Probiotics and Influenza Vaccination Response

Study Overview
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Brief Summary
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Assess efficacy of oral ingestion of a probiotic product on immune function in a population of healthy adult men and women in a clinical vaccination study.

Official Title
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Effects of Probiotics in Immune Response to Influenza Vaccination in Adults

Conditions
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Vaccine Response

Intervention / Treatment
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* Dietary Supplement: Probiotic effect on influenza vaccine response


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women Age 16 - 65 y and healthy Self-reported regular Dutch eating habits as assessed by questionnaire (3 main meals per day) No influenza vaccination in 2022 Non-smokers BMI 18.5-28 Adherence to habitual diet no changes during study period Signed informed consent Exclusion Criteria: Recent vaccination Acute or chronic illness (e.g., diabetes mellitus) Gastrointestinal disorders (e.g., inflammatory bowel disease) Acute gastroenteritis in the past 2 months Immunodeficiency disorder Use of immunosuppressive drugs (e.g. cyclosporine, azathioprine, systemic corticosteroids, antibodies) Unexplained weight loss or weight gain of > 3 kg in the 3 months prior to pre-study screening Alcohol or drug abuse Mental status that is incompatible with the proper conduct of the study History of cancer Use of immune boosting supplements within 4 weeks before screening To be extended & specified in protocol phase

Ages Eligible for Study
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Minimum Age: 16 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Probiotic<br>2B Colony Forming Unit/ day | Dietary Supplement: Probiotic effect on influenza vaccine response<br>* Seroconversion rate: the percentage of subjects achieving at least a 4-fold increase or an increase from >10 to 40 in Ab titre for seronegative subjects.<br>|
| Placebo Comparator: Placebo<br>Equivalent placebo | Dietary Supplement: Probiotic effect on influenza vaccine response<br>* Seroconversion rate: the percentage of subjects achieving at least a 4-fold increase or an increase from >10 to 40 in Ab titre for seronegative subjects.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Seroconversion rate | Percentage of subjects achieving at least a 4-fold increase or an increase from >10 to 40 in Antibody titer for seronegative subjects | From baseline to week 6 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in plasma cytokine levels | Change in plasma cytokine levels (IL-10, IL-4, TFN alpha, IFN gamma) | Baseline, week 2 and week 6 | 
| Change in IgA antibodies against influenza | Titer of plasma anti-influenza IgA | baseline, week 2, week 6 | 
| Change in IgG antibodies against influenza | Titer of plasma anti-influenza IgG | baseline, week 2, week 6 | 
| Change in IgM antibodies against influenza | Titer of plasma anti-influenza IgM | baseline, week 2, week 6 | 
| Change in Gastrointestinal symptoms | Gastrointestinal manifestations documented through Gastrointestinal Symptom Rating Scale (GSRS, 7-point graded Likert-type scale and includes 15 items combined into 5 symptom clusters - 1 represents absence of troublesome symptoms and 7 represents very troublesome symptoms) | baseline, week 2, week 6 | 
| Change in Incidence of respiratory infections | Assessment of respiratory infection through questionnaire (4-point graded Likert-type scale and includes 11 items, including the 8 items comprising the Jackson common cold questionnaire - 0 = absent, 1 = mild, 2 = moderate, 3 = severe) | baseline, week 2, week 6 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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vaccine response, seroconversion, antibody