In the present study, the investigators want to investigate whether prior BCG-vaccination improves the efficacy of influenza ("the flu") vaccination in young and/or old healthy volunteers and consequently could protect against influenza virus infection.
Influenza virus infection leads to millions of cases of severe illnesses worldwide and up to an estimated 500.000 deaths annually. The potential for the sudden emergence of pandemic influenza strains represents an incessant threat on even a larger scale. seasonal influenza vaccination is the backbone of influenza management. However, antibodies generated by vaccination, most often do not effectively neutralize emergent strains due to the high mutation rate of the influenza viral genome. In addition, although vaccination is effective in up to 85% of healthy adults, only 40-60% of the elderly are able to mount an protective antibody response due to an agerelated decline in immune function (so-called immunoscenescence). As a result, the protective effects of influenza vaccination are limited, and strategies to improve host immune defenses against influenza virus infection per se, and following influenza vaccination, are highly warranted. It is suggested that prior vaccination with Bacille Calmette-Guérin (BCG) could enhance resistance to other infectious diseases in addition to protection to tuberculosis (TBC) and, in mice, protection of prior BCGvaccination against influenza infection was demonstrated long ago. However, only recently substantial evidence for these nonspecific beneficial effects of BCG-vaccination in humans has been provided by several randomized clinical trials. Considering these potentiating effects of BCG-vaccination, it could be a viable strategy to improve efficacy of influenza vaccination, and/or enhance immune defenses against influenza virus infection per se. If so, this would have an enormous impact on clinical practice.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
40
Radboud University Nijmegen Medical Centre
Nijmegen, Gelderland, Netherlands
Difference in influenza antibody titres between BCG-vaccinated subjects and subjects in the control group
Time frame: Day 14, day 21, day 28, day 42 (±2 days)
Difference in Thrombocyte function between BCG-vaccinated subjects and subjects in the control group
Time frame: Day 0, day 14, day 21, day 28, day 42 (±2 days)
Proportion of participants in each group who achieved seroprotection (defined by antibody titre ≥1:40).
Time frame: day 21, day 28, day 42 (±2 days)
Proportion of participants in each group who achieved seroconversion (defined by a ≥4-fold rise in antibody titre).
Time frame: day 21, day 28, day 42 (±2 days)
IFN-gamma/IL-10 production of leukocytes ex vivo stimulated with inactivated/live influenza virus (0.1ug HA/ml).
Time frame: Day 0, day 14, day 28, day 42 (±2 days)
Production of Type 1 IFNs, IL-17 and IL-22 by leukocytes ex vivo stimulated with inactivated/live influenza virus (0.1ug HA/ml).
Time frame: Day 0, day 14, day 28, day 42 (±2 days)
Production of other inflammatory mediators (including TNFα, IL-1β, IFN-gamma, IL-10, IL-17, IL-22) by leukocytes ex vivo stimulated with different not-related stimuli (including m. tuberculosis, s. aureus, c. albicans, and inactivated influenza).
Time frame: Day 0, day 21, day 28, day 42 (±2 days)
Inflammatory transcriptional pathways (by use of qPCR/microarrays) .
Time frame: Day 0, day 14, day 28, day 42 (±2 days)
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Granzyme B production of leukocytes ex vivo stimulated with inactivated/live influenza virus (0.1ug HA/ml).
Time frame: Day 0, day 14, day 28, day 42 (±2 days)