The head of an international vaccine group says that misunderstandings and false information about vaccines are spreading on the internet and should be stopped. Seth Berkley of Gavi, the Vaccine Alliance, spoke Tuesday to a gathering in Geneva, Switzerland, where the World Health Organization is meeting. Berkley said that false information “kills people.” He noted strong scientific evidence of the safety of vaccines. But, he said social media algorithms favor misinformation over facts. He added that such misinformation easily influences people who have not had a family member die from a preventable disease. Berkley said people must consider the belief in misinformation as a contagious sickness. He added, “This is a disease. This spreads at the speed of light, literally.” The World Health Organization says not enough people are getting the vaccine that prevents measles. It says this is why the disease is spreading around the world.