Post-Acute COVID-19 SyndromePhase 2PURE-LCNCT06643299
Probiotic Use for Recovery Enhancement From Long COVID-19
A Phase 2 study testing Probiotic Agent in people with Post-Acute COVID-19 Syndrome, run by Rush University Medical Center at 1 site in United States.
Trial summary
The goal of this clinical trial is to learn if probiotics can improve symptoms and quality of life in participants with Long COVID. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Post-Acute COVID-19 Syndrome
- What is being tested?
- Probiotic Agent
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 194 participants
- Where
- 1 siteUnited States
- Study dates
- 13 May 2025to 2 Jul 2026
- Phase
- Phase 2
- Are there results?
- None posted in the registry
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 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age ≥18 years who report Long COVID with persistent symptoms at the time of study initiation
Who cannot join
- No longer have symptoms consistent with LC
- Are unable to take the study medication daily
- Are currently pregnant or planning to become pregnant over the course of the study
- Are currently breastfeeding
- Have been diagnosed with an immune-compromising condition
- Are currently taking immunosuppressants
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- Do not speak English as a primary language
- Are regularly taking probiotics
- Are enrolled in another Long COVID study with an intervention
Trial locations and contacts
1 site in 1 country.
United States1 site
Rush University Medical Center
Chicago, Illinois, 60612
About this study
Official title: PURE-LC - Probiotic Use for Recovery Enhancement From Long COVID
The goal of this clinical trial is to learn if probiotics can improve symptoms and quality of life in participants with Long COVID.
Read the detailed description
The goal of this clinical trial is to learn if probiotics can improve symptoms and quality of life in participants with Long COVID. The main questions it aims to answer are:
- Do probiotics reduce the number and severity of symptoms in those with Long COVID?
- Do probiotics improve the physical and mental health quality of life in those with Long COVID?
- Do probiotics improve return to work and daily activities in those with Long COVID?
Researchers will compare probiotics to a placebo (a look-alike substance that contains no probiotics) to see if probiotics work to treat Long COVID.
Participants will take the study medication (placebo or probiotic) for 4 months. They will then cross over (take the other medication) for an additional 4 months. Participants will complete a survey at baseline, 4 months, and 8 months.
- Conditions
- Post-Acute COVID-19 Syndrome
- Being tested
- Probiotic Agent, Placebo
- Keywords
- Long COVID, Post-Acute Sequelae of COVID
- Medical subject headings
- Post-Acute COVID-19 Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Probiotic AgentDrug
Also called BlueBiotics: Ultimate Care
BlueBiology: Ultimate Care probiotic pill taken once daily for a four-month period.
PlaceboOther
Placebo produced to be identical in taste and appearance to the probiotic agent, taken once daily for a four-month period.
| Study group | Role | What they receive |
|---|---|---|
| Probiotic Arm | Active comparator | Probiotic pill taken once daily Receives: Drug: Probiotic Agent |
| Placebo Arm | Placebo comparator | Identical placebo pill taken once daily Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference in Long COVID Severity
Defined as the percentage change from moderate-to-severe Long COVID to mild Long COVID using the Long COVID Symptoms and Severity Score (LC-SSS) tool between groups with subgroup analysis by Long COVID trajectory
Measured: Baseline, Four, and Eight Months
Secondary outcomes (3)
Difference in LC-SSS Total Score
Defined as the change in the LC-SSS total score between groups with subgroup analysis by individual symptom scores and Long COVID trajectory
Measured: Baseline, Four, and Eight Months
Difference in Quality of Life
Defined as the change in score for PROMIS-29 physical and mental health and the PROMIS SF-Cognitive Function 8a scale between groups with subgroup analysis by Long COVID trajectory
Measured: Baseline, Four, and Eight Months
Difference in Return to Work and Activity
Defined as the change in the Work Productivity and Activity Impairment tool scores between groups with subgroup analysis by Long COVID trajectory
Measured: Baseline, Four, and Eight Months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Oct 2024
- Study start13 May 2025
- Primary completion2 Jul 2026
- Study completion2 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Post-Acute COVID-19 SyndromeStudies of the same condition, open and under way.
