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

Summary

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.

Conditions

• Iron Deficiency Anemia

Interventions

OTHER

Iron-fortified cookies

Study cookies fortified with ferrous fumarate, providing 15 mg of elemental iron in each portion.

BIOLOGICAL

Japanese encephalitis (JE) vaccine

All participants will be administered the live attenuated JE vaccine

BIOLOGICAL

Typhoid Vi polysaccharide (Vi-PS) vaccine

All participants will be administered the typhoid Vi-PS vaccine

OTHER

non-fortified cookies

Study cookies containing no iron

Sponsors & Collaborators

• Mahidol University

  collaborator OTHER

• Ministry of Health, Thailand

  collaborator OTHER_GOV

• University of Oxford

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

49 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2023-09-06

Primary Completion

2024-09-30

Completion

2024-12-30

Countries

• Thailand

Study Locations