The results of the inquiry and investigation that ensued are startling. It has been determined that the young people most likely to be affected are very active, athletic and high achievers or have a serious weight problem. A subset of the affected received the vaccination when they were at the pre-menstrual time of their cycle. What these three groups have in common is that estrogen, which we know protects the brain from stroke, is decreased leaving the brain more susceptible to damage of the capillaries and the neurotoxin aluminum.