Recurrent Respiratory Tract InfectionsPhase 2NCT07297966
Evaluation of the Clinical Efficacy of Antrrix Probiotics in Improving Recurrent Respiratory Infections in Infants and Young Children
A Phase 2 study testing Probiotic in people with Recurrent Respiratory Tract Infections, run by Min-Tze LIONG at 2 sites in 2 countries.
Trial summary
This study is an 8-weeks, randomized controlled trial involving children under 6 years of age who meet clinical diagnostic criteria for RRTI. Participants are randomized to receive either probiotic or placebo. Read more about this study
- Who is it for?
- Ages 1 day to 6 years
- Conditions the study is for
- Recurrent Respiratory Tract Infections
- What is being tested?
- Probiotic
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 120 participants
- Where
- 2 sitesin 2 countries
- Study dates
- 14 May 2025to 30 Jun 2026
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 1 day to 6 years
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- Age < 6 years, gender not limited;
- Meets the clinical diagnostic criteria for recurrent respiratory tract infections (Clinical Diagnosis and Treatment Pathway for Recurrent Respiratory Tract Infections in Children (2022 Edition) 10 );
- Parents or other legal guardians of the child fully understand the trial and voluntarily sign informed consent forms before the start of any research procedure;
- Willing to discontinue the use of other probiotics during the trial;
- Agree to the collection of fecal biological samples during this trial.
Who cannot join
- Those deemed by the investigator to have poor compliance or be unsuitable for participation;
- Allergic to the investigational product and its components;
- Allergic to respiratory tract infection drugs and their components;
- Respiratory infections caused by underlying diseases such as primary immunodeficiency diseases, acquired immunodeficiency syndrome (ADRS), congenital airway malformations, congenital heart disease, gastroesophageal reflux disease (GERD), and pulmonary dysplasia;
- Patients with severe malnutrition, rickets, and severe primary diseases of the heart, brain, liver, kidney, and hematopoietic systems;
- Use probiotic preparations, antibiotics, immunostimulants, or immunosuppressants 4 weeks before participating in the experiment.
Trial locations and contacts
2 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
2 sites in 2 countries
China1 site, 1 recruiting
- Recruiting
Xinyi City People's Hospital
Xingyi, Guangdong
Sitao Li, MD., +86 135 7055 0735, lisit@mail.sysu.edu.cn
Jie Yuan, M.Sc., 822137027899, peanut.yuan@diprobio.com
Malaysia1 site, 1 recruiting
- Not yet recruiting
Universiti Sains Malaysia
George Town, Pulau Pinang, 11800
Min Tze Liong, Ph.D., 6046532114, mintze.liong@usm.my
Jie Yuan, M.Sc., 822137027899, peanut.yuan@diprobio.com
About this study
This study is an 8-weeks, randomized controlled trial involving children under 6 years of age who meet clinical diagnostic criteria for RRTI. Participants are randomized to receive either probiotic or placebo. The primary clinical outcomes assessed are duration and frequency of respiratory symptoms and quality of life. To investigate potential mechanisms, stool samples were collected pre- and post-intervention for metagenomics gene sequencing to analyze changes in gut microbiota composition and identify specific bacterial taxa associated with clinical improvements.
Read the detailed description
Recurrent respiratory tract infection (RRTI) is a common pediatric condition with an increasing yearly incidence, seriously impacting children's growth, development, and quality of life. Younger children are particularly vulnerable, with notably high incidence rates in those under five years of age. RRTI can hinder physical development, contribute to the emergence of antibiotic resistance, increase school absenteeism, and place significant economic stress on families and the healthcare system. The underlying causes and disease mechanisms of RRTI are multifactorial, involving immune immaturity, environmental exposures, and microbial imbalance. Growing evidence suggests that disruptions in the gut microbiota may influence respiratory health through the gut-lung axis. Probiotics, by supporting microbiota homeostasis and modulating immune responses, have demonstrated potential in reducing the frequency and severity of respiratory infections in children. Given these connections, further investigation into the targeted use of probiotics to improve clinical outcomes in RRTI is essential for advancing preventive and therapeutic strategies in pediatric care.
