1. Immunological Characteristics of a Population at Risk of Cholera Before and After 1st and 2nd Dose of Oral Cholera Vaccine (study site- Lukanga Swamps). Immunological Characteristics of a Population at Risk of Cholera Before and After 1st and 2nd Dose of Oral Cholera Vaccine (study site- Lukanga Swamps).
2. Understanding Long term immune responses following 1st and 2nd Dose of Oral Cholera Vaccination (study site- Lukanga Swamps).
3. Effect of extended dose intervals on the immune response in subjects who receive the second dose of the Oral Cholera Vaccine (Shanchol) at different intervals: 2 weeks vs 6 months following the first dose of vaccine in Zambia(study site- Lukanga Swamps).
4. Molecular characterization of Vibrio cholerae strains and implications on transmissibility between “Hotspots” in Zambia(Study site-Countrywide).

1. To determine prevalence of serological and stool markers of environmental enteric dysfunction (EED).
2. To determine the effect of EED on rotavirus vaccine seroconversion.

• Having applied the ELISA methods on paired serum samples from the ROVAS study, this project measured novel biomarkers of EED (Zonulin, Intestinal fatty acid binding protein (IFAB), soluble CD 14 (sCD14) and Endotoxin Core antibody IgG (Endocab).

• We observed high prevalence of EED: 90% (128/142) had evidence of at least one EED marker. This underscores the need for better WASH for infants and new-borns.
• Zonulin was most prevalent (82%) while sCD14 was least prevalent (8%).
• Zonulin and IFABP were positively associated with seroconversion Adjusted OR 11.3; P <0.0001 and 6.05; P<0.0001 respectively. These early markers seem to favour better vaccine uptake.
• EndoCAb and sCD14 were negatively associated with seroconversion. These late markers are deleterious to gut function and likely to have serious malabsorption consequences

Title : A Phase 1 age descending placebo controlled clinical trial to examine the safety, tolerability, and immunogenicity of an oral inactivated ETEC Vaccine (ETVAX®) with dmLT adjuvant in healthy adults and children in Zambia.

Project Summary: Diarrhoea remains one of the major causes of morbidity and death among children below five years of age living in developing counties. The majority of cases of diarrhoea which end in death occur in children below the age of two. Enterotoxigenic Escherichia coli (ETEC) is one of the top four pathogens that causes moderate to severe diarrhoea (MSD) and while strides have been made to develop vaccines for these pathogens there is currently no licensed vaccine for ETEC. ETEC is also associated with other long-term negative health and economic impacts for children (i.e. stunting, poor cognitive development) and their families in low- resource countries. Establishing the protective efficacy of promising ETEC vaccine candidates is a high priority for the World Health Organization and European & Developing Countries Clinical Trial Partnership (EDCTP).

This study seeks to evaluate a vaccine against ETEC diarrhoea called ETVAX®. The objectives are to establish the (i) safety and (ii) immunogenicity of ETVAX® in children aged 6-9 months old and 10-23 months old, respectively in Zambia. Our team aims to move ETVAX®, an inactivated whole cell vaccine candidate, into advanced clinical development including field efficacy testing. This is a Phase 1 age descending study in adults, children 10-23 months and children 6-9 months to establish the safety and immunogenicity of ETVAX® in Zambia.

In addition to the evaluation of the ETVAX vaccine this study will also support two PhD projects. The academic students on this project will contribute to closing global knowledge gaps by addressing the following objectives:

Study site:

ETVAX is being conducted in the CIDRZ Matero Clinical Research site co-located at Matero first level hospital, a government run health facility serving a peri-urban population in Lusaka Zambia.

Study title: Characterization of systemic Memory B and T cell responses to an oral inactivated vaccine against enterotoxigenic e.coli (etvax®) in Zambian children aged 6-23 months.
Study Summary: Enterotoxigenic E. coli (ETEC) is a major cause of diarrhoea in under-five children and in travelers to low- and middle-income countries (LMICs). Vaccination is widely understood to be the most effective mode of prevention of infectious diseases. Therefore, development of an ETEC vaccine is a top priority on the global health agenda. A suitable vaccine against ETEC must not only induce a mucosal IgA response but must also produce an immunological memory response. It must also induce production of cross-reactive antibodies to cover a good number of the ETEC pathotypes.
The ETVAX® vaccine (Scandinavian Biopharma, Sweden) is an inactivated oral vaccine and the most advanced of the ETEC vaccines currently under development, that has shown promising results in trials conducted in Bangladesh and Sweden.
This study will investigate the immunogenicity of ETVAX® vaccination in Zambian children (6-23 months) by examining the memory responses at various time points and correlate them with the number of doses of the vaccine. The functional capacity of vaccine-induced antibodies will also be determined.

