1. Introduction:
Severe Acute Respiratory Coronavirus 2 (SARS-CoV-2), a newly identified
coronavirus with size of 60–140 nm similar to SARS-CoV (approximately
80% similar), caused the most severe pandemic disorder of
21st century called COVID-19 1,2.
SARS-CoV-2 attaches to Angiotensin Converting Enzyme 2 (ACE2) receptor
with 10–20 folds higher affinity than SARS-CoV 3.
Today, massive antibiotic therapy is considered for some COVID-19
patients that result in more susceptibility to subsequent infections4; one of the most irritant complications is
antibiotic-associated diarrhea 5. In this situation,
probiotics may be a reasonable choice; they were defined as “Live
microorganisms which when administered in adequate amounts confer a
health benefit to the host” 6. on the other hand,
Probiotics have shown useful effects on treatment and prevention of
viral infections 7 due to the proven immunomodulatory
activity and ability to stimulate interferon production; gut–lung axis
explains the possible relations between respiratory disorders and gut
microbiome 8.
Recently, some COVID-19 patients showed microbial dysbiosis with
decreased Lactobacillus and Bifidobacterium9. Several different probiotics, includingLactobacillus acidophilus, Bifidobacterium andSaccharomyces boulardii , along with minerals & vitamins were
given to a COVID-19 case; this type of nutritional support lowered the
complication of massive antibiotic therapy 10. As
well, COVID-19-like symptoms disappeared after two days administration
of oral probiotic in a 9 years-old boy 11. Results of
a case series consist of 62 SARS-CoV2 infected patients in Zhejiang
province were interesting; probiotics were administered as adjunct12. Other reports showed significant effect of
probiotics; Compared to patients with non-severe disease, patients with
severe disease had significantly more frequency to receive probiotics
tablets (87.5% vs 40.4%, p=0.037) 13. Results from
another research suggested concurrent use of probiotics in COVID-19
patients to decrease the risk for Candida albicans (caused by
prophylaxis with azithromycin) 14.
Up to April 2020, two clinical trials have been registered regarding the
probiotics supplementation in COVID-19 patients 15,
however, more information is needed for designing research protocols. We
tried to summarize the possible relationships between probiotics and
viral infections especially SARS-CoV-2-related literature in this
systematic review.