Some pathways are proposed to explain how probiotics may improve recurrent respiratory tract infections (RRTI). The gastrointestinal tract and respiratory tract are interconnected components of the mucosal immune system. Immune responses generated in the gut can influence distant mucosal sites, including the lungs. Probiotics can stimulate gut-associated lymphoid tissue, leading to enhanced production of antigen-specific immunoglobulins (IgG, IgA), cytokines, and short-chain fatty acids. These immune mediators circulate systemically and contribute to strengthened respiratory defenses. In addition, the respiratory tract possesses its own microbial ecosystem, and maintaining the stability of this respiratory microbiota is essential for safeguarding respiratory health.
Children affected by RRTI often exhibit decreased levels of beneficial bacteria such as Bifidobacteria and Lactobacilli in the intestines. Dysbiosis weakens both local and systemic immunity, particularly through reduced production of immunoglobulins such as IgA. Probiotic supplementation can help restore microbial balance and enhance the host's immune profile. Reported outcomes include fewer and milder respiratory infections, shorter symptom duration, and improved immune parameters such as increased immunoglobulin levels and a more favorable T-cell profile. Importantly, probiotics have demonstrated a strong safety profile in pediatric populations.
Based on current scientific understanding, this project will focus on children under 6 years of age who meet clinical diagnostic criteria for RRTI. Probiotics, containing strains Dipro-CRL1505 and M-16V strains, will be administered for 8 weeks to evaluate clinical benefits and safety outcomes. Additionally, 16S rRNA sequencing will assess gut microbiota composition before treatment, at 4 weeks, and at 8 weeks. Through these combined clinical and microbiological measures, the study aims to clarify the therapeutic potential and underlying mechanisms of this probiotic intervention in children with RRTI.
- Conditions
- Recurrent Respiratory Tract Infections
- Being tested
- Probiotic, Placebo
- Keywords
- RRTI, probiotic, RCT, children
- Medical subject headings
- Respiratory Tract Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ProbioticDietary supplement
Daily 2 × 10 9 CFU per 6 drops containing Lactobacillus rhamnosus CRL1505+Bifidobacterium brevis M-16V strain in MCT oil
PlaceboDietary supplement
Daily 6 drops MCT oil without probiotics
| Study group | Role | What they receive |
|---|---|---|
| Probiotic | Experimental | Daily 2 × 10 9 CFU per 6 drops containing Lactobacillus rhamnosus CRL1505+Bifidobacterium brevis M-16V strain in MCT oil Receives: Dietary Supplement: Probiotic |
| Placebo | Placebo comparator | Daily 6 drops of MCT oil without probiotic Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Respiratory symptoms in children upon administration of probiotic or placebo as assessed via clinical questionnaire
Differences in severity of respiratory symptoms in children upon administration of probiotic or placebo, assessed using a hospital-based clinical questionnaire scored on a 5-point ordinal scale (0 = no symptoms to 4 = severe symptoms), with lower scores indicating better respiratory status.
Measured: day 1, day 7, day 14, week 4, week 8
Secondary outcomes (3)
Quality of life in children upon administration of probiotic or placebo via clinical questionnaire
Differences in quality of life in children upon administration of probiotic or placebo, assessed using a hospital-based caregiver-reported clinical questionnaire scored on a 5-point ordinal scale, with lower scores indicating better quality of life.
