Probiotics to Prevent Respiratory Infections in Nursing Homes: A Pilot Randomized Controlled Trial.

OBJECTIVES: To assess the feasibility of conducting a large clinical trial to evaluate the effectiveness of probiotics to reduce influenza and other respiratory virus infections in residents of long-term and chronic care facilities (LTCFs).

DESIGN: Randomized, double-blind, placebo-controlled pilot trial.

SETTING: Fourteen nursing homes in Hamilton and surrounding region, Ontario, Canada.

PARTICIPANTS: Nursing home residents aged 65 and older (N=209). Those who were taking immunosuppressives (steroids or other immunosuppressives) or had a hematological malignancy, structural heart disease, or gastroesophageal or intestinal injury and others at high risk of an endovascular infection were excluded.

INTERVENTION: Participants were randomized to receive study probiotics-2 capsules of Lactobacillus rhamnosus GG (estimated 10 billion colony forming units of L. rhamnosus GG per capsule) or placebo (calcium carbonate) daily for 6 months.

MEASUREMENTS: Laboratory-confirmed respiratory viral infections.

RESULTS: One hundred ninety-six individuals were included in the analysis: 100 in the probiotics group and 96 in the placebo group. Laboratory-confirmed respiratory viral infections were observed in 14 (15.0%) residents in the probiotic group and 21 (22.9%) in the placebo group (hazard ratio=0.65, 95% confidence interval=0.32-1.31).

CONCLUSION: A larger trial is warranted to determine whether probiotics reduce influenza and other respiratory virus infections in residents of LTCFs.