Conv. Plasma
Nigella Sativa
Peg.. Lambda
Vitamin A
Vitamin C
Vitamin D

Home   COVID-19 treatment studies for Probiotics  COVID-19 treatment studies for Probiotics  C19 studies: Probiotics  Probiotics   Select treatmentSelect treatmentTreatmentsTreatments
Antiandrogens (meta) Lactoferrin (meta)
Aspirin (meta) Melatonin (meta)
Bamlaniv../e.. (meta) Metformin (meta)
Bebtelovimab (meta) Molnupiravir (meta)
Bromhexine (meta) N-acetylcys.. (meta)
Budesonide (meta) Nigella Sativa (meta)
Cannabidiol (meta) Nitazoxanide (meta)
Casirivimab/i.. (meta) Paxlovid (meta)
Colchicine (meta) Peg.. Lambda (meta)
Conv. Plasma (meta) Povidone-Iod.. (meta)
Curcumin (meta) Probiotics (meta)
Diet (meta) Proxalutamide (meta)
Ensitrelvir (meta) Quercetin (meta)
Ensovibep (meta) Remdesivir (meta)
Exercise (meta) Sleep (meta)
Famotidine (meta) Sotrovimab (meta)
Favipiravir (meta) Tixagev../c.. (meta)
Fluvoxamine (meta) Vitamin A (meta)
Hydroxychlor.. (meta) Vitamin C (meta)
Iota-carragee.. (meta) Vitamin D (meta)
Ivermectin (meta) Zinc (meta)

Other Treatments Global Adoption
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Haran (RCT) 67% 0.33 [0.01-8.16] death 0/174 1/176 Improvement, RR [CI] Treatment Control Gutiérre.. (DB RCT) 35% 0.65 [0.53-0.80] no recov. 69/147 105/146 Veterini 29% 0.71 [0.41-1.22] viral time 15 (n) 15 (n) Tau​2 = 0.00, I​2 = 0.0%, p < 0.0001 Early treatment 34% 0.66 [0.55-0.79] 69/336 106/337 34% improvement d'Ettorre 87% 0.13 [0.01-2.33] death 0/28 4/42 Improvement, RR [CI] Treatment Control Ceccarelli 64% 0.36 [0.18-0.68] death 10/88 34/112 Shah (RCT) 11% 0.89 [0.75-1.06] recov. time 30 (n) 30 (n) CT​1 Li -12% 1.12 [0.74-1.69] no disch. 30/123 41/188 Zhang 14% 0.86 [0.77-0.96] hosp. time 150 (n) 150 (n) Ceccarelli 70% 0.30 [0.01-7.02] death 0/40 1/29 Ivashkin (RCT) -2% 1.02 [0.26-3.97] death 4/99 4/101 Zhang 65% 0.35 [0.02-8.30] ventilation 0/25 1/30 Tau​2 = 0.02, I​2 = 37.4%, p = 0.067 Late treatment 16% 0.84 [0.70-1.01] 44/583 85/682 16% improvement Louca 8% 0.92 [0.85-0.99] cases Improvement, RR [CI] Treatment Control Di Pierro (RCT) 98% 0.02 [0.00-0.33] cases 0/64 24/64 Holt 30% 0.70 [0.45-1.10] cases 20/909 426/14,318 Ahanchian (DB RCT) 73% 0.27 [0.03-2.25] symp. case 1/29 4/31 Wischme.. (DB RCT) 33% 0.67 [0.38-1.17] m/s case 16/91 24/91 Tau​2 = 0.11, I​2 = 63.4%, p = 0.085 Prophylaxis 31% 0.69 [0.45-1.05] 37/1,093 478/14,504 31% improvement All studies 21% 0.79 [0.69-0.90] 150/2,012 669/15,523 21% improvement 16 probiotics COVID-19 studies Jul 2022 Tau​2 = 0.02, I​2 = 52.3%, p = 0.00043 Effect extraction pre-specified(most serious outcome) 1 CT: study uses combined treatment Favors probiotics Favors control
Probiotics COVID-19 studies. The immune effects of probiotics are strain-specific and studies use different strains. Recent:
Probiotics have been officially adopted for early treatment in 1 country. Submit updates/corrections.
Mar 2
Late Zhang et al., Journal of Gastroenterology and Hepatology, doi:10.1111/jgh.15796
ventilation, ↓64.7%, p=1.00
Gut microbiota‐derived synbiotic formula (SIM01) as a novel adjuvant therapy for COVID‐19: An open‐label pilot study
Details   Pilot study of probiotic SIM01 with 25 consecutive COVID-19 patients in Hong Kong and 30 control patients treated by a different team during the same time period, showing improved antibody formation, reduced viral load and pro-inflammator..
