Effects of Lactobacillus coryniformis K8 CECT5711 on the immune response to influenza vaccination and the assessment of common respiratory symptoms in elderly subjects: a randomized controlled trial

Purpose Elderly 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.