Xenotransplantation People have dreamed of using animal organs and tissues to cure human disease for a very long time. Now researchers are starting to make that dream a reality. Here's how we got there. Hib Vaccine Vaccines are among the most powerful disease prevention tools we have. But they don't just pop out of thin air. Here is the story of a new vaccine that has stopped the child-killing bacterium Haemophilus influenzae in its tracks.