Maternal Determinants of Immunity to Influenza

Phase 4

Completed

• Conditions: Maternal-Fetal Relations; Influenza; Immunoglobulins; Vaccination; Infection
• Interventions: Biological: Influenza vaccine

• Registration Number: NCT06716567
• Lead Sponsor: Centre Hospitalier Universitaire Saint Pierre

Brief Summary

The overall objective of the project is to determine the impact of pregnancy on the response to influenza immunization.

Detailed Description

The study compares immune responses to influenza vaccination between a group of pregnant women and a group of non-pregnant controls women. Specifically, the study has three aims:

1. To compare the quality of antibodies induced by influenza immunization in pregnant and non-pregnant women;

2. To identify immune predictors of vaccine responses in pregnant women and compare them to the determinants of vaccine responses in non-pregnant women;

3. To identify immune predictors of the transfer of maternal antibodies to the newborn following influenza immunization during pregnancy;

Study Timeline

• Study Start: 2020-11-16
• Primary Completion: 2023-11-10
• Study Completion: 2023-11-10
• Study First Submitted: 2024-11-29
• Study First Submitted QC: 2024-11-29
• Study First Posted: 2024-12-04
• Status Verified: 2025-03
• Last Update Submitted: 2025-03-19
• Last Update Posted: 2025-03-24

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Female
• Target Recruitment: 109

Inclusion Criteria

• Age over 18 and under 40 years.

Exclusion Criteria

• Grade III/IV anemia
• Human Immunodeficiency Virus (HIV) infection
• Active bacterial infection
• Opportunistic infection (Tuberculosis, cytomegalovirus (CMV), toxoplasmosis, etc)
• Inability to understand the nature and extent of the study and the procedures required
• Current or recent use of immunosuppressive drugs (corticosteroids, anti-tumor necrosis factors (anti-TNF), methotrexate, etc)
• Active neoplasia

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Pregnant women	Influenza vaccine	Pregnant women receive one dose of influenza-containing vaccine during pregnancy.
Non-pregnant women	Influenza vaccine	Non-pregnant women receive one dose of influenza-containing vaccine.

Primary Outcome Measures

Name	Time	Method
Haemagglutination Inhibition Assay titre	At delivery	Haemagglutination Inhibition Assay (HAI) titres are used to measure responses to relevant influenza strains. The HAI method exploits the property of the influenza virus to haemagglutinate red blood cells. HAI titres are determined as the highest serum dilution inhibiting haemagglutination. An HAI titre of \>=40 is considered protective in adults.; HAI titres will be measured in : * Pregnant women; * In umbilical cord blood

Secondary Outcome Measures

Name	Time	Method
Haemagglutination inhibition assay titre	up to 11 months after vaccination	Haemagglutination Inhibition Assay (HAI) titres are used to measure responses to relevant influenza strains. The HAI method exploits the property of the influenza virus to haemagglutinate red blood cells. HAI titres are determined as the highest serum dilution inhibiting haemagglutination. An HAI titre of \>=40 is considered protective in adults.; HAI titres will be measured in : * Pregnant women: at day of vaccination, day 7 post-vaccination, day 28 post-vaccination, at delivery, week 6 and 12 post-delivery; * Non-pregnant women: at day of vaccination, day 7, day 28, and Month 6 post-vaccination
Micro neutralization assay titre	up to 11 months after vaccination	Micro neutralization assay (MNA) titres are measured on serum samples with detectable HAI titres to determine cross reactivity to related virus strains. This method assesses the ability of serum antibodies to prevent virus from infecting a single layer of cells in a micro titre plate.; MNA titres will be measured in : * Pregnant women: at day of vaccination, day 7 post-vaccination, day 28 post-vaccination, at delivery, week 6 and 12 post-delivery; * Non-pregnant women: at day of vaccination, day 7, day 28, and Month 6 post-vaccination
Influenza virus specific IgG titre	up to 11 month after vaccination	IgG titres specific to influenza virus Hemagglutinin (HA) and Neuraminidase (NA) are measured using conventional Enzyme-linked immunosorbent assay (ELISA) methods. The Enzyme-Linked Lectin Assay (ELLA) is used for detection of NA-specific antibodies only, using reverse genetics viruses with irrelevant HA to ensure only NA antibodies are measured. ELLA is an ELISA variant but adapted to measure the concentration of antibody to NA, determining the amount of sialic acid cleaved from fetuin.; IgG titres specific to Influenza Antigens will be assessed by ELISA and ELLA in: * Pregnant women: at day of vaccination, day 7 post-vaccination, day 28 post-vaccination, at delivery, week 6 and 12 post-delivery; * Non-pregnant women: at day of vaccination, day 7, day 28, and Month 6 post-vaccination
Influenza virus specific IgG antibody avidity	up to 11 months after vaccination	IgG avidity will be measured using chaotropic salts.; IgG avidity will be assessed in : * Pregnant women: at day of vaccination, day 7 post-vaccination, day 28 post-vaccination, at delivery, week 6 and 12 post-delivery; * Non-pregnant women: at day of vaccination, day 7, day 28, and Month 6 post-vaccination

Trial Locations

Locations (1)

CHU Saint-Pierre; 🇧🇪 Brussels, Belgium