An unvaccinated child died this week in the West Texas outbreak of measles, which involves more than 120 cases. A virologist weighs in on how people can protect themselves. (AP Video: Mary Conlon, Laura Bargfeld)

Measles is one of the world’s most contagious viruses. Here’s what to know and how to avoid it

An unvaccinated child died this week in the West Texas outbreak of measles, which involves more than 120 cases. A virologist weighs in on how people can protect themselves. (AP Video: Mary Conlon, Laura Bargfeld)