PhD Student: Suwilanji Silwamba Study Title: Molecular Epidemiology of Enterotoxigenic Escherichia coli presented by infants under five in Lusaka.
Study Summary: Enterotoxigenic Escherichia (ETEC) is a common cause of diarrhoea in children. ETEC causes disease by adhering to the small intestine epithelium by means of colonisation factors (CFs). Effects of enterotoxins lead to watery diarrhoea symptoms. In developing countries ETEC vaccine development has become an important primary prevention strategy.
Vaccine development is driven in part by specific disease burden data. This effort will contribute to Zambian ETEC data by evaluation of stool samples from children under five affected using a novel diagnostic loop mediated isothermal amplification (LAMP) technology. Whole genome sequencing of ETEC will be used to characterize common CFs and putative virulence factors (VF) in the Lusaka population, which has never been done before and will contribute to background data needed for vaccine evaluation.
Literature suggests that AMR has increased in the last two decades and approximately 30% of clinical isolated ETEC lack a known CF. To investigate this phenomenon in Zambia, this study seeks to identify AMR patterns, novel CFs and VFs by comparative genomics as well as phenotypic analyses.

Co- Principal investigator: Nsofwa Sukwa Nsofwa Sukwa is an early career researcher who is currently working as a study physician on 2 rotavirus vaccine clinical trials. She is a medical doctor and clinical dietician currently working as a clinical research fellow under the Enteric diseases and Vaccines research unit. The unit has previously focused on two of the top five aetiological agents of childhood diarrhoea namely Rotavirus and Vibrio Cholerae and has now added Enterotoxigenic E coli (ETEC) to their portfolio through this clinical trial.

Clinical trial Registration The study is registered at Pan African Clinical Trials Registry and is available via the link: Read More

• Enrolment status: completed enrollments
• Current status: Approved by UNZABREC, participants in follow up.

Shigella is one of the most important pathogenic causes of diarrhoea disease among children under 5. It is estimated to cause as much as 164.7 million cases of diarrhoea annually of which 163.2 million cases occur in developing countries and 1.1 million cases result in death. Almost 70% of all cases occur in children under the age of 5 years. In Zambia, the EDVRU team showed that Shigella was the second leading attributable cause of moderate-to-severe diarrhoea (MSD) in children under 5. A Shigella vaccine would be a cost effective and reliable way to decrease the morbidity and mortality. However, there is currently no licensed vaccine against Shigella.

One of the greatest barriers to vaccine development is the paucity of accurate incidence data. The current complex diagnostic methods used to detect Shigella, are generally not feasible in endemic countries due to cost, none availability of reagents and a requirement for expensive and complex machinery. We propose an easy-to-use, cost-effective, and robust Polymerase Chain Reaction (PCR)-based rapid tool - the Loop-mediated isothermal amplification (LAMP) based diagnostic assay (ES-RLDT) - for the detection of Shigella and Eterotoxigenic E-coli (ETEC). This will enable us to have an accurate estimate of Shigella incidence for sample size calculation for our future clinical trial design of ShigOraVax™, a candidate vaccine to be evaluated here in Zambia.

Title :A baseline Study in Support of Clinical Evaluation of an Oral Shigella Vaccine development in Africa

• This will be a prospective cohort study of children under the age of 5. It will be characterized by a community census and the children enrolled will constitute the under 5 cohort that will be followed up to detect Shigella cases
• A passive surveillance system will be set up at the facility to detect any cases of moderate to severe diarrhea. Shigella and ETEC will be tested on the stool samples collected

The trial is registered at clinicaltrials.gov and can be accessed on clinicaltrial.gov NCT04312906

• The primary objective of the study is to determine the incidence of MSD with confirmed Shigella aetiology using the Rapid LAMP based diagnostic assay (ES_RLDT).

