Effect of Immune X on Common Cold Incidence in Healthy Adults (CELFI)

The Effect of Immune X on the Incidence of the Common Cold in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled Trial

The goal of this clinical trial is to learn if Immune X can help prevent common cold events in healthy adults who have a history of upper respiratory tract infections. The main questions it aims to answer are:

• Does Immune X reduce the proportion of participants who experience at least one clinically confirmed common cold event during the study period?
• Does Immune X affect the number, duration, and severity of common cold events?

Researchers will compare Immune X to a placebo (a look-alike capsule containing inactive ingredients) to see if Immune X helps prevent common cold events.

Participants will:

• Take Immune X or placebo daily for 16 weeks during the winter season.
• Attend study visits at the beginning and end of the study and complete questionnaires and symptom assessments throughout the study.
• Record cold symptoms, medications, and other study information using a smartphone application.
• Provide blood and stool samples during the study.

Study Overview

• Status: Not yet recruiting
• Conditions: Common Cold; Upper Respiratory Tract Infection (URTI)
• Intervention / Treatment: Dietary supplement: Immune X; Other: Placebo

• Study Type: Interventional
• Enrollment (Estimated): 160
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Katja A. Schönenberger, PhD; Phone Number: +41 52 354 01 11; Email: katja.schoenenberger@givaudan.com
• Study Contact Backup: Name: Linda Lopez, PhD; Phone Number: +41 52 354 01 11; Email: linda.lopez@givaudan.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Men and women aged 18 to 65 years.
• History of at least two upper respiratory tract infections during the previous winter season.
• Body mass index between 18 and 30 kg/m².
• Generally healthy, as determined by the investigator.
• Women of childbearing potential must have a negative pregnancy test and agree to use an effective method of contraception during the study.
• Covered by French health insurance.
• Able and willing to provide written informed consent.

Exclusion Criteria:

• Current or recent upper respiratory tract infection or COVID-19 infection within 2 weeks before enrollment.
• Acute gastrointestinal infection, including gastroenteritis, within 2 weeks before enrollment.
• Use of non-steroidal anti-inflammatory drugs (NSAIDs) within 2 weeks before enrollment.
• Use of systemic antibiotics within 3 months before enrollment.
• Receipt of any vaccination within 6 weeks before enrollment.
• Surgery requiring general anesthesia within 1 month before enrollment.
• History of chronic respiratory disease, including asthma or chronic obstructive pulmonary disease.
• Food allergy or chronic/recurrent allergic upper airway conditions requiring regular medical treatment, including moderate to severe allergic rhinitis, hay fever, or chronic rhinosinusitis.
• Acute lower respiratory tract infection within 6 months before enrollment or ongoing long COVID.
• Immunodeficiency (including HIV infection) or autoimmune disease, except stable hypothyroidism.
• Severe or uncontrolled chronic disease, including cancer, significant liver, pancreatic, biliary, or renal disease, inflammatory bowel disease, or cardiovascular disease requiring intensive medical management.
• Untreated or inadequately controlled diabetes.
• History or current diagnosis of periodontitis.
• Current chemotherapy, immunosuppressive therapy, or chronic treatment with corticosteroids or opioids.
• Specific diets or major dietary changes within 3 months before enrollment, including high-protein, vegan, low-calorie, or low-FODMAP diets, or participation in a weight-loss program.
• Current use of dietary supplements that may affect immune or gut microbiota parameters, or discontinuation of such supplements less than 6 weeks before enrollment.
• Current smoking or e-cigarette use, or smoking cessation within 6 months before enrollment.
• Current drug or alcohol abuse, or a history of abuse within the previous 12 months.
• Regular consumption of more than 2 alcoholic drinks per day and unwillingness to maintain stable drinking habits during the study.
• Unwillingness to refrain from using over-the-counter cold remedies, nasal washes or sprays, antihistamines, corticosteroids, or NSAIDs during the study.
• More than 8 hours per week of vigorous physical activity or planned major changes in physical activity during the study.
• Any condition or circumstance that, in the investigator's judgment, may place the participant at unacceptable risk or interfere with study participation or interpretation of study results.
• Current participation in another clinical trial or being in an exclusion period from a previous clinical trial.
• Pregnant or breastfeeding.
• Persons deprived of liberty, under legal protection, or unable to provide informed consent.
• Individuals who have reached the regulatory compensation limit for participation in clinical research.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Immune X; 80 participants who meet the eligibility criteria will be randomized to the experimental arm and will receive Immune X for 16 weeks.	Dietary supplement: Immune X; 500 mg Immune X daily as capsules for 16 weeks.
Placebo Comparator: Placebo; 80 participants who meet the eligibility criteria will be randomized to the placebo arm and will receive placebo for 16 weeks.	Other: Placebo; Matching placebo capsules daily for 16 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Participants With at Least One Clinically Confirmed Cold Event	Proportion of participants with at least one clinically confirmed cold event.	Week 2 to Week 16

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Clinically Confirmed Cold Events	Mean number of clinically confirmed cold events per participant.	Week 2 to Week 16
Duration of Clinically Confirmed Cold Events	Duration of clinically confirmed cold events measured in days.	Week 2 to Week 16
Upper Respiratory Symptoms of Clinically Confirmed Cold Events	Wisconsin Upper Respiratory Symptom Survey (WURSS-24): Zero is equivalent to no symptoms and 7 indicates severe.	Week 2 to Week 16
Cold Symptoms of Clinically Confirmed Cold Events	Jackson Cold Scale: 0 is equivalent to absent symptoms and 3 indicates severe symptoms	Week 2 to Week 16
Illness-Specific Quality of Life During Cold Events	Wisconsin Upper Respiratory Symptom Survey (WURSS-24) quality-of-life score: Zero is equivalent to no interference and 7 indicates severe interference.	Week 2 to Week 16
Time to First Clinically Confirmed Cold Event	Number of days from Day 15 after randomization to the first clinically confirmed cold event.	Week 2 to Week 16
Fatigue	Chalder Fatigue Questionnaire (CFQ-11) total score: 0 is equivalent to less/better than usual and 33 indicates much more/much worse than usual.	Baseline, Weeks 4, 8, 12, and 16
Use of Rescue Medication During Cold Events	Number of doses and duration of rescue medication use during cold events.	Week 2 to Week 16
Number of Cold Events (Clinically Confirmed and Unconfirmed)	Mean number of clinically confirmed and unconfirmed cold events per participant.	Week 2 to Week 16
Adverse Events	Number of participants with adverse events.	Baseline through Week 16

Collaborators and Investigators

• Sponsor: Givaudan France Naturals
• Collaborators: CEN Expérimental
• Investigators: Principal Investigator: Carole Perrin, MD, Cen Experimental

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): April 30, 2027
• Study Completion (Estimated): April 30, 2027

Study Registration Dates

• First Submitted: August 17, 2026
• First Submitted That Met QC Criteria: August 21, 2026
• First Posted (Actual): August 26, 2026

Study Record Updates

• Last Update Posted (Actual): August 26, 2026
• Last Update Submitted That Met QC Criteria: August 21, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Picornaviridae Infections; Respiratory Tract Infections; Common Cold
• Other Study ID Numbers: C1775; 2026-A00903-48 (Other Identifier: ID-RCB)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No