As the global availability of vaccines increases, and reaches areas disproportionately affected by arsenic and malnutrition, resolving questions about potential environmental and biologic barriers to maternal immunization has become increasingly urgent. It is not known whether arsenic, a known developmental toxicant, can alter maternal immune responses to vaccination and whether exposure to arsenic during pregnancy can impair the transfer of maternal vaccine-induced antibody to the newborn. Moreover, factors known to affect arsenic metabolism and toxicity outcomes, particularly micronutrients critical in one-carbon metabolism, have not been evaluated in studies of arsenic immunotoxicity and vaccine-induced protection in mothers and their newborns. The objective in this study is to investigate whether maternal arsenic exposure and one-carbon metabolism micronutrient deficiencies alter maternal and newborn measures of vaccine-induced protection, respiratory morbidity, and systemic immune function following influenza vaccination during pregnancy.
The objective in this study is to investigate whether maternal arsenic exposure and one-carbon metabolism micronutrient deficiencies alter maternal and newborn measures of vaccine-induced protection, respiratory morbidity, and systemic immune function following influenza vaccination during pregnancy. The hypothesis is that maternal arsenic exposure and one-carbon metabolism micronutrient deficiencies alter maternal and newborn influenza antibody titer and avidity, respiratory infection morbidity, and markers of systemic immune function following maternal influenza vaccination during pregnancy. This study leverages a comprehensive pregnancy surveillance system at the JiVitA Maternal and Child Health and Nutrition Research Project site in Bangladesh (hereafter JiVitA) to pursue the following three aims: Aim 1. Establish whether arsenic exposure during pregnancy alters maternal and newborn influenza antibody titer and avidity following maternal influenza vaccination. Aim 2. Determine whether markers of systemic immune function mediate the association between arsenic exposure and respiratory illness in pregnant women and their newborns. Aim 3. Assess whether arsenic exposure and one-carbon metabolism micronutrient deficiencies during pregnancy have a joint effect on markers of systemic immune function and respiratory illness in mothers and their newborns. This study will yield three expected outcomes. First, it will fill critical knowledge gaps about whether arsenic exposure and one-carbon metabolism micronutrient deficiencies alter immune responses to a vaccination with known benefits for mothers and their newborns. Second, it will increase understanding of arsenic-associated respiratory morbidity and specific immune function pathways between arsenic exposure and respiratory morbidity in mothers and their newborns. Finally, as the global availability of vaccines increases, improving knowledge of potential environmental and biologic barriers to maternal and newborn vaccine-induced protection could lead to improved vaccine regimens (targeted vaccination campaigns, higher vaccine doses, and/or additional booster immunizations) to restore vaccine-induced protection in arsenic-exposed and malnutrition-affected populations of pregnant women and newborns worldwide.
Study Type
OBSERVATIONAL
Enrollment
784
Influenza virus (quadrivalent, split virion, inactivated) of the strains that comply with the World Health Organization (WHO) recommendations (Northern Hemisphere) and European Union (EU) decision for the 2018/2019 season. The quadrivalent vaccine is propagated in fertilised hens' eggs from healthy chicken flocks.
JiVitA Maternal and Child Health and Nutrition Research Program
Gaibandha, Bangladesh
Change in influenza hemagglutination-inhibition (HI) antibody titer
Influenza hemagglutination-inhibition (HI) antibody titer will be measured in participant's serum.
Time frame: Comparing baseline to 28 days post vaccination, birth, and 3 months post-partum
Mean percent influenza virus antibody avidity
The accumulated strength of multiple affinities of individual non-covalent binding interactions of influenza-specific antibodies, including avidity of antibodies to seasonal inactivated influenza virus (IIV) strains included in the formulation in Sanofi Pasteur's 2018-2019 seasonal VAXIGRIP® TETRA vaccine.
Time frame: Measured at baseline, 28 days post vaccination, birth, and 3 months post-partum
Seroconversion rate
The proportion of pregnant women demonstrating seroconversion
Time frame: Defined as a post-vaccination HI titer of ≥40 given a pre-vaccination titer ≤10 or, alternatively, a ≥4-fold increase in HI titer between pre-vaccination and post-vaccination sera if the pre-vaccination titer was >10.
Change in geometric mean HI antibody titer (GMT)
GMT HI antibody titers will be transformed to binary logarithms, and original values will be divided by 4 (undetectable titer) to set the starting point of the log scale to zero prior to transformation. We will calculate average log2 GMT antibody titers.
Time frame: Comparing baseline to 28 days post vaccination, birth, and 3 months post-partum
Geometric mean ratio of infant:mother HI titer
Ratio of infant to mother HI titer as a measure of transplacental transfer of influenza antibody.
Time frame: Birth and 3 months post-partum
Change in influenza virus neutralizing antibody titer
Virus neutralization is measured as a titer calculated based on the highest serum dilution that eliminates virus.
Time frame: Comparing baseline to 28 days post vaccination, birth, and 3 months post-partum
Change in anti-influenza virus total immunoglobulin G (IgG) enzyme immunoassay
Total IgG antibodies to influenza virus as measured in serum or plasma by enzyme immunoassay
Time frame: Comparing baseline to 28 days post vaccination, birth, and 3 months post-partum
Maternal influenza-like illness (ILI)
Defined as at least one symptom-free day prior to onset of fever \>37.8°C and cough or sore throat.
Time frame: From date of enrollment visit until date of 3 months postpartum visit, assessed at weekly intervals
Infant influenza-like illness (ILI)
Defined as at least one symptom-free day prior to onset of fever \>37.8°C and cough.
Time frame: From date of birth visit until date of 3 months postpartum visit, assessed at weekly intervals
Laboratory-confirmed influenza (LCI)
Influenza A and/or B virus real-time (RT)-quantitative polymerase chain reaction (qPCR) positive nasal swab from a participant reporting ILI at a weekly mobile phone positive follow-up.
Time frame: From date of enrollment visit until date of 3 months postpartum visit, assessed at weekly intervals
Acute respiratory illness (ARI)
Defined as: cough; rapid breathing or grunting or wheezing, excluding asthma; blood in sputum; ear discharge; low fever; and/or headache. A stand-alone outcome of ARI plus fever will be defined as the above symptoms plus high fever \>37.8°celsius (C).
Time frame: From date of enrollment visit until date of 3 months postpartum visit, assessed at weekly intervals
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