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| Name | Class |
|---|---|
| Université Libre de Bruxelles | OTHER |
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The overall objective of the project is to determine the impact of pregnancy on the response to influenza immunization.
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:
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Pregnant women | Active Comparator | Pregnant women receive one dose of influenza-containing vaccine during pregnancy. |
|
| Non-pregnant women | Active Comparator | Non-pregnant women receive one dose of influenza-containing vaccine. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Influenza vaccine | Biological | Alpharix-Tetra®, Vaxigrip Tetra® and Influvac Tetra® were used as influenza vaccines in the 2020-2021, 2021-2022, and 2022-2023 seasons respectively. |
| Measure | Description | Time Frame |
|---|---|---|
| Haemagglutination Inhibition Assay titre | 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 :
| 28 days post vaccination |
| Haemagglutination Inhibition Assay titre | 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 :
| At delivery |
| Measure | Description | Time Frame |
|---|---|---|
| Haemagglutination inhibition assay titre | 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 :
|
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Inclusion Criteria:
Exclusion Criteria:
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| CHU Saint-Pierre | Brussels | 1000 | Belgium |
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| ID | Term |
|---|---|
| D007239 | Infections |
| D007251 | Influenza, Human |
| ID | Term |
|---|---|
| D012141 | Respiratory Tract Infections |
| D009976 | Orthomyxoviridae Infections |
| D012327 | RNA Virus Infections |
| D014777 | Virus Diseases |
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| ID | Term |
|---|---|
| D007252 | Influenza Vaccines |
| ID | Term |
|---|---|
| D014765 | Viral Vaccines |
| D014612 | Vaccines |
| D001688 | Biological Products |
| D045424 | Complex Mixtures |
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Pregnant women and non-pregnant women are recruited in parallel.
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Researchers analyzing the immunological outcomes are blinded to the groups of the subjects (pregnant vs non-pregnant).
| up to 11 months after vaccination |
| Micro neutralization assay titre | 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 :
| up to 11 months after vaccination |
| Influenza virus specific IgG titre | 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:
| up to 11 month after vaccination |
| Influenza virus specific IgG antibody avidity | IgG avidity will be measured using chaotropic salts. IgG avidity will be assessed in :
| up to 11 months after vaccination |
| D012140 | Respiratory Tract Diseases |