Drinking fermented milk containing Lactobacillus paracasei 431 (IMULUS™) improves immune response against H1N1 and cross-reactive H3N2 viruses after influenza vaccination: A pilot randomized triple-blinded placebo controlled trial

- Recent influenza vaccination showed low response against H3N2 viruses.
- Probiotic milk might improve vaccine response to H1N1 and cross-reactive H3N2.
- Drinking probiotic milk during vaccination may be advised for low immune subjects.

A randomized triple-blinded placebo controlled trial was conducted in healthy adults to evaluate the effects of daily consumption of fermented probiotic milk on immune response towards influenza virus type H1N1, H3N2 and Flu-B. Study and placebo groups (n = 30 each) consumed fermented milk containing 109Lactobacillus casei 431 and acidified milk respectively, and the vaccination was administered two weeks thereafter. The consumption continued for another four weeks. Anti-viral response was tested by Hemagglutination Inhibition (HAI) and ELISA assays. Results showed that study group had higher seroconversion rates for H1N1 and cross-reactive H3N2; higher HAI response (≥2-fold) rates for cross-reactive H3N2 virus; and increased ratios of geometric mean (study/placebo) for HAI titers and IgM of H1N1 and H3N2 viruses following the vaccination. These pilot results indicated that drinking fermented milk may be an approach to raise immune response against influenza A, especially for participants with low pre-existing immune.Clinical Trial Registry: ClinicalTrials.gov NCT02909842