One hundred adults with confirmed (PCR or antigen test) symptomatic COVID-19 lasting upto 5 days will be screened for the study. When the subject meets enrollment criteria, he/she will be randomized to take an investigational product (probiotic, test dietary supplement, TDS), a mixture of lactobacilli and bifidobacteria or placebo 1 time a day before breakfast for 28 days after enrollment. During observation, the patient will keep Respiratory Illness Diary. Blood serum will be collected at baseline, day 0-5 (Nurse Visit 1), after 28-35 days (Nurse visit 2), and 6 months (Nurse visit 3) for evaluation of anti-SARS-CoV-2 antibodies to nucleocapsid and spike antigents. In 3 months, investigator/family physician will collect Post-COVID-19 Questionnaire
There is evidence that some types of probiotics play a role in alleviation of symptoms of acute respiratory tract infections and bursting immune response to respiratory and enteric viruses. Available data serves a rationale for the study exploring a role of nutritional support with probiotics in adult outpatients with COVID-19. Hypothesis of the study is that a proposed mixture of lactobacilli and bifidobacteria facilitate faster recovery from COVID-19 and enhance specific immune response to SARS-CoV-2 antigens.