Stanford Bio-X Frontiers in Interdisciplinary Biosciences Seminar
Speaker: Christine Stabell-Benn, Bandim Health Project, Statens Serum Institut
Seminar Title: "Time to change a paradigm: non-specific effects of vaccines"
Hosted by: Dr. Annelise Barron, Associate Professor of Bioengineering, Stanford University
Unknown to most people, vaccines were never tested for their effects on overall health before being introduced. Everybody was so certain that vaccines only affect the target infection that it did not seem necessary. Our population-based epidemiological studies in one of the world’s poorest countries, Guinea-Bissau, have now revealed that this assumption is too simplistic. In this setting, with a very high infectious disease mortality, it became clear that vaccines not only protect against the target infection, they also affect the susceptibility to other infections. We have called these effects the “non-specific effects” of vaccines. Live vaccines (e.g. against measles, polio, tuberculosis and smallpox) increase the resistance towards many other infections. Worryingly, non-live vaccines (e.g. against diphtheria, tetanus, pertussis and hepatitis B) increase the susceptibility to other infections and the overall effect may be negative; this, however, may be circumvented by providing live vaccines afterwards. Immunological studies are now providing a biological mechanism by showing that vaccines modulate the innate immune system. These findings challenge our understanding of vaccines and the immune system. The implications are far-reaching: hundreds of thousands of lives could be saved every year in low-income countries and morbidity and health expenditure could be reduced significantly in high-income countries, simply by using the existing vaccines smarter.