COVID-19NCT07610512
Immunomodulatory Effect of Probiotics on the Immunogenicity of Anti-SARS-CoV-2 Vaccines
A study testing Probiotics in people with COVID-19 and Immune Response, run by Grape King Bio Ltd. at 1 site in Taiwan.
Trial summary
This study aims to evaluate whether oral probiotic supplementation can modulate the immune response induced by COVID-19 vaccination. Specifically, the study will assess the effects of probiotics on vaccine-induced antibody responses and cellular immune responses, and explore whether probiotics may enhance or… Read more about this study
- Who is it for?
- Ages 20 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- COVID-19, Immune Response
- What is being tested?
- Probiotics
- Type of treatment
- Vaccines, Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 138 participants
- Where
- 1 siteTaiwan
- Study dates
- 13 Oct 2021to 31 Mar 2022
- Phase
- Interventional
- 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 20 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Male or female subject ≥ 20 to ≤ 65 years of age at the time signing informed consent form.
- Body weight ≥50 kgs
- Must be scheduling to receive a BNT162b2 mRNA COVID-19 vaccine
- Being able to comply with the study protocol
- Being able to independently provide written informed consent
Who cannot join
- Taking antibiotic at enrollment
- Taking immunomodulatory (e.g., steroid) or anti-histamine drugs
- Took pre- or probiotics within the past 30 days
- Being to expected to take other probiotic supplement during the study period
- Being expected to take antibiotic during the study period
- A history of hypersensitivity or severe allergic reaction to any components of the probiotics or placebo supplement
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- Pregnant or breastfeeding
- Having a severe immunocompromised disorder (e.g. HIV infection)
- Solid organ or bone marrow transplant recipients
- Major gastrointestinal surgery within 3 months before enrollment
- Having severe active gastrointestinal conditions, including inflammatory bowel disease or diverticulitis
- No self-reported symptoms of an upper airway infection with the past 2 weeks
- A history of SARS-CoV-2 infection
- Previously participated in investigational study involving SARS-CoV-2 vaccines or therapies
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Prospective Study to Determine the Immunomodulatory Effect of Probiotics on the Immunogenicity of Anti-SARS-CoV-2 Vaccine Recipients Study.
This study aims to evaluate whether oral probiotic supplementation can modulate the immune response induced by COVID-19 vaccination. Specifically, the study will assess the effects of probiotics on vaccine-induced antibody responses and cellular immune responses, and explore whether probiotics may enhance or accelerate immunity and reduce vaccine-related adverse effects. A total of 140 participants are planned to be enrolled.
Read the detailed description
Large-scale clinical trials have demonstrated that COVID-19 vaccines effectively reduce the incidence of COVID-19, as well as the risk of severe disease and mortality. These protective effects are primarily mediated through vaccine-induced immune responses, including both humoral immunity (antibody production) and cellular immunity.
Probiotics are widely recognized for their potential health benefits and are commonly consumed in foods such as yogurt. Emerging evidence suggests that probiotic supplementation may enhance immune responses to vaccination, as demonstrated in studies involving influenza vaccines.
This study is designed to investigate whether oral probiotic supplementation can modulate the immune response to COVID-19 vaccination. The study will evaluate both antibody responses and cellular immune responses following vaccination, and assess whether probiotics can enhance or accelerate the development of vaccine-induced immunity. In addition, the study will explore whether probiotic supplementation may reduce vaccine-related adverse effects.
A total of 140 participants are planned to be enrolled in this study.
- Conditions
- COVID-19, Immune Response
- Being tested
- Probiotics, Placebo
- Medical subject headings
- COVID-19
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ProbioticsDietary supplement
Also called Lactobacillus spp., Probiotic supplement, Lactic acid bacteria
Oral probiotic capsules containing Lactobacillus spp. administered once daily for 4-5 weeks following COVID-19 vaccination to evaluate immunomodulatory effects on vaccine-induced immune responses.
PlaceboOther
Matching placebo capsules containing microcrystalline cellulose administered once daily for 4-5 weeks following COVID-19 vaccination. The placebo is identical in appearance, packaging, and schedule to the probiotic capsules.
| Study group | Role | What they receive |
|---|---|---|
| Probiotic Group | Experimental | Participants will receive oral probiotic capsules containing Lactobacillus spp. once daily for 4-5 weeks following COVID-19 vaccination. The intervention is administered to evaluate the immunomodulatory effects of probiotics on vaccine-induced humoral and cellular immune responses. Receives: Dietary Supplement: Probiotics |
| Placebo Group | Placebo comparator | Participants will receive matching placebo capsules containing microcrystalline cellulose once daily for 4-5 weeks following COVID-19 vaccination. The placebo is identical in appearance, packaging, and administration schedule to the probiotic capsules. Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
SARS-CoV-2 spike protein-specific IgG antibody level
Change in SARS-CoV-2 spike protein-specific IgG antibody levels following COVID-19 vaccination between probiotic and placebo groups.
Measured: Baseline (Day 0-7 before vaccination), Day 14 (±4 days), and Day 28 (±4 days) after first dose of BNT162b2 vaccination
SARS-CoV-2-specific T cell immune response at Day 14 after vaccination.
Assessment of vaccine-induced cellular immune response measured by antigen-specific T cell activation between probiotic and placebo groups.