Jan 12
Late Santinelli et al., Frontiers in Nutrition, doi:10.3389/fnut.2021.756177
no recov., ↓54.3%, p<0.0001
Oral Bacteriotherapy Reduces the Occurrence of Chronic Fatigue in COVID-19 Patients
Details   Retrospective 58 hospitalized patients, 24 receiving probiotics during hospitalization, showing significantly lower fatigue six months post discharge with treatment.
Jan 5
PrEPPEP Wischmeyer et al., medRxiv, doi:10.1101/2022.01.04.21268275 (Preprint)
m/s case, ↓33.3%, p=0.15
Daily Lactobacillus Probiotic versus Placebo in COVID-19-Exposed Household Contacts (PROTECT-EHC): A Randomized Clinical Trial
Details   RCT 182 COVID-19 exposed patients, 91 treated with daily probiotic Lactobacillus rhamnosus GG starting a median of 3 days from exposure, showing lower symptomatic COVID-19 with treatment. There were no hospitalizations or deaths. PROTECT-..
Dec 31
Late Wang et al., Annals of Palliative Medicine, doi:10.21037/apm-21-3373 The efficacy of probiotics in patients with severe COVID-19
Details   Retrospective 156 COVID-19 patients in China, showing that diarrhea was significantly more common in severe/critical cases, and for severe/critical patients experiencing diarrhea, the duration of diarrhea was shorter with probiotic treatm..
Nov 25
Late Bozkurt et al., International Journal of Immunopathology and Pharmacology, doi:10.1177/20587384211059677 Oral booster probiotic bifidobacteria in SARS-COV-2 patients
Details   Small retrospective 44 hospitalized patients in Turkey, showing improved outcomes with probiotic bifidobacterium, however minimal group details are provided (for example, the age of the control patients is unknown), and no adjustments wer..
Oct 25
Late Leal-Martínez et al., International Journal of Environmental Research and Public Health, doi:10.3390/ijerph19031172 (preprint 10/25/2021)
death, ↓85.7%, p=0.03
Effect of a Nutritional Support System to Increase Survival and Reduce Mortality in Patients with COVID-19 in Stage III and Comorbidities: A Blinded Randomized Controlled Clinical Trial
Details   80 patient RCT with 40 patients treated with a comprehensive regimen of nutritional support, showing significantly lower mortality with treatment. Treatment contained cholecalciferol, vitamin C, zinc, spirulina maxima, folic acid, glutami..
Oct 13
Late Ivashkin et al., Probiotics Antimicrob Proteins, doi:10.1007/s12602-021-09858-5
death, ↑2.0%, p=1.00
Efficacy of a Probiotic Consisting of Lacticaseibacillus rhamnosus PDV 1705, Bifidobacterium bifidum PDV 0903, Bifidobacterium longum subsp. infantis PDV 1911, and Bifidobacterium longum subsp. longum PDV 2301 in the Treatment of Hospitalized Patients with COVID-19: a Randomized Controlled Trial
Details   RCT 200 patients, 99 treated with a probiotic (Lacticaseibacillus rhamnosus PDV 1705, Bifidobacterium bifidum PDV 0903, Bifidobacterium longum subsp. infantis PDV 1911, and Bifidobacterium longum subsp. longum PDV 2301). There was no sign..
Aug 30
Late Rathi et al., Medicines, doi:10.3390/medicines8090047
no recov., ↓89.4%, p<0.0001
A Randomized Controlled Trial of the Efficacy of Systemic Enzymes and Probiotics in the Resolution of Post-COVID Fatigue
Details   RCT 200 long-COVID patients in India, 100 treated with ImmunoSEB and ProbioSEB CSC3, showing improved recovery of post-COVID-19 fatigue with treatment. CTRI/2021/05/033576.
Aug 23
Late Ceccarelli et al., Nutrients, doi:10.3390/nu13082898
death, ↓70.4%, p=0.42
Oxygen Sparing Effect of Bacteriotherapy in COVID-19
Details   Prospective analysis of 69 severe COVID-19 patients requiring non-invasive oxygen therapy, 40 treated with probiotic formulation SLAB51, showing lower oxygen requirements and higher blood levels of pO2, O2Hb and SaO2 with treatment. Autho..
Aug 4
Late Zhang et al., Therapeutic Advances in Gastroenterology, doi:10.1177/17562848211035670
hosp. time, ↓13.6%, p=0.009
Probiotics use is associated with improved clinical outcomes among hospitalized patients with COVID-19
Details   Retrospective 375 patients in China, 179 treated with probiotics (Bifidobacterium, Lactobacillus, and Enterococcus), showing improved clinical outcomes with treatment.
