THank you Dr. Rob and Dr. Shaw for your messages. I am glad to hear some positives about this vaccine. I got this for my 3 year old and plan to give it to my 5 month twins when they are the appropriate age. I was beginning to feel like I did a bad thing for my oldest daughter an That maybe I should not give it to the twins. THank you for the including the information about where it came from and how long it was tested for. Gratefully, Sandy Riese, RNC, IBCLC