Effect of Lactobacillus on the Microbiome of Household Contacts Exposed to COVID-19

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the effect of the probiotic Lactobacillus rhamnosus GG (LGG) and the effect of COVID-19 on the microbiome (the microorganisms that live in and on the human body) in exposed household contacts of COVID-19. This is a randomized, double-blind, placebo-controlled study, meaning subjects will be randomly assigned to receive LGG or a placebo (an inactive substance given in the same form as the active substance) and will not know which product they are receiving. Subjects will participate in the study for around 60 days. All subjects must refrain from taking any other probiotics while on study. All subjects must have access to e-mail and the internet to complete study questionnaires. Participation in this study entails taking LGG/placebo for 28 days, responding to questionnaires, and providing stool and nasal swab samples.

Official Title
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A Randomized Trial of the Effect of Lactobacillus on the Microbiome of Household Contacts Exposed to COVID-19

Conditions
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Microbiome

Intervention / Treatment
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* Dietary Supplement: Lactobacillus rhamnosus GG
* Dietary Supplement: Lactobacillus rhamnosus GG Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age >=1 year (as children <1 year may not be able to take oral probiotics) Household contact of someone diagnosed with COVID-19 Willingness to stop taking other probiotics or to not take any other probiotic while on LGG/placebo (taking a probiotic at the time of screening will not be considered a reason for exclusion. However, subjects will be asked to stop taking their probiotic if they enroll on the study). Access to e-mail/internet to complete electronic consent via REDCap Exclusion Criteria: Symptoms of COVID-19 at enrollment, including: Fever Respiratory symptoms GI symptoms Anosmia Ageusia ->7 days since original patient associated with household contact was diagnosed with COVID-19 Taking hydroxychloroquine or remdesivir for any reason (as this would have the potential to decrease the expected rate of COVID-19 in this population and affect our power and sample size calculations) Enrolled in a COVID-19 prophylaxis study (as this would have the potential to decrease the expected rate of COVID-19 in this population and affect our power and sample size calculations) Any medical condition that would prevent taking oral probiotics or increase risks associated with probiotics including but not limited to: Inability to swallow/aspiration risk and no other methods of delivery (e.g., no G/J tube) Increased infection risk due to immunosuppression due to: Chronic immunosuppressive medication Prior organ or hematopoietic stem cell transplant Known neutropenia (ANC <500 cells/ul) HIV and CD4 <200 cells/ul Increased infection risk due to endovascular due to: Rheumatic heart disease Congenital heart defect, Mechanical heart valves Endocarditis Endovascular grafts Permanent endovascular devices such as permanent (not short-term) hemodialysis catheters, pacemakers, or defibrillators Increased infection risk due to mucosal gastrointestinal due to: Gastroesophageal or intestinal injury, including active bleeding

Ages Eligible for Study
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Minimum Age: 1 Year

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: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: LGG Arm<br>Participants in this arm will be given LGG for 28 days. | Dietary Supplement: Lactobacillus rhamnosus GG<br>* Participants will take 2 capsules per day of either LGG or placebo.<br>|
| Placebo Comparator: Placebo<br>Participants in this arm will be given a placebo for 28 days. | Dietary Supplement: Lactobacillus rhamnosus GG Placebo<br>* Participants will take 2 capsules per day of LGG placebo<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of one or more symptoms of COVID-19 during the study period | Incidence of one or more symptoms of COVID-19 (fever, chills, headache, muscle aches, runny nose, sore throat, cough, shortness of breath, nausea or vomiting, diarrhea, stomach upset or pain, excessive bloating or gas, constipation, loss of sense of smell, loss of sense of taste, rash, painful toes, or other symptoms related to COVID-19 diagnosis) during the study period | 60 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of laboratory-confirmed COVID-19 during the study period | Incidence of laboratory-confirmed COVID-19 (all based on medically-dictated, clinical testing and electronic medical record review) or research laboratory-confirmed COVID-19 (all, based on research testing of nasal swab and stool samples) during the study period | 60 days | 
| Complications of COVID-19 | Complications of COVID-19 (e.g., need for hospitalization, intubation, mortality) during the study period | 60 days | 
| Types of symptoms of COVID-19 | Types of symptoms of COVID-19 during the study period (e.g., fever, chills, headache, muscle aches, runny nose, sore throat, cough, shortness of breath, nausea or vomiting, diarrhea, stomach upset or pain, excessive bloating or gas, constipation, loss of sense of smell, loss of sense of taste, rash, painful toes, or other symptoms related to COVID-19 diagnosis) | 60 days | 
| Duration of symptoms of COVID-19 | Duration of symptoms (days) of COVID-19 during the study period | 60 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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COVID-19, Lactobacillus rhmanosus GG