Measured: day 1, day 7, day 14, week 4, week 8
Microbiota profiles of fecal samples in young children upon administration of probiotic, lactulose or their combinations as assessed via metagenomics sequencing
Differences in microbiota profiles in fecal sample of children upon administration of probiotic or placebo
Measured: day 1, day 7, day 14, week 4, week 8
Immune biomarker profiles of fecal samples in young children upon administration of probiotic, lactulose or their combinations as assessed via Enzyme-Linked Immunosorbent Assay (ELISA)
Differences in immune biomarker profiles in fecal sample of children such as sIgA upon administration of probiotic or placebo
Measured: day 1, day 7, day 14, week 4, week 8
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Dec 2025
- Study start14 May 2025
- Primary completion30 Jun 2026 (estimated)
- Study completion30 Jun 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Recurrent Respiratory Tract InfectionsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 120 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Min-Tze LIONG
- Sponsor type
- University, hospital or other
- Collaborators
- Xinyi City People's Hospital
- Responsible party
- Sponsor-investigator, Min-Tze LIONG, Universiti Sains Malaysia
- Investigators
- Sitao Li, MD., Principal investigator, The Sixth Affiliated Hospital of Sun Yat-sen University, Xinyi People's Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07297966
- Sponsor's protocol ID
- (2024)-0001
- Status last verified
- Dec 2025
- First submitted
- 8 Dec 2025
- Last updated
- 17 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of the Clinical Efficacy of Antrrix Probiotics in Improving Recurrent Respiratory Infections in Infants and Young Children
- ClinicalTrials.gov ID
- NCT07297966
- Acronym / sponsor ID
- (2024)-0001
- Conditions
- Recurrent Respiratory Tract Infections
- Keywords
- RRTI, probiotic, RCT, children
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 120 participants (estimated)
- Lead sponsor
- Min-Tze LIONGUniversity, hospital or other
- Collaborators
- Xinyi City People's Hospital
- Study start
- 14 May 2025 (actual)
- Primary completion
- 30 Jun 2026 (estimated)
- Study completion
- 30 Jun 2026 (estimated)
- First posted
- 22 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study is an 8-weeks, randomized controlled trial involving children under 6 years of age who meet clinical diagnostic criteria for RRTI. Participants are randomized to receive either probiotic or placebo. The primary clinical outcomes assessed are duration and frequency of respiratory symptoms and quality of life. To investigate potential mechanisms, stool samples were collected pre- and post-intervention for metagenomics gene sequencing to analyze changes in gut microbiota composition and identify specific bacterial taxa associated with clinical improvements.
Detailed description
Recurrent respiratory tract infection (RRTI) is a common pediatric condition with an increasing yearly incidence, seriously impacting children's growth, development, and quality of life. Younger children are particularly vulnerable, with notably high incidence rates in those under five years of age. RRTI can hinder physical development, contribute to the emergence of antibiotic resistance, increase school absenteeism, and place significant economic stress on families and the healthcare system. The underlying causes and disease mechanisms of RRTI are multifactorial, involving immune immaturity, environmental exposures, and microbial imbalance. Growing evidence suggests that disruptions in the gut microbiota may influence respiratory health through the gut-lung axis. Probiotics, by supporting microbiota homeostasis and modulating immune responses, have demonstrated potential in reducing the frequency and severity of respiratory infections in children. Given these connections, further investigation into the targeted use of probiotics to improve clinical outcomes in RRTI is essential for advancing preventive and therapeutic strategies in pediatric care.
Some pathways are proposed to explain how probiotics may improve recurrent respiratory tract infections (RRTI). The gastrointestinal tract and respiratory tract are interconnected components of the mucosal immune system. Immune responses generated in the gut can influence distant mucosal sites, including the lungs. Probiotics can stimulate gut-associated lymphoid tissue, leading to enhanced production of antigen-specific immunoglobulins (IgG, IgA), cytokines, and short-chain fatty acids. These immune mediators circulate systemically and contribute to strengthened respiratory defenses. In addition, the respiratory tract possesses its own microbial ecosystem, and maintaining the stability of this respiratory microbiota is essential for safeguarding respiratory health.
Children affected by RRTI often exhibit decreased levels of beneficial bacteria such as Bifidobacteria and Lactobacilli in the intestines. Dysbiosis weakens both local and systemic immunity, particularly through reduced production of immunoglobulins such as IgA. Probiotic supplementation can help restore microbial balance and enhance the host's immune profile. Reported outcomes include fewer and milder respiratory infections, shorter symptom duration, and improved immune parameters such as increased immunoglobulin levels and a more favorable T-cell profile. Importantly, probiotics have demonstrated a strong safety profile in pediatric populations.
Based on current scientific understanding, this project will focus on children under 6 years of age who meet clinical diagnostic criteria for RRTI. Probiotics, containing strains Dipro-CRL1505 and M-16V strains, will be administered for 8 weeks to evaluate clinical benefits and safety outcomes. Additionally, 16S rRNA sequencing will assess gut microbiota composition before treatment, at 4 weeks, and at 8 weeks. Through these combined clinical and microbiological measures, the study aims to clarify the therapeutic potential and underlying mechanisms of this probiotic intervention in children with RRTI.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Probiotic | Experimental | Dietary Supplement: ProbioticDaily 2 × 10 9 CFU per 6 drops containing Lactobacillus rhamnosus CRL1505+Bifidobacterium brevis M-16V strain in MCT oil |
| Placebo | Placebo comparator | Dietary Supplement: PlaceboDaily 6 drops of MCT oil without probiotic |
Who may qualify
- Ages
- 1 day to 6 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (5 listed)
- Age < 6 years, gender not limited;
- Meets the clinical diagnostic criteria for recurrent respiratory tract infections (Clinical Diagnosis and Treatment Pathway for Recurrent Respiratory Tract Infections in Children (2022 Edition) 10 );
- Parents or other legal guardians of the child fully understand the trial and voluntarily sign informed consent forms before the start of any research procedure;
- Willing to discontinue the use of other probiotics during the trial;
- Agree to the collection of fecal biological samples during this trial.
