Results of a clinical trial of Lactobacillus Bulgaricus DWT1 in patients with COVID-19 presented at the 16th International Scientific Conference on Probiotics, Prebiotics, Gut Microbiota and Health – IPC2023, June 20-22, 2023 in Bratislava, Slovakia

You can see the entire presentation below the abstract


Application of Probiotic Formula, Containing Lactobacillus Bulgaricus DWT1 in Patients with COVID-19

Mariya Penevaa1, Ioannis Misopoulosb,Evgenia Barzashkac1, Tsvetan Lukanovc2, Tsetsa Doichinovac3, Anna Petkovad, Marieta Georgievae, Georgy Aleksandrova2, Pencho Tonchevc4

  • a – Medical Center “Eurozdrave-Bulgaria”, 7 Rusaliisky prohod str., Sofia, Bulgaria
  • b – Mika Nutri-Pharma Ltd., 18 Samuil str., Petrich, Bulgaria
  • c – University Hospital Pleven “Dr. Georgy Stranski”, 8a Georgy Kochev blvd., Pleven, Bulgaria
  • d – University General Hospital for Active Treatment St. Anna Sofia, 1 Dimitar Mollov str., Sofia, Bulgaria
  • e – Medical University of Varna “Prof. Dr. Paraskev Stoyanov”, 55 Marin Drinov str., Varna, Bulgaria

COVID-19 pandemic affected the world and claimed over 6 million victims. That’s why this clinical study shows significant information. Aim of the study is to evaluate the effect of probiotic formula, containing Lactobacillus bulgaricus DWT1, Streptococcus thermophilus DWT4, on cellular immunity in COVID-19 patients.

PCR tests, paraclinical blood tests, biochemical and immunological tests, X-ray, lung CT and medical consultations were performed. Statistics is done by IBM SPSS 23version.

The study is prospective, cohort, randomized, open-label. The subject are 78 inpatients treated for COVID-19 in 2020 randomly divided into two groups: group A – 47 patients taking probiotic, containing Lactobacillus bulgaricus DWT1 at daily dose 15-45g as part of complex therapy for COVID-19; group B – 31 patients receiving only standard therapy. Statistically the two groups didn`t differ in gender, age, incidence, type of concomitant diseases. Treatment in all cases included infusions, vitamins, antipyretics, corticosteroids, anticoagulants, H2-blockers, combination of antibiotics, oxygen. Treatment of group A patients included additional nutritional therapy with probiotic, containing Lactobacillus bulgaricus DWT1. Comparison of cellular immunity activity results in both groups showed statistically significant increase in NK-cells values, increase in cytotoxic T-lymphocytes marker and decrease/ normalization of T-helpers marker in group A patients. T-helpers produce cytokines which at high levels cause cytokine storm and death. Deaths in group B were patients admitted with high T-helpers, which increased extremely until the fatal outcome. Elevated T-helper levels in two patients from group A got normal during treatment. Hospital stay of group A patients is 4 days shorter compared to group B. Mortality in group A is 0%, in group B – 9,68%. In 2021, we conducted clinical observation of 8 pregnant women aged 25-38 years at 33-36 weeks of gestation, hospitalized for COVID-19. Lung CT showed pneumonia in all women. Treatment options during pregnancy are limited as many of medications for COVID-19 are contraindicated in pregnancy. All patients were treated with combination of two antibiotics and oxygen. Daily dose of anticoagulants depended on D-dimer values. All patients received probiotic formula, containing Lactobacillus bulgaricus DWT1 at daily dose of 30g, vitamins, pregnancy supplements. Only one patient received a small dose of corticosteroid for two days to improve fetal maturity. The general condition and paraclinical parameters of all improved on the 3rd-4th day. Inpatient treatment lasted up to 28 days. Delivery was performed by sectio caesarea. Women delivered live newborns with smooth uncomplicated postoperative period. Newborns are healthy, in good general condition with negative PCR tests.

The probiotic, containing Lactobacillus bulgaricus DWT1, modulates cellular immunity in COVID-19 patients – increases populations of NK-cells and cytotoxic T-lymphocytes and regulates T-helpers. Administration of this probiotic reduces COVID-19 death rate, shortens hospital stay and reduces the burden on healthcare system. This probiotic included in therapy successfully controls viral infection in pregnant women who give birth without complications to healthy live newborns not infected with COVID-19. The clinical observation results and the probiotic formula are subject of Bulgarian Patent №4294U and open new perspectives for application of Lactobacillus bulgaricus DWT1 as probiotic immunotherapy.


Immunity; Lactobacillus Bulgaricus DWT1; Pregnancy; Probiotic; SARS-CoV-2