Nearly 130 people have been affected by measles in the largest U.S. outbreak of the virus since 1997. Last week, federal officials reported that 127 people in 15 different states have been infected - most of these people were not vaccinated. According to the U.S. Centers for Disease Control (CDC), the outbreak was started by people who became infected while traveling overseas and then returned to the U.S. and infected others.

Many parents decline to get their children vaccinated because they are afraid that the vaccine shots may cause autism or other medical conditions. However, public health officials have been stressing the importance of childhood immunizations. The most recent serious outbreak of measles in the United States occurred from 1989 to 1991, when 55,000 Americans were infected with measles, leading to 123 deaths.

According to the CDC, the countries implicated in the measles outbreak so far are Switzerland, Israel, Belgium, Italy, India, Germany, China, Pakistan, Russia, and the Phillippines. And, measles cases have been reported in Arizona, Arkansas, California, Georgia, Hawaii, Illinois, Louisiana, Michigan, Missouri, New York, New Mexico, Pennsylvania, Virginia, Wisconsin, Washington state, and Washington DC. Travelers who return from any of the implicated countries feeling ill might want to be examined by a physician to reduce the risk of passing the highly contagious measles virus on to someone else.