A few women in my family seem to have a terrible immune issue. We get sick extremely easily, and have had to go to the hospital from flu vaccines. My sister and cousin have both had mono for several years and my sister had HSP and scarlet fever. I used to vomit every morning before I went to school with no explanation found. My cousin develops allergies overnight. Also, my sister just went to a doctor for tests and they said that most of her vaccines have not been effective. What could this be?