Arsenic--ToxicologyPAIRNCT03930017
Pregnancy, Arsenic and Immune Response
An observational study of Arsenic--Toxicology and Immunologic Disorders Complicating Pregnancy, run by Johns Hopkins Bloomberg School of Public Health at 1 site in Bangladesh.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 13 to 45 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Arsenic--Toxicology, Immunologic Disorders Complicating Pregnancy, Vaccine Response Impaired
- What is being tested?
- Seasonal influenza vaccine - VAXIGRIP TETRA influenza vaccine (quadrivalent, split virion, inactivated)
- Type of treatment
- Vaccines
- How many people
- 784 participants
- Where
- 1 siteBangladesh
- Study dates
- 14 Oct 2018to 6 Jan 2020
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 13 to 45 years
- Women only
- Healthy volunteers accepted
- Child, Adult
Study population: The study will be conducted at the Johns Hopkins JiVitA project site, in the rural Gaibandha district, Bangladesh, one of the largest project sites in South Asia, covering more than 650,000 people in an area of more than 500 sq. km. Over 150,000 married women of reproductive age have been enlisted through thirteen years of previous studies in the area with approximately 12% of registered women becoming pregnant each year.
Who may be able to join
- Women who:
- are within 13-16 weeks of gestational age (GA) of pregnancy;
- are between 13 and 45 years of age;
- are married;
- provide informed consent for herself and assent for her unborn child;
- agree to receive the seasonal influenza vaccine (VAXIGRIP® TETRA seasonal quadrivalent inactivated influenza vaccine, Sanofi Pasteur) upon study enrollment.
Who cannot join
- Women who:
- have pre-existing immune-related health condition (e.g., immunodeficiency, lupus, chronic infection, or cancer);
- previous or current use of immune-altering drug/therapy (e.g., steroids);
- have already received influenza vaccination for the current season.
Trial locations and contacts
1 site in 1 country.
Bangladesh1 site
JiVitA Maternal and Child Health and Nutrition Research Program
Gaibandha
About this study
Official title: Arsenic and Immune Response to Influenza Vaccination in Pregnant Women and Newborns
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.
Read the detailed description
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.
- Conditions
- Arsenic--Toxicology, Immunologic Disorders Complicating Pregnancy, Vaccine Response Impaired, Micronutrient Deficiency, Influenza
- Being tested
- Seasonal influenza vaccine - VAXIGRIP TETRA influenza vaccine (quadrivalent, split virion, inactivated)
- Keywords
- Observational, Influenza, Vaccine immunogenicity, Arsenic, Immunology
- Medical subject headings
- Influenza, Human
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Seasonal influenza vaccine - VAXIGRIP TETRA influenza vaccine (quadrivalent, split virion, inactivated)Biological
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.
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in influenza hemagglutination-inhibition (HI) antibody titer
Influenza hemagglutination-inhibition (HI) antibody titer will be measured in participant's serum.
Measured: 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.
Measured: Measured at baseline, 28 days post vaccination, birth, and 3 months post-partum
Seroconversion rate
The proportion of pregnant women demonstrating seroconversion
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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
Measured: Comparing baseline to 28 days post vaccination, birth, and 3 months post-partum
Secondary outcomes (4)
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.
Measured: 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.
Measured: 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.
Measured: 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).
Measured: From date of enrollment visit until date of 3 months postpartum visit, assessed at weekly intervals
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Apr 2019
- Study start14 Oct 2018
- Primary completion6 Jan 2020
- Study completion6 Jan 2020
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Arsenic--ToxicologyStudies of the same condition, open and under way.
- More trials run by Johns Hopkins Bloomberg School of Public HealthThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 784 participants (actual)
Sponsor and investigators
- Lead sponsor
- Johns Hopkins Bloomberg School of Public Health
- Sponsor type
- University, hospital or other
- Collaborators
- Sanofi Pasteur, a Sanofi Company, Institute of Epidemiology, Disease Control and Research, Johns Hopkins Bangladesh - The JiVitA Project Site, University of Graz, Columbia University, UNC Gillings School of Global Public Health
- Responsible party
- Sponsor
- Investigators
- Christopher D Heaney, PhD, Principal investigator, Johns Hopkins Bloomberg School of Public Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03930017
- Sponsor's protocol ID
- R01ES026973
- Acronym
- PAIR
- Status last verified
- Jan 2023
- First submitted
- 16 Aug 2017
- Last updated
- 5 Jan 2023
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Attreed SE, Navas-Acien A, Heaney CD. Arsenic and Immune Response to Infection During Pregnancy and Early Life. Curr Environ Health Rep. 2017 Jun;4(2):229-243. doi: 10.1007/s40572-017-0141-4.