Jun 30
Early Veterini et al., Indian Journal of Forensic Medicine & Toxicology, 15:2
viral- time, ↓29.0%, p=0.22
Probiotics Intake as Adjunct Therapy for Infected Health-Care with SARS COV-2
Details   Small case control analysis with 15 probiotics patients and 15 contol patients, showing no significant differences. PCR tests were only done weekly. Dosage is unknown. 115/LOE/301.4.2/IX/2020.
Jun 24
PrEPPEP Wang et al., Front. Bioeng. Biotechnol., doi:10.3389/fbioe.2021.646184 Oropharyngeal Probiotic ENT-K12 Prevents Respiratory Tract Infections Among Frontline Medical Staff Fighting Against COVID-19: A Pilot Study
Details   Prophylaxis RCT in China with 98 healthcare workes in close contact with COVID-19 patients treated with Bactoblis oropharyngeal probiotic containing S. thermophilus ENT-K12, and 95 control patients, showing lower incidence of respiratory ..
Jun 1
Late Meskina et al., Therapeutic Archive, doi:10.26442/00403660.2021.04.200835 Efficiency of application of sorbed probiotics in complex therapy of pneumonia caused by SARS-CoV-2
Details   RCT 100 pneumonia patients in Russia, showing faster symptom resolution with probiotic treatment (B. bifidum 1).
May 31
PrEPPEP Ahanchian et al., Open Journal of Nursing, doi:10.4236/ojn.2021.115025
symp. case, ↓73.3%, p=0.35
Synbiotic for Prevention of SARS-Cov2 Infection in High Risk Hospital Staffs: A Randomized Controlled Trial
Details   Small RCT 60 healthcare workers in Iran, showing lower cases with treatment but without statistical significance. Once daily oral synbiotic capsule (Lactocare®) containing 1 billion CFU L. (Lactobacillus) casei, L. rhamnosus, Streptococcu..
May 24
Early Gutiérrez-Castrellón et al., Gut Microbes, doi:10.1080/19490976.2021.2018899 (preprint 5/24/2021)
no recov., ↓34.7%, p<0.0001
Probiotic improves symptomatic and viral clearance in Covid19 outpatients: a randomized, quadruple-blinded, placebo-controlled trial
Details   RCT 293 outpatients in Mexico, 147 treated with a probiotic composed of three L. plantarum strains (KABP022, KABP023 and KABP033) and one P. acidilacti strain (KABP021), showing improved recovery with treatment. There were no hospitalizat..
Apr 7
Review Di Pierro, F., Minerva Medica, doi:10.23736/S0026-4806.20.06570-2 (Review)
A possible probiotic (S. salivarius K12) approach to improve oral and lung microbiotas and raise defenses against SARS-CoV-2
Details   Review of the potential use of S. salivarius K12 for COVID-19. Author notes that strain K12 of Streptococcus salivarius may reduce occurrence of viral upper respiratory tract infections, possibly due to its ability to stimulate IFN-γ rele..
Mar 30
PrEPPEP Holt et al., Thorax, doi:10.1136/thoraxjnl-2021-217487
cases, ↓30.4%, p=0.11
Risk factors for developing COVID-19: a population-based longitudinal study (COVIDENCE UK)
Details   Prospective survey-based study with 15,227 people in the UK, showing lower risk of COVID-19 cases with vitamin A, vitamin D, zinc, selenium, probiotics, and inhaled corticosteroids; and higher risk with metformin and vitamin C. Statistica..
Mar 29
Early Haran et al., medRxiv, doi:10.1101/2021.03.26.21254422 (Preprint)
death, ↓66.5%, p=1.00
Targeting the Microbiome With KB109 in Outpatients with Mild to Moderate COVID-19 Reduced Medically Attended Acute Care Visits and Improved Symptom Duration in Patients With Comorbidities
Details   RCT 350 COVID+ outpatients in the USA, 174 treated with prebiotic KB109 (a microbiome metabolic therapy candidate), showing lower combined hospitalization, ER, and urgent care visits with treatment. NCT04414124.
Mar 19
Review Kurian et al., Archives of Medical Research, doi:10.1016/j.arcmed.2021.03.002 (Review)
Probiotics in Prevention and Treatment of COVID-19: Current Perspective and Future Prospects
Details   Review of probiotics role in regulating the immune system and use in viral infections, and studies on the association of microbiota with COVID-19 patients. Authors suggest that probiotics supplementation could reduce COVID-19 morbidity an..
Mar 12
PrEPPEP Di Pierro et al., Minerva Medica, doi:10.23736/S0026-4806.21.07487-5
cases, ↓98.0%, p<0.0001
The administration of S. salivarius K12 to children may reduce the rate of SARS-CoV-2 infection
Details   Interim report on an RCT for prophylactic treatment with S. salivarius K12, showing significantly lower cases with treatment. Only patients with symptoms or known positive contacts were tested. Trial identification/registration details ar..
