MMR — the modern combination vaccine against measles, mumps and rubella — provides stronger, longer-lasting protection against measles than the stand-alone measles vaccine typically given in the U.S. in the early 1960s. Eric Risberg/AP hide caption
Vaccine refusal
The multistate measles outbreak in 2015 led pediatricians in Scottsdale, Ariz., to warn patients they might be exposed during office visits. The state's medical associations oppose legislation that would make it easier for parents to opt out of school vaccinations for their kids. Tom Stathis/AP hide caption
Arizona Legislature Mulls Bills To Weaken Vaccination Requirements
A combination vaccine against measles, mumps and rubella protects kids against all three illnesses with one shot. Courtney Perry/The Washington Post/Getty Images hide caption
Measles is highly contagious, and it produces fever and rash in susceptible people who become infected. Hazel Appleton/Health Protection Agency Centre/Science Source hide caption
Why A Court Once Ordered Kids Vaccinated Against Their Parents' Will
Rhett Krawitt, 6, outside his school in Tiburon, Calif. Seven percent of the children in his school are not vaccinated. Courtesy of Carl Krawitt hide caption
False-color transmission electron micrograph of a field of whooping cough bacteria, Bordetella pertussis. A. Barry Dowsett/Science Source hide caption
There today, here tomorrow: A mother holds her child for a measles vaccination in Manila, Philippines, in January. Travelers are bringing measles from the Philippines to the United States. Noel Celis/AFP/Getty Images hide caption