Table 1.
Clinical trials conducted for probiotics against coronavirus disease 2019 registered at ClinicalTrials.gov posted from May 2020 to December 2021
| Location | Official Title | Dosage form | Probiotic Strain | Number of Participants |
|---|---|---|---|---|
| Austria | Synbiotic Therapy of Gastrointestinal Symptoms During Covid-19 Infection: A Randomized, Double-blind, Placebo-Controlled, Telemedicine Study (SynCov Study) | Oral powder containing ten strains 5*109 CFU/sachet | Bifidobacterium bifidum, Bifidobacterium lactis, Enterococcus faecium, Lactobacillus acidophilus, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus and Ligilactobacillus salivarius | 30 |
| Canada | Evaluation of the Efficacy of Probiotics to Reduce the Duration and Symptoms of COVID-19 (PROVID-19 Study): a Randomized, Double-blind, Controlled Trial | Oral capsule containing 2 strains 10*109 CFU/ capsule | Not specified | 17 |
| Canada | Evaluation of the Efficacy of Probiotics Taken During the Acute Phase of COVID-19 to Reduce the Occurrence of Long COVID | Oral capsule containing 2 strains 10*109 CFU/capsule | Not specified | 618 |
| Canada | Randomized Single Blinded Clinical Study of Efficacy of Intranasal Probiotic Treatment to Reduce Severity of Symptoms in COVID19 Infection | Nasal irrigations with probiotic 2.4 *109 CFU/dose | Lactococcus lactis W136 | 23 |
| Hong Kong | A Randomized-controlled Trial of an Oral Microbiome Immunity Formula in Reducing Development of Long-term Co-morbidities in Recovered COVID-19 Patients | Oral powder containing three strains 10*109 CFU/sachet | 3 Bifidobacterial strain | 280 |
| Mexico | Efficacy and Safety of Lactobacillus plantarum and Pediococcus acidilactici as Co-adjuvant Therapy for Reducing the Risk of Severe Disease in Adults With SARS-CoV-2 and Its Modulation of the Fecal Microbiota: A Randomized Clinical Trial | Oral capsule containing two strains 10*109 CFU/capsule | Three Lactobacillus plantarum strains and Pediococcus acidilactici | 300 |
| Pakistan | Study to Investigate the Treatment Effect of Probiotic Streptococcus salivarius K12 in Hospitalised Patients (Non-ICU) With COVID-19 | Oral tablet containing two strains 1*109 CFU/tablet | Streptococcus salivarius K12 | 50 |
| Russia | Efficacy of Probiotics (Lactobacillus rhamnosus, Bifidobacterium bifidum, Bifidobacterium longum subsp. infantis, and Bifidobacterium longum) in the Treatment of Hospitalized Patients with Novel | Oral capsule containing 4 strains 4*109 CFU/capsule | Lactobacillus rhamnosus, Bifidobacterium bifidum, Bifidobacterium longum subsp. infantis and Bifidobacterium longum | 200 |
| Spain | The Intestinal Microbiota as a Therapeutic Target in Hospitalized Patients With COVID-19 Infection | Oral tablet containing 2 strains 1*109 CFU/tablet | Not specified | 41 |
| Spain | Administration of Ligilactobacillus salivarius MP101 in an Elderly Nursing Home During the COVID Pandemics |
Fermented milk containing 10*109 CFU/dose |
Ligilactobacillus salivarius MP101 | 25 |
| Spain | Changes in Viral Load in Patients With COVID-19 Disease After Dietary Supplementation with Probiotics: A Randomized Clinical Trial | Oral powder containing three strains plus vitamin D, zinc and selenium | Bifidobacterium longum, Bifidobacterium animalis subsp. lactis and Lactobacillus rhamnosus | 96 |
| Spain | Multicenter, Randomized, Double-blind Parallel Group Pilot Study to Evaluate the Effect of the Consumption of a Lactobacillus strain on the Incidence of Covid-19 in the Elderly | Oral capsule containing strain 3*109 CFU/capsule | A Lactobacillus strain | 201 |
| Spain | The Effect of Consumption of Lactobacillus coryniformis K8 on Healthcare Personnel Exposed to COVID-19 | Oral capsule containing a strain 3*109 CFU/capsule | Lactobacillus coryniformis K8 | 314 |
| Sweden | Exploratory Study on the Effects of Probiotic Supplementation on SARS-CoV-2 Antibody Response in Healthy Adults | Oral capsule containing 10*108 probiotics + 10 ug vitamin D3 | Lactobacillus reuteri | 161 |
| Ukraine | Role of Nutritional Support with Probiotics in Adult Outpatients with Symptomatic | Oral capsule containing two strains 5*109 CFU/capsule | A mixture of Bifidobacteria and Lactobacillus | 300 |
| United states | A randomized trial of the effect of Lactobacillus on the microbiome of household contacts | Oral capsule containing a strain 1*109 CFU/capsule | Lactobacillus rhamnosus GG | 182 |