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, Streptococcus thermophilus, Bifidobacterium breve, L. acidophilus, Bifidobacterium infantis, L. bulgaricus, and Fructooligosacharide. IRCT-20101020004976N6.
Ahanchian et al., 5/31/2021, Double Blind Randomized Controlled Trial, Iran, Middle East, peer-reviewed, 14 authors.
respiratory symptoms, 73.3% lower, RR 0.27, p = 0.35, treatment 1 of 29 (3.4%), control 4 of 31 (12.9%).
risk of COVID-19 case, 85.3% lower, RR 0.15, p = 0.24, treatment 0 of 29 (0.0%), control 3 of 31 (9.7%), continuity correction due to zero event (with reciprocal of the contrasting arm).
Effect extraction follows pre-specified rules
prioritizing more serious outcomes. For an individual study the most serious
outcome may have a smaller number of events and lower statistical signficance,
however this provides the strongest evidence for the most serious outcomes
when combining the results of many trials.