Key exclusion criteria (6 listed)
- Those deemed by the investigator to have poor compliance or be unsuitable for participation;
- Allergic to the investigational product and its components;
- Allergic to respiratory tract infection drugs and their components;
- Respiratory infections caused by underlying diseases such as primary immunodeficiency diseases, acquired immunodeficiency syndrome (ADRS), congenital airway malformations, congenital heart disease, gastroesophageal reflux disease (GERD), and pulmonary dysplasia;
- Patients with severe malnutrition, rickets, and severe primary diseases of the heart, brain, liver, kidney, and hematopoietic systems;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ProbioticDaily 2 × 10 9 CFU per 6 drops containing Lactobacillus rhamnosus CRL1505+Bifidobacterium brevis M-16V strain in MCT oil | Dietary supplement | Probiotic |
| PlaceboDaily 6 drops MCT oil without probiotics | Dietary supplement | Placebo |
Primary outcome
Respiratory symptoms in children upon administration of probiotic or placebo as assessed via clinical questionnaire
Time frame: day 1, day 7, day 14, week 4, week 8
Differences in severity of respiratory symptoms in children upon administration of probiotic or placebo, assessed using a hospital-based clinical questionnaire scored on a 5-point ordinal scale (0 = no symptoms to 4 = severe symptoms), with lower scores indicating better respiratory status.
3 secondary outcomes
Quality of life in children upon administration of probiotic or placebo via clinical questionnaire
Time frame: day 1, day 7, day 14, week 4, week 8
Microbiota profiles of fecal samples in young children upon administration of probiotic, lactulose or their combinations as assessed via metagenomics sequencing
Time frame: day 1, day 7, day 14, week 4, week 8
Immune biomarker profiles of fecal samples in young children upon administration of probiotic, lactulose or their combinations as assessed via Enzyme-Linked Immunosorbent Assay (ELISA)
Time frame: day 1, day 7, day 14, week 4, week 8
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Apr 2026.
- Individual participant dataSharing planned: No
Related trials for Recurrent Respiratory Tract Infections
Not yet recruitingPhase 2
Combination Bevacizumab and PRGN-2012 in Adults With Recurrent Respiratory Papillomatosis (RRP)
Respiratory Recurrent Papillomatosis (RRP), Human Papillomavirus (HPV)
RecruitingObservational study
Natural History, Management, and Genetics of the Hyperimmunoglobulin E Recurrent Infection Syndrome (HIES)
Infections, Pneumonia
Active, not recruitingPhase 2
Bevacizumab in Adults With Recurrent Respiratory Papillomatosis (RRP)
Respiratory Tract Diseases, Neoplasms
Not yet recruitingPhase 3
Zopapogene Imadenovec for the Treatment of Recurrent Respiratory Papillomatosis in Children
Recurrent Respiratory Papillomatosis (RRP), Juvenile-onset Recurrent Respiratory Papillomatosis
RecruitingObservational study
Rare Disease Patient Registry & Natural History Study - Coordination of Rare Diseases at Sanford
Rare Disorders, Undiagnosed Disorders
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Sitao Li, MD. principal investigator
The Sixth Affiliated Hospital of Sun Yat-sen University, Xinyi People's Hospital
2 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Probiotic in people with Recurrent Respiratory Tract Infections, run by Min-Tze LIONG at 2 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 17 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in China, Malaysia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Min-Tze Liong, Ph.D. (6046532114, mintze.liong@usm.my), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Respiratory symptoms in children upon administration of probiotic or placebo as assessed via clinical questionnaire (time frame: day 1, day 7, day 14, week 4, week 8). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Apr 2026.