A team of international scientists recently conducted a randomized clinical trial to assess the safety and efficacy profiles of a novel probiotic formulation in symptomatic coronavirus disease 2019 (COVID-19) patients.

The findings indicate that the probiotic formulation is highly effective in reducing symptom severity in COVID-19 patients without causing any adverse events. The study is currently available on the medRxiv* preprint server.

Study: Efficacy and safety of novel probiotic formulation in adult Covid19 outpatients: a randomized, placebo-controlled clinical trial. Image Credit: Orpheus FX / Shutterstock

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative pathogen of COVID-19, is an enveloped RNA virus belonging to the human beta-coronavirus family. Being a respiratory virus, SARS-CoV-2 primarily attacks the upper respiratory tract and subsequently propagates to the lower respiratory tract, causing mild to severe respiratory complications.

However, in a significant proportion of COVID-19 patients, the virus has been found to cause gastrointestinal infections manifested by nausea, vomiting, and diarrhea. This indicates the establishment of a gut–lung communication axis in COVID-19 patients. There is emerging evidence indicating that the gut microbial community can potentially modulate lung immune responses by priming gut immune cells and migrating them to the lung epithelium.       

Probiotics are live microorganisms with known health benefits. Some studies have suggested that probiotics could be beneficial in mild respiratory infections, such as the common cold. The most common probiotics are lactic acid bacteria, which are known to play a role in maintaining the gut microbiota.

In the current study, the scientists have evaluated the safety and efficacy of a novel probiotic formulation in COVID-19 patients. The formulation comprises three L. plantarum stains (KABP022, KABP023 and KABP033) and one P. acidilacti strain (KABP021).    

Study design

The study was conducted on 150 symptomatic patients with RT-PCR-confirmed SARS-CoV-2 infection. The participants were asked to consume one active probiotic capsule once daily for 30 consecutive days. A placebo-treated group of 150 COVID-19 patients was also included as experimental controls.

Important observations

Of a total of 300 patients (age range: 18 – 60 years), 293 completed the study. Three patients in the probiotic group and 4 patients in the placebo group could not complete the study.

Treatment efficacy

Compared to only 28% of patients in the placebo group, about 53% of patients in the probiotic group showed complete remission of infection 30 days after treatment initiation. Throughout the study, no hospitalization, intensive care unit admission, or death occurred in both groups.

The patients in the probiotic group reported faster recovery from symptoms, including fever, cough, headache, body ache, and breathlessness. Although consumption of acetaminophen was allowed during the study period, the participants in the probiotic group reported lower medicine intake than those in the placebo group.

A significantly lower nasopharyngeal viral load and significantly higher serum levels of IgG and IgM-specific anti-SARS-CoV-2 antibodies were observed in probiotic-treated patients compared to that in placebo-treated patients. A significant reduction in C-reactive protein and D-dimer levels was also observed in probiotic-treated patients compared to that in placebo-treated patients. In patients with lung complications, a significant improvement in radiographic findings was observed at day 15 and day 30 post probiotic treatment initiation.

Safety profile

Although none of the study participants showed any serious adverse complications, about 27% and 42% of participants in the probiotic and placebo group, respectively, exhibited treatment-emergent adverse events, including fever, cough, body ache, conjunctivitis, and difficulty swallowing. Since the incidence of adverse events was higher in the placebo group, the scientists believe that these events are most probably associated with COVID-19.

Study significance

The study describes the development of a probiotic formulation with three L. Plantarum stains (KABP022, KABP023 and KABP033) and one P. acidilacti strain (KABP021), which is well-tolerated in non-hospitalized patients with mild to moderate COVID-19. The formulation exhibits high efficiency in reducing viral load, subsiding lung pathologies, and reducing symptom duration. In addition, the formulation is capable of inducing anti-SARS-CoV-2 antibody levels in COVID-19 patients.

*Important Notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Written by

Dr. Sanchari Sinha Dutta

Dr. Sanchari Sinha Dutta is a science communicator who believes in spreading the power of science in every corner of the world. She has a Bachelor of Science (B.Sc.) degree and a Master's of Science (M.Sc.) in biology and human physiology. Following her Master's degree, Sanchari went on to study a Ph.D. in human physiology. She has authored more than 10 original research articles, all of which have been published in world renowned international journals.