Effect of live and inactivated Lactobacillus rhamnosus GG on experimentally induced rhinovirus colds: randomised, double blind, placebo-controlled pilot trial.

The aim of this work was to investigate the usability of an experimental rhinovirus model in probiotic trials aiming to assess effectiveness in viral infections, and to provide preliminary data of live and inactivated probiotic Lactobacillus rhamnosus GG for larger-scale trials utilising the model. 59 subjects were randomised to receive 100 ml of fruit juice supplemented with 10(9) cfu of live or heat-inactivated (by spray-drying) L. rhamnosus GG or control juice daily for six weeks. After three weeks subjects were intranasally inoculated with experimental rhinovirus. Infection rate (at least one positive culture for challenge virus on five days following inoculation or at least four-fold rise in antibody response to challenge virus) was 14/19 in the group receiving live probiotic strain and 18/20 both in the group receiving heat-inactivated probiotic strain and in the control group (P=0.36). The occurrence and severity of cold symptoms on the five days following the inoculation was lowest in the group receiving live probiotic strain (P=0.45). This trial was the first one dedicated to the investigation of the effect of probiotics using the experimental rhinovirus model. The model showed potential for demonstration of efficacy of probiotics in controlled respiratory viral infections. Occurrence and severity of cold symptoms and number of subjects with rhinovirus infection was lowest in the group receiving live L. rhamnosus GG, but differences were not statistically significant. Further large-scale studies are needed to demonstrate the efficacy of L. rhamnosus GG in respiratory infections.

Milk containing probiotic Lactobacillus rhamnosus GG and respiratory illness in children: a randomized, double-blind, placebo-controlled trial.

BACKGROUND/OBJECTIVES: To determine whether long-term daily consumption of milk containing probiotic Lactobacillus rhamnosus GG (GG) decreases respiratory illness in children. SUBJECTS/METHODS: A randomized, double-blind, placebo-controlled trial was conducted with 523 children aged 2-6 years attending day care centers in Finland. Subjects received either normal milk or the same milk with GG on three daily meals for 28 weeks. Daily recording of children' symptoms was done by parents. Primary outcome data from 501 subjects were available for analysis, and data from 128 subjects were analyzed as completed cases in terms of recovery of GG in fecal samples. RESULTS: Number of days with at least one respiratory symptom in all subjects was 5.03/month (95% confidence interval (CI): 4.92-5.15) in the GG group and 5.17/month (95% CI: 5.05-5.29) in the placebo group incidence rate ratio (IRR) 0.97; 95% CI: 0.94-1.00; P=0.098). In the completed cases, the figures were 4.71 days/month (95% CI: 4.52-4.90) in the GG group and 5.67 days/month (95% CI: 5.40-5.94) in the placebo group (IRR 0.83; 95% CI: 0.78-0.88; P<0.001). CONCLUSIONS: Consumption of GG reduced the occurrence of respiratory illness in children attending day care centers in the completed cases subgroup, but not in the total population. Thus, future clinical trials are warranted to clarify the association between fecal recovery of a probiotic and the symptom prevalence.