Infectious Disease
Double blind randomized controlled trial to evaluate the safety of Lactobacillus rhamnosus GG ATCC 53103 (LGG) vs. placebo in elderly subjects receiving live attenuated influenza vaccine (LAIV) Sam Gebeh* Sam Gebeh Gebeh Gebeh Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA
Background: Live attenuated influenza vaccine (LAIV) is recommended for healthy non-pregnant persons aged 2-49 years. LAIV has limited effect on vaccine response in the elderly (aged ≥65 years) who are at higher risk due to weakened immune system. Probiotics such as Lactobacillus rhamnosus GG (ATCC 53103) (LGG) may enhance immune response to mucosal vaccines but its effect as a vaccine adjuvant to LAIV is unknown. We conducted a Phase 1 trial of LGG vs. placebo in healthy elderly receiving LAIV, at the end of the 2011-2012 flu season, as it was not ethical to administer LAIV alone during the influenza season.
Objectives: (i) To assess the safety and tolerability of LGG vs. placebo in elderly subjects after LAIV; (ii) To measure anti-influenza systemic immune response (hemagglutinin inhibition (HAI) titers) and anti-influenza mucosal immune response (IgA titers) on Days 21, 28, 56 post LAIV.
Methods: Elderly subjects aged 65-80 years were randomized to 1×1010 CFU LGG or placebo twice daily for 28 days after receiving LAIV. We assessed subjects and got summary statistics of adverse events from baseline to Day 56. We measured serum HAI titers (H1N1, H3N2, B) and nasal wash influenza specific to total IgA titer ratios at baseline, day 21, 28, and 56 and used 2-sample t-test to compare changes in log geometric mean from baseline to day 28 in LGG vs. placebo group.
Results: Of all 30 subjects, 80% in each group reported treatment-related non-serious adverse events. There were no changes in the log geometric mean serum HAI titers over time in the LGG vs placebo group. Nasal IgA geometric mean fold rise at Day 28 were higher in the LGG group for all antigens, though modest differences between groups.
Conclusion: Administration of LGG with LAIV appears to be safe and well tolerated in elderly, with promising increases in all 3 strain specific nasal IgA fold rises 28 days post-vaccination.
Trial registration: NCT01545349
FDA IND: 14377
