh site as part of this multisite surveillance network to determine an updated incidence rate and document the consequences of Shigella diarrhea in children aged 6-35 months, which will help inform policymakers and to implement the future vaccine trials.

Recurrent Laryngeal Nerve Injury in Thyroid Surgery: One Year Prospective Study in a Tertiary Care Hospital

This prospective, cross sectional study was carried out in the Department of Otolaryngology & Head-Neck Surgery, Mymensingh Medical College Hospital, Bangladesh from August 2010 to July 2011. One hundred & twenty eight (128) patients with thyroid swelling who underwent surgery were purposely included. The study was designed to determine the incidence of recurrent laryngeal nerve injury during thyroid surgery. Among the 128 patients, female were predominant 78.90%, majority of the patient were in third decade, 96.87% patients were biochemically euthyroid. Total 5.46% patient had recurrent laryngeal nerve injury. Among them 14.28% had transient and 85.72% had permanent injury. Injury was more in total thyroidectomy done for extensive malignancy.

A Comparative Study between Double Knot and Single Knot Tension Band Wire Techniques in Mayo Type IIA Olecranon Fracture

Olecranon fracture, common in upper extremity trauma, occurs due to a direct impact to the point of the elbow or a fall onto an outstretched hand. Being an intra-articular fracture, treatment is aimed to anatomic reduction, stable fixation and early mobilization. Tension band wiring (TBW) is a popular and widely practiced method using either single or double knot technique. But in our country single knot technique is commonly practiced. Aim of this study was to compare the clinical, radiological and functional outcome between double knot and single knot TBW techniques in Mayo type IIA olecranon fracture. This prospective observational study was conducted at NITOR, Dhaka, Bangladesh from January 2018 to December 2019. Patients with Mayo type IIA olecranon fractures were enrolled. Total 54 cases were included. Among them, 29 cases were treated with single knot (SK group) and 25 were treated with double knot (DK group). Both groups were compared by clinical and radiological outcome. Persistent mild pain and symptomatic hardware was significantly more among the SK group (p value 0.045 for both). No other significant inter group differences were found on overall incidence of complications (p value 0.0825), the arc of motion and MEPS. The final outcome of 49 cases, 25(51.02%) were excellent and remaining 24(48.98%) were good. Both procedures were safe in regard to overall complication rate. Double knot group had significantly more excellent results then single knot group (p value 0.022). It was concluded that, double knot TBW technique provides better outcome than single knot technique.

Evaluation of oral cholera vaccine (Euvichol-Plus) effectiveness against Vibrio cholerae in Bangladesh: an interim analysis

INTRODUCTION

Millions of Euvichol-Plus doses have been deployed from the global oral cholera vaccine stockpile in over 20 cholera-affected countries. However, information on Euvichol-Plus's effectiveness is limited. Using this vaccine in a cholera epidemic in Dhaka, Bangladesh, provided the opportunity to evaluate the vaccine effectiveness (VE) using a test-negative design.

METHODS

A two-dose regimen of Euvichol-Plus was administered to individuals aged >1 year in a population of ca. 900 000 in two campaign rounds between June and August 2022, with prospective registration of all persons who received at least one dose. We conducted systematic surveillance in two key facilities, enrolling patients with acute watery diarrhoea who were eligible for vaccination from the campaign's start and who presented for care between 21 August 2022 and 20 August 2023. Faecal culture-positive cholera cases were matched to up to four faecal culture-negative controls by age, presentation date and facility. Vaccination status was documented without knowledge of culture results. Conditional logistic regression models estimated the OR for the vaccination-cholera association, and the VE of the two-dose regimen was calculated as [(1-OR) × 100].

RESULTS

The analysis included 226 cases and 552 matched controls. The adjusted VE of two doses of the Euvichol-Plus vaccine against medically attended cholera was 66% (99.5% CI: 30 to 83) for all recipients. Limited protection (12%; 95% CI: -95 to 60) was observed for children aged 1-4 years; whereas, protection was 79% (95% CI: 60 to 89) for those aged ≥5 years. VE against cholera with moderate to severe dehydration was 69% (95% CI: 44 to 83) overall but 6% (95% CI: -206 to 71) for children aged 1-4 years.

CONCLUSION

Euvichol-Plus provided significant protection against medically attended cholera of any severity as well as cholera with moderate to severe dehydration. However, significant levels of protection were only observed for those aged ≥5 years.