With the introduction of measles vaccines in the 1960s, this once-common disease became something many of us have never seen firsthand. According to the CDC, a measles outbreak is defined as 3 or more related cases. But when measles gets into a community that has lower vaccination rates, it spreads quickly and causes larger outbreaks, as happened earlier this year in the U.S..Decreasing vaccination rates play a part. One infected person can transmit measles to 12 to 18 people.”Statistics show if a small percentage of the population are not immunized with the measles vaccination, infections can occur and spread. Two vaccines are available in the U.S.: MMR (Measles, mumps and rubella) or MMRV (Measles, mumps, rubella and varicella, or chickenpox).