Measured: Baseline and Day 14 (±4 days) after vaccination
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 May 2026
- Study start13 Oct 2021
- Primary completion31 Mar 2022
- Study completion31 Mar 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for COVID-19Studies 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 N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 138 participants (actual)
Sponsor and investigators
- Lead sponsor
- Grape King Bio Ltd.
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Taipei Medical University Hospital
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07610512
- Sponsor's protocol ID
- N202109037
- Status last verified
- May 2026
- First submitted
- 21 May 2026
- Last updated
- 3 Jun 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 3 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Prospective Study to Determine the Immunomodulatory Effect of Probiotics on the Immunogenicity of Anti-SARS-CoV-2 Vaccine Recipients Study.
- ClinicalTrials.gov ID
- NCT07610512
- Acronym / sponsor ID
- N202109037
- Conditions
- COVID-19, Immune Response
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 138 participants (actual)
- Lead sponsor
- Grape King Bio Ltd.Industry (pharma, biotech, devices)
- Collaborators
- Taipei Medical University Hospital
- Study start
- 13 Oct 2021 (actual)
- Primary completion
- 31 Mar 2022 (actual)
- Study completion
- 31 Mar 2022 (actual)
- First posted
- 28 May 2026 (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 aims to evaluate whether oral probiotic supplementation can modulate the immune response induced by COVID-19 vaccination. Specifically, the study will assess the effects of probiotics on vaccine-induced antibody responses and cellular immune responses, and explore whether probiotics may enhance or accelerate immunity and reduce vaccine-related adverse effects. A total of 140 participants are planned to be enrolled.
Detailed description
Large-scale clinical trials have demonstrated that COVID-19 vaccines effectively reduce the incidence of COVID-19, as well as the risk of severe disease and mortality. These protective effects are primarily mediated through vaccine-induced immune responses, including both humoral immunity (antibody production) and cellular immunity.
Probiotics are widely recognized for their potential health benefits and are commonly consumed in foods such as yogurt. Emerging evidence suggests that probiotic supplementation may enhance immune responses to vaccination, as demonstrated in studies involving influenza vaccines.
This study is designed to investigate whether oral probiotic supplementation can modulate the immune response to COVID-19 vaccination. The study will evaluate both antibody responses and cellular immune responses following vaccination, and assess whether probiotics can enhance or accelerate the development of vaccine-induced immunity. In addition, the study will explore whether probiotic supplementation may reduce vaccine-related adverse effects.
A total of 140 participants are planned to be enrolled in this study.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Probiotic Group | Experimental | Dietary Supplement: ProbioticsParticipants will receive oral probiotic capsules containing Lactobacillus spp. once daily for 4-5 weeks following COVID-19 vaccination. The intervention is administered to evaluate the immunomodulatory effects of probiotics on vaccine-induced humoral and cellular immune responses. |
| Placebo Group | Placebo comparator | Other: PlaceboParticipants will receive matching placebo capsules containing microcrystalline cellulose once daily for 4-5 weeks following COVID-19 vaccination. The placebo is identical in appearance, packaging, and administration schedule to the probiotic capsules. |
Who may qualify
- Ages
- 20 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Male or female subject ≥ 20 to ≤ 65 years of age at the time signing informed consent form.
- Body weight ≥50 kgs
- Must be scheduling to receive a BNT162b2 mRNA COVID-19 vaccine
- Being able to comply with the study protocol
- Being able to independently provide written informed consent
Key exclusion criteria (14 listed)
- Taking antibiotic at enrollment
- Taking immunomodulatory (e.g., steroid) or anti-histamine drugs
- Took pre- or probiotics within the past 30 days
- Being to expected to take other probiotic supplement during the study period
- Being expected to take antibiotic during the study period
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 |
|---|---|---|
| ProbioticsAlso: Lactobacillus spp., Probiotic supplement, Lactic acid bacteriaOral probiotic capsules containing Lactobacillus spp. administered once daily for 4-5 weeks following COVID-19 vaccination to evaluate immunomodulatory effects on vaccine-induced immune responses. | Dietary supplement | Probiotic Group |
| PlaceboMatching placebo capsules containing microcrystalline cellulose administered once daily for 4-5 weeks following COVID-19 vaccination. The placebo is identical in appearance, packaging, and schedule to the probiotic capsules. | Other | Placebo Group |
Primary outcome
SARS-CoV-2 spike protein-specific IgG antibody level
Time frame: Baseline (Day 0-7 before vaccination), Day 14 (±4 days), and Day 28 (±4 days) after first dose of BNT162b2 vaccination
Change in SARS-CoV-2 spike protein-specific IgG antibody levels following COVID-19 vaccination between probiotic and placebo groups.
SARS-CoV-2-specific T cell immune response at Day 14 after vaccination.
Time frame: Baseline and Day 14 (±4 days) after vaccination
Assessment of vaccine-induced cellular immune response measured by antigen-specific T cell activation between probiotic and placebo groups.
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 3 Jun 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 study testing Probiotics in people with COVID-19 and Immune Response, run by Grape King Bio Ltd. at 1 site in Taiwan.
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 14 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 3 Jun 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 Taiwan. 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.
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?
SARS-CoV-2 spike protein-specific IgG antibody level (time frame: Baseline (Day 0-7 before vaccination), Day 14 (±4 days), and Day 28 (±4 days) after first dose of BNT162b2 vaccination). The study lists 2 primary outcomes in all. 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 3 Jun 2026.