https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2870374/ Note this study is from 2006. Based on models so don't know how much faith I would put in it, but still............ "We show that repeated vaccination at a young age substantially increases the risk of influenza in older age, by a factor ranging between 1·2 (vaccination after 50 years) to 2·4 (vaccination from birth). These findings have important implications for influenza vaccination policies." This "health" stuff interventions is not without risk itself. John |