This World Health Organization map shows the percent of the population vaccinated for measles in each country in 2013. Dark green is at least 90 percent. Light green is 80 to 89 percent. Orange is 50 to 79 percent. Red is less than 50 percent.
Courtesy of WHO
The KinderCare Learning Center in Palatine, Ill., where five infants have been diagnosed with measles. Officials are trying to track down the source of the infection.
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Leah Russin, of Palo Alto, Calif., holds her son, Leo, 16 months, as she speaks Wednesday at a news conference in support of proposed state legislation that would require parents to vaccinate all school children.