- More trials run by Rush University Medical CenterThe sponsor's other registered studies.
- 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
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 194 participants (actual)
Sponsor and investigators
- Lead sponsor
- Rush University Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Michael Gottlieb, Rush University Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06643299
- Sponsor's protocol ID
- 24082903
- Acronym
- PURE-LC
- Status last verified
- Aug 2026
- First submitted
- 14 Oct 2024
- Last updated
- 7 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 7 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- PURE-LC - Probiotic Use for Recovery Enhancement From Long COVID
- ClinicalTrials.gov ID
- NCT06643299
- Acronym / sponsor ID
- PURE-LC / 24082903
- Conditions
- Post-Acute COVID-19 Syndrome
- Keywords
- Long COVID, Post-Acute Sequelae of COVID
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 194 participants (actual)
- Lead sponsor
- Rush University Medical CenterUniversity, hospital or other
- Study start
- 13 May 2025 (actual)
- Primary completion
- 2 Jul 2026 (actual)
- Study completion
- 2 Jul 2026 (actual)
- First posted
- 16 Oct 2024 (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.
The goal of this clinical trial is to learn if probiotics can improve symptoms and quality of life in participants with Long COVID.
Detailed description
The goal of this clinical trial is to learn if probiotics can improve symptoms and quality of life in participants with Long COVID. The main questions it aims to answer are:
- Do probiotics reduce the number and severity of symptoms in those with Long COVID?
- Do probiotics improve the physical and mental health quality of life in those with Long COVID?
- Do probiotics improve return to work and daily activities in those with Long COVID?
Researchers will compare probiotics to a placebo (a look-alike substance that contains no probiotics) to see if probiotics work to treat Long COVID.
Participants will take the study medication (placebo or probiotic) for 4 months. They will then cross over (take the other medication) for an additional 4 months. Participants will complete a survey at baseline, 4 months, and 8 months.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Probiotic Arm | Active comparator | Drug: Probiotic AgentProbiotic pill taken once daily |
| Placebo Arm | Placebo comparator | Other: PlaceboIdentical placebo pill taken once daily |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Age ≥18 years who report Long COVID with persistent symptoms at the time of study initiation
Key exclusion criteria (9 listed)
- No longer have symptoms consistent with LC
- Are unable to take the study medication daily
- Are currently pregnant or planning to become pregnant over the course of the study
- Are currently breastfeeding
- Have been diagnosed with an immune-compromising condition
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 |
|---|---|---|
| Probiotic AgentAlso: BlueBiotics: Ultimate CareBlueBiology: Ultimate Care probiotic pill taken once daily for a four-month period. | Drug | Probiotic Arm |
| PlaceboPlacebo produced to be identical in taste and appearance to the probiotic agent, taken once daily for a four-month period. | Other | Placebo Arm |
Primary outcome
Difference in Long COVID Severity
Time frame: Baseline, Four, and Eight Months
Defined as the percentage change from moderate-to-severe Long COVID to mild Long COVID using the Long COVID Symptoms and Severity Score (LC-SSS) tool between groups with subgroup analysis by Long COVID trajectory
3 secondary outcomes
Difference in LC-SSS Total Score
Time frame: Baseline, Four, and Eight Months
Difference in Quality of Life
Time frame: Baseline, Four, and Eight Months
Difference in Return to Work and Activity
Time frame: Baseline, Four, and Eight Months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Aug 2026.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Probiotic Agent in people with Post-Acute COVID-19 Syndrome, run by Rush University Medical Center at 1 site in United States.
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 1 inclusion and 9 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: finished, as of the sponsor's last update on 7 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference in Long COVID Severity (time frame: Baseline, Four, and Eight Months). 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 7 Aug 2026.