Iron Fortified Food to Improve Japanese Encephalitis and Typhoid Fever Vaccine Immunogenicity

Study Overview
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Brief Summary
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Iron deficiency (ID) anaemia (IDA) is a global public health problem, with the highest prevalence in Africa and in South-East Asia. While immunization programs have achieved high global coverage, vaccines often underperform in low- and middle-income countries (LMIC). The cause remains uncertain, but undernutrition, including ID, likely plays a role. Our recent in vitro and in vivo studies have shown the importance of iron status in adaptive immunity and vaccine response. Hypoferremia blunted T cell, B cell, and neutralizing antibody responses to influenza virus infection in mice, allowing the virus to persist. Iron deficient anaemic Kenyan women receiving intravenous iron at time of vaccination had a better immune response to the first dose of the ChAdOx Coronavirus 19 (COVID-19) vaccine and yellow fever vaccine. Japanese encephalitis and typhoid fever are endemic in Thailand. Vaccines are available but show variable efficacy. Whether ID impairs adult vaccine response to the live attenuated Japanese encephalitis (JE) and the Typhoid Vi polysaccharide (Vi-PS) vaccine and whether iron repletion via iron fortification improves vaccine response is uncertain. The objective of this study is to assess whether IDA in Thai women impairs immune response to the JE and the Typhoid Vi-PS vaccine and whether fortification iron improves their response. In this double-blind randomized controlled trial, IDA women will be assigned to two study groups: group 1 (fortification group) will receive iron-fortified biscuits (15mg iron as ferrous fumarate) for 56 days; group 2 (control group) will receive non-fortified biscuits for 56 days. All women will receive live attenuated JE and Typhoid Vi-PS vaccine on study day 28. Vaccine response will be measured 28 days after vaccination (on day 56) in both groups.

Official Title
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Iron Fortified Food to Improve Japanese Encephalitis and Typhoid Fever Vaccine Immunogenicity: a Randomized Controlled Trial in Iron Deficient Thai Women

Conditions
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Iron Deficiency Anemia

Intervention / Treatment
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* Other: Iron-fortified cookies
* Biological: Japanese encephalitis (JE) vaccine
* Biological: Typhoid Vi polysaccharide (Vi-PS) vaccine
* Other: non-fortified cookies


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participant is willing and able to give informed consent for participation in the trial. Female aged 18-49 years. Diagnosed with anaemia (i.e. hemoglobin (Hb) concentration <12 g/dl), but no severe anaemia (Hb <8 g/dl), and iron deficiency (ZnPP >40 µmol/mol) Anticipated residence in the area for the study duration Exclusion Criteria: Pregnant (confirmed by rapid test during screening and at time of vaccination), lactating or planning pregnancy during the trial. Blood transfusion or intravenous iron treatment within 4 months of study start Major chronic infectious disease (e.g., tuberculosis, HIV+, hepatitis) Major chronic non-infectious disease (e.g., Type 1 or 2 diabetes, cancer) Treatment with supplemental iron two weeks prior to enrolment JE or typhoid vaccine within the past two years

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 49 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Iron fortification group<br>Participants assigned to this group will receive iron-fortified cookies daily for the whole study duration | Other: Iron-fortified cookies<br>* Study cookies fortified with ferrous fumarate, providing 15 mg of elemental iron in each portion.<br>Biological: Japanese encephalitis (JE) vaccine<br>* All participants will be administered the live attenuated JE vaccine<br>Biological: Typhoid Vi polysaccharide (Vi-PS) vaccine<br>* All participants will be administered the typhoid Vi-PS vaccine<br>|
| Placebo Comparator: Control group<br>Participants assigned to this group will receive the same cookies containing no iron daily for the whole study duration | Biological: Japanese encephalitis (JE) vaccine<br>* All participants will be administered the live attenuated JE vaccine<br>Biological: Typhoid Vi polysaccharide (Vi-PS) vaccine<br>* All participants will be administered the typhoid Vi-PS vaccine<br>Other: non-fortified cookies<br>* Study cookies containing no iron<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Immunoglobulin G (IgG) concentrations against Salmonella Typhi |  | day 28 (time of vaccination) | 
| Immunoglobulin A (IgA) concentrations against Salmonella Typhi |  | day 28 (time of vaccination) | 
| Immunoglobulin G (IgG) concentrations against Salmonella Typhi |  | day 56 (4 weeks after vaccination) | 
| Immunoglobulin A (IgA) concentrations against Salmonella Typhi |  | day 56 (4 weeks after vaccination) | 
| Neutralizing antibodies against Japanese encephalitis |  | day 28 (time of vaccination) | 
| Neutralizing antibodies against Japanese encephalitis |  | day 56 (4 weeks after vaccination) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hemoglobin concentration (g/dL) |  | day 0 | 
| Hemoglobin concentration (g/dL) |  | day 28 | 
| Hemoglobin concentration (g/dL) |  | day 56 | 
| zinc protoporphyrin (ZnPP) concentration (µmol/mol heme) |  | day 0 | 
| zinc protoporphyrin (ZnPP) concentration (µmol/mol heme) |  | day 28 | 
| zinc protoporphyrin (ZnPP) concentration (µmol/mol heme) |  | day 56 | 
| serum iron (SFe) concentration (ng/µl) |  | day 0 | 
| serum iron (SFe) concentration (ng/µl) |  | day 28 | 
| serum iron (SFe) concentration (ng/µl) |  | day 56 | 
| total iron binding capacity (µg/dL) |  | day 0 | 
| total iron binding capacity (µg/dL) |  | day 28 | 
| total iron binding capacity (µg/dL) |  | day 56 | 
| transferrin saturation (TSAT) (%) |  | day 0 | 
| transferrin saturation (TSAT) (%) |  | day 28 | 
| transferrin saturation (TSAT) (%) |  | day 56 | 
| plasma ferritin (PF) concentration (µg/L) |  | day 0 | 
| plasma ferritin (PF) concentration (µg/L) |  | day 28 | 
| plasma ferritin (PF) concentration (µg/L) |  | day 56 | 
| soluble transferrin receptor (sTfR) concentration (mg/L) |  | day 0 | 
| soluble transferrin receptor (sTfR) concentration (mg/L) |  | day 28 | 
| soluble transferrin receptor (sTfR) concentration (mg/L) |  | day 56 | 
| C-reactive protein (CRP) concentration (mg/L) |  | day 0 | 
| C-reactive protein (CRP) concentration (mg/L) |  | day 28 | 
| C-reactive protein (CRP) concentration (mg/L) |  | day 56 | 
| alpha-glycoprotein (AGP) concentration (g/L) |  | day 0 | 
| alpha-glycoprotein (AGP) concentration (g/L) |  | day 28 | 
| alpha-glycoprotein (AGP) concentration (g/L) |  | day 56 | 
| retinol-binding protein concentration (µmol/L) |  | day 0 | 
| retinol-binding protein concentration (µmol/L) |  | day 28 | 
| retinol-binding protein concentration (µmol/L) |  | day 56 |