Mar 5
Late Li et al., International Immunopharmacology, doi:10.1016/j.intimp.2021.107531
no disch., ↑11.8%, p=0.68
The role of probiotics in coronavirus disease-19 infection in Wuhan: A retrospective study of 311 severe patients
Details   Retrospective 311 severe condition hospitalized patients in China, 123 treated with probiotics, showing slower viral clearance and recovery with treatment. Authors note that probiotics were able to moderate immunity and decrease the incid..
Feb 13
Review Singh et al., Nutrition Research, doi:10.1016/j.nutres.2020.12.014 (Review)
Probiotics: A potential immunomodulator in COVID-19 infection management
Details   Review of studies supporting the use of probiotics for respiratory infections and identification of microbial strains potentially beneficial for COVID-19.
Feb 2
Late Shah et al., Advances in Clinical Toxicology, doi:10.23880/act-16000204
recov. time, ↓10.8%, p=0.19
Potential of the Combination of a Systemic Enzyme Complex and Probiotics administration to Combat COVID-19: A Randomized Open Label Prospective Analysis
Details   Small RCT 60 patients in India, 30 treated with ImmunoSEB and ProbioSEB CSC3, showing faster recovery with treatment. CTRI/2020/09/027685, CTRI/2020/08/027168.
Jan 11
Late Ceccarelli et al., Frontiers in Medicine, doi:10.3389/fnut.2020.613928
death, ↓64.2%, p=0.003
Oral Bacteriotherapy in Patients With COVID-19: A Retrospective Cohort Study
Details   Retrospective 200 severe condition hospitalized patients in Italy, 88 treated with probiotic Sivomixx, showing lower mortality with treatment.
Dec 15
Review Stavropoulou et al., Frontiers in Nutrition, doi:10.3389/fnut.2020.614986 (Review)
Probiotics as a Weapon in the Fight Against COVID-19
Details   Review of the potential benefits of probiotics for COVID-19.
Nov 30
PrEPPEP Louca et al., BMJ Nutrition, Prevention & Health, doi:10.1136/bmjnph-2021-000250 (preprint 11/30/20)
cases, ↓8.5%, p=0.03
Modest effects of dietary supplements during the COVID-19 pandemic: insights from 445 850 users of the COVID-19 Symptom Study app
Details   Survey analysis of dietary supplements showing probiotic usage associated with lower incidence of COVID-19. These results are for PCR+ cases only, they do not reflect potential benefits for reducing the severity of cases. A number of bias..
Oct 5
Review Olaimat et al., npj Science of Food, doi:10.1038/s41538-020-00078-9 (Review)
The potential application of probiotics and prebiotics for the prevention and treatment of COVID-19
Details   Review of the immune benefits of probiotics and clinical studies for the preventation and treatment of respiratory infections, recommending trials of probiotics for COVID-19.
Jul 7
Late d'Ettorre et al., Frontiers in Medicine, doi:10.3389/fmed.2020.00389
death, ↓87.0%, p=0.14
Challenges in the Management of SARS-CoV2 Infection: The Role of Oral Bacteriotherapy as Complementary Therapeutic Strategy to Avoid the Progression of COVID-19
Details   Retrospective 70 hospitalized patients in Italy, 28 treated with probiotic Sivomixx, showing lower risk of respiratory failure and faster recovery with treatment.
May 8
Review Baud et al., Frontiers in Public Health, doi:10.3389/fpubh.2020.00186 (Review)
Using Probiotics to Flatten the Curve of Coronavirus Disease COVID-2019 Pandemic
Details   Review of data supporting the use of probiotics for COVID-19 and mechanisms of action.
Meta Hao et al., Cochrane Database of Systematic Reviews, doi:10.1002/14651858.CD006895.pub3 (Preprint) (meta analysis)
Probiotics for preventing acute upper respiratory tract infections
Details   Meta analysis of 12 RCTs with 3,720 patients showing probiotics reduced acute upper respiratory tract infections.
Please send us corrections, updates, or comments. Vaccines and treatments are both valuable and complementary. All practical, effective, and safe means should be used. No treatment, vaccine, or intervention is 100% available and effective for all current and future variants. Denying the efficacy of any method increases mortality, morbidity, collateral damage, and the risk of endemic status. We do not provide medical advice. Before taking any medication, consult a qualified physician who can provide personalized advice and details of risks and benefits based on your medical history and situation. FLCCC and WCH provide treatment protocols.
  or use drag and drop   
Thanks for your feedback! Please search before submitting papers and note that studies are listed under the date they were first available, which may be the date of an earlier preprint.