PubMed 28488132Heaney CD, Kmush B, Navas-Acien A, Francesconi K, Gossler W, Schulze K, Fairweather D, Mehra S, Nelson KE, Klein SL, Li W, Ali H, Shaikh S, Merrill RD, Wu L, West KP Jr, Christian P, Labrique AB. Arsenic exposure and hepatitis E virus infection during pregnancy. Environ Res. 2015 Oct;142:273-80. doi: 10.1016/j.envres.2015.07.004. Epub 2015 Jul 15.
PubMed 26186135Avolio LN, Smith TJS, Navas-Acien A, Kruczynski K, Pisanic N, Randad PR, Detrick B, Fry RC, van Geen A, Goessler W, Karron RA, Klein SL, Ogburn EL, Wills-Karp M, Alland K, Ayesha K, Dyer B, Islam MT, Oguntade HA, Rahman MH, Ali H, Haque R, Shaikh S, Schulze KJ, Muraduzzaman AKM, Alamgir ASM, Flora MS, West KP Jr, Labrique AB, Heaney CD; JiVitA Maternal and Child Health and Nutrition Research Project. The Pregnancy, Arsenic, and Immune Response (PAIR) Study in rural northern Bangladesh. Paediatr Perinat Epidemiol. 2023 Feb;37(2):165-178. doi: 10.1111/ppe.12949. Epub 2023 Feb 9.
PubMed 36756808
Study at a glance
From the registry record, last updated by the sponsor on 5 Jan 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Arsenic and Immune Response to Influenza Vaccination in Pregnant Women and Newborns
- ClinicalTrials.gov ID
- NCT03930017
- Acronym / sponsor ID
- PAIR / R01ES026973
- Conditions
- Arsenic--Toxicology, Immunologic Disorders Complicating Pregnancy, Vaccine Response Impaired, Micronutrient Deficiency, Influenza
- Keywords
- Observational, Influenza, Vaccine immunogenicity, Arsenic, Immunology
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 784 participants (actual)
- Lead sponsor
- Johns Hopkins Bloomberg School of Public HealthUniversity, hospital or other
- Collaborators
- Sanofi Pasteur, a Sanofi Company, Institute of Epidemiology, Disease Control and Research, Johns Hopkins Bangladesh - The JiVitA Project Site, University of Graz, Columbia University, UNC Gillings School of Global Public Health
- Study start
- 14 Oct 2018 (actual)
- Primary completion
- 6 Jan 2020 (actual)
- Study completion
- 6 Jan 2020 (actual)
- First posted
- 29 Apr 2019 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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 design
- Observational model
- Cohort
- Time perspective
- Prospective
Who may qualify
- Ages
- 13 to 45 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
- Study population
- The study will be conducted at the Johns Hopkins JiVitA project site, in the rural Gaibandha district, Bangladesh, one of the largest project sites in South Asia, covering more than 650,000 people in an area of more than 500 sq. km. Over 150,000 married women of reproductive age have been enlisted through thirteen years of previous studies in the area with approximately 12% of registered women becoming pregnant each year.
Key inclusion criteria (6 listed)
- are within 13-16 weeks of gestational age (GA) of pregnancy;
- are between 13 and 45 years of age;
- are married;
- provide informed consent for herself and assent for her unborn child;
- agree to receive the seasonal influenza vaccine (VAXIGRIP® TETRA seasonal quadrivalent inactivated influenza vaccine, Sanofi Pasteur) upon study enrollment.
Key exclusion criteria (4 listed)
- have pre-existing immune-related health condition (e.g., immunodeficiency, lupus, chronic infection, or cancer);
- previous or current use of immune-altering drug/therapy (e.g., steroids);
- have already received influenza vaccination for the current season.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Seasonal influenza vaccine - VAXIGRIP TETRA influenza vaccine (quadrivalent, split virion, inactivated)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. | Biological | – |
Primary outcome
Change in influenza hemagglutination-inhibition (HI) antibody titer
Time frame: Comparing baseline to 28 days post vaccination, birth, and 3 months post-partum
Influenza hemagglutination-inhibition (HI) antibody titer will be measured in participant's serum.
