Immunoglobulins, Influenza, Maternal-Fetal Relations, Vaccination; Infection
Conditions
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;
Interventions
BIOLOGICALInfluenza vaccine
Alpharix-Tetra®, Vaxigrip Tetra® and Influvac Tetra® were used as influenza vaccines in the 2020-2021, 2021-2022, and 2022-2023 seasons respectively.
Sponsors
Université Libre de Bruxelles
Centre Hospitalier Universitaire Saint Pierre
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Outcomes Assessor)
Masking description
Researchers analyzing the immunological outcomes are blinded to the groups of the subjects (pregnant vs non-pregnant).
Intervention model description
Pregnant women and non-pregnant women are recruited in parallel.
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 40 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Haemagglutination Inhibition Assay titre | 28 days post 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 * Non-pregnant women |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| 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 |
Countries
Belgium
Outcome results
None listed