• To determine the incidence of MSD with confirmed Enterotoxigenic Escherichia coli (ETEC) aetiology in children under 5;
• To estimate all-cause MSD morbidity in children under 5;
• To determine the attributable fraction for Shigella among all-cause MSD in children under 5 years;
• To evaluate the predictive accuracy of the modified diarrhoea severity scoring tool among children presenting with MSD;
• To determine the spatial and temporal distribution of Shigella and ETEC in the study area in Lusaka;
• To characterize genetic diversity of Shigella causing MSD in children under 5 in Lusaka and Ndola;
• To document the antimicrobial susceptibility/resistance trends of isolates to common antibiotics;
• To explore other effects of a Shigella bout of infection on environmental enteric dysfunction and linear growth of children in Lusaka
**The trial is also contributing to research capacity strengthening through specific training of two PhD students

Study site
ShigOraVax study is being conducted at the CIDRZ Chainda South Clinical Research site located in Ibexhill. Our study population will include all children under the age of 5 residing in the catchment population for Chainda South clinic. Chainda South Health Facility provides outpatient care services primarily for populations of Kalikiliki compound, Mtendere East and parts of Ibex Hill. Another passive surveillance system for hospitalised, under 5 children with Shigella will be set up at the Arthur Davison Children’s Hospital in Ndola.

Molecular works on arboviruses circulating in selected Vector Hosts ( Mosquitoes, Wild birds and Humans) in Zambia and the Democratic Republic of Congo.

• The Jenner Institute, University of Oxford
  
• African Centre of Excellence for Infectious Diseases in Humans and Animals funding the PhD project.
  

Title : A randomised controlled trial of two versus three doses of Rotarix™ vaccine for boosting and longevity of vaccine immune responses in Zambia (ROVAS-2).
Rotavirus vaccines such as Rotarix™ are presently proven to be an effective and powerful tool for saving child lives from diarrhoea deaths in developing countries like Zambia. However, in the light of the well-known reduced immunogenicity, efficacy and effectiveness of these vaccines in developing countries compared to developed countries, there is need for further research. Based on findings from Zambia showing that Rotarix™ vaccine induced responses wane later in infancy, ROVAS-2 trial was proposed and is assessing the potential immunogenicity benefit and safety of an added third Rotarix™ dose to the regular two dose administration within the national immunisation schedule in Zambia.

• ROVAS-2 is an investigator-led, open-label randomised controlled trial comparing two versus three doses of the monovalent rotavirus vaccine, Rotarix™, in Zambian infants. The trial enrolled 212 mother-infant pairs who are prospectively followed up and from whom biological specimens are collected to profile and explore longevity of immune responses associated with vaccination, explore safety and clinical protective benefits of the added third dose, and assess the influence of maternal and infant factors on vaccine immunogenicity. The goal of the trial is to provide research evidence for a three-dose Rotarix™ vaccine schedule among Zambian infants as an alternative to the current two dose schedule to boost and provide enduring anti-rotavirus immunity.
• The trial is registered at Pan African Clinical Trials Registry and is available via the : link

Trial objectives :

• To assess boosting and longevity of rotavirus specific antibody (RV-IgA) responses between infants receiving two versus three doses of Rotarix™ vaccine.
• To assess incidence of solicited or unsolicited adverse events following third dose of Rotarix™
• To evaluate the effect of diarrhoeal disease on the growth velocity of infants
• To profile innate and rotavirus specific lymphocyte phenotypes with associated cytokine signatures and secretory IgA response for characterization of the immune responses to Rotarix™
• Profile changes in rotavirus specific antibody titres and non-immunological components in maternal breastmilk over time and determine association with infant vaccine response.
• To determine maternal and infant histo-blood group profiles and Cytomegalovirus exposure and determine association with Rotarix™ vaccine immunogenicity

The trial is also contributing to research capacity strengthening through specific training of one PhD and one MSc student

ROVAS-2 is being conducted in the CIDRZ George Clinical Research site co-located at George Clinic, a government run health facility serving a peri-urban population in Lusaka Zambia.