Mean percent influenza virus antibody avidity
Time frame: Measured at baseline, 28 days post vaccination, birth, and 3 months post-partum
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.
Seroconversion rate
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.
The proportion of pregnant women demonstrating seroconversion
Change in geometric mean HI antibody titer (GMT)
Time frame: Comparing baseline to 28 days post vaccination, birth, and 3 months post-partum
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.
Geometric mean ratio of infant:mother HI titer
Time frame: Birth and 3 months post-partum
Ratio of infant to mother HI titer as a measure of transplacental transfer of influenza antibody.
Change in influenza virus neutralizing antibody titer
Time frame: Comparing baseline to 28 days post vaccination, birth, and 3 months post-partum
Virus neutralization is measured as a titer calculated based on the highest serum dilution that eliminates virus.
Change in anti-influenza virus total immunoglobulin G (IgG) enzyme immunoassay
Time frame: Comparing baseline to 28 days post vaccination, birth, and 3 months post-partum
Total IgG antibodies to influenza virus as measured in serum or plasma by enzyme immunoassay
4 secondary outcomes
Maternal influenza-like illness (ILI)
Time frame: From date of enrollment visit until date of 3 months postpartum visit, assessed at weekly intervals
Infant influenza-like illness (ILI)
Time frame: From date of birth visit until date of 3 months postpartum visit, assessed at weekly intervals
Laboratory-confirmed influenza (LCI)
Time frame: From date of enrollment visit until date of 3 months postpartum visit, assessed at weekly intervals
Acute respiratory illness (ARI)
Time frame: From date of enrollment visit until date of 3 months postpartum visit, assessed at weekly intervals
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Jan 2023.
- Background: PubMed 28488132Attreed SE, Navas-Acien A, Heaney CD. Arsenic and Immune Response to Infection During Pregnancy and Early Life. Curr Environ Health Rep. 2017 Jun;4(2):229-243. doi: 10.1007/s40572-017-0141-4.
- Background: PubMed 26186135Heaney CD, Kmush B, Navas-Acien A, Francesconi K, Gossler W, Schulze K, Fairweather D, Mehra S, Nelson KE, Klein SL, Li W, Ali H, Shaikh S, Merrill RD, Wu L, West KP Jr, Christian P, Labrique AB. Arsenic exposure and hepatitis E virus infection during pregnancy. Environ Res. 2015 Oct;142:273-80. doi: 10.1016/j.envres.2015.07.004. Epub 2015 Jul 15.
- Derived from this study: PubMed 36756808Avolio LN, Smith TJS, Navas-Acien A, Kruczynski K, Pisanic N, Randad PR, Detrick B, Fry RC, van Geen A, Goessler W, Karron RA, Klein SL, Ogburn EL, Wills-Karp M, Alland K, Ayesha K, Dyer B, Islam MT, Oguntade HA, Rahman MH, Ali H, Haque R, Shaikh S, Schulze KJ, Muraduzzaman AKM, Alamgir ASM, Flora MS, West KP Jr, Labrique AB, Heaney CD; JiVitA Maternal and Child Health and Nutrition Research Project. The Pregnancy, Arsenic, and Immune Response (PAIR) Study in rural northern Bangladesh. Paediatr Perinat Epidemiol. 2023 Feb;37(2):165-178. doi: 10.1111/ppe.12949. Epub 2023 Feb 9.
- JiVitA Maternal and Child Health and Nutrition Research Project Site in BangladeshLink provided by the sponsor.
- Institute of Epidemiology and Disease Control Research (IEDCR) collaboratorLink provided by the sponsor.
- Johns Hopkins University (JHU) Center for Human NutritionLink provided by the sponsor.
- Johns Hopkins Environmental Health Microbiology and Immunology LaboratoryLink provided by the sponsor.
- Individual participant dataSharing planned: No
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Christopher D Heaney, PhD principal investigator
Johns Hopkins Bloomberg School of Public Health
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Arsenic--Toxicology and Immunologic Disorders Complicating Pregnancy, run by Johns Hopkins Bloomberg School of Public Health at 1 site in Bangladesh.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 5 Jan 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Bangladesh. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in influenza hemagglutination-inhibition (HI) antibody titer (time frame: Comparing baseline to 28 days post vaccination, birth, and 3 months post-partum). The study lists 7 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03930017, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Jan 2023.