Abstract
PurposeElderly people are particularly vulnerable to seasonal influenza. Therefore, vaccination is strongly recommended. However, the vaccine efficacy is lower in the elderly, owing to immunosenescence. The objective of the present study was to evaluate the ability of the probiotic strain Lactobacillus coryniformis K8 CECT5711 to enhance the immune response to the influenza vaccine in the elderly and to assess the effects on symptoms related to respiratory infections.MethodsA randomized, double-blind, placebo-controlled trial was conducted between November 2015 and April 2016. A total of 98 nursing home residents, more than 65 years of age were randomly assigned to receive L. coryniformis K8 CECT5711 (3 × 109 CFU/day) or a placebo for 2 weeks before influenza vaccination. The primary outcome was the percentage of seroconversion. The secondary outcomes were the incidence of influenza-like illness (ILI) and respiratory symptoms associated with respiratory infections during the 5-month follow-up period. The serum cytokine and immunoglobulin levels were also evaluated.ResultsThe percentage of responders to vaccination was higher in the probiotic group than in the control group (p = 0.036). L. coryniformis ingestion was associated with a significantly lower incidence of respiratory symptoms commonly associated with respiratory infections (p = 0.007) and lower consumption of analgesics (p = 0.008).ConclusionThe administration of L. coryniformis K8 CECT5711 to an elderly population increased the immune response against the influenza vaccine and decreased symptoms associated with respiratory infections. Probiotic administration may be a natural and safe strategy to improve the efficacy of vaccines and to protect against common respiratory infections in susceptible populations.
Highlights
The influenza A and B viruses are important human respiratory pathogens
Data from 84 volunteers were included for the analysis of immune responses, and data from 83 volunteers were included for the analysis of the incidence of symptoms of infection
The elderly population is more susceptible to infectious diseases, owing to loss of the ability of the immune system to function [3, 4]
Summary
The influenza A and B viruses are important human respiratory pathogens. Influenza occurs globally with an annual attack rate estimated at 5–10% in adults and 20–30% in children [1]. The elderly are vulnerable to seasonal influenza; approximately 90% of all influenza-related deaths occur among senior citizens [2]. Vaccination remains the most effective public health measure to decrease the effect of seasonal influenza and is strongly recommended for this population [1]. The efficacy of the vaccine is lower in the elderly, owing to the immunosenescence characteristic of this population [3, 4]. For this reason, the use of adjuvants has been proposed to enhance the immune response to the influenza vaccine in the elderly.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
