The Centers for Disease Control and Prevention says measles are up 300% this year making 2011 the largest outbreak in the U.S. in 15 years.

Why the outbreak?  Many doctors says it's because some parents are choosing to not get their children vaccinated.

CDC explains the typical vaccination recommendations:

Measles is the most deadly of all childhood rash/fever illnesses. The disease
spreads very easily, so it is important to protect against infection. To prevent
measles, children (and some adults) should be vaccinated with the measles,
mumps, and rubella (MMR) vaccine. Two doses of this vaccine are needed for
complete protection. Children should be given the first dose of MMR vaccine at
12 to 15 months of age. The second dose can be given 4 weeks later, but is
usually given before the start of kindergarten at 4 to 6 years of age.

Vaccination has dramatically reduced the number of cases of measles in the U.S. today, but measles is still very common in many other countries.  Most outbreaks in the U.S. can be traced to U.S. travelers and people who are visiting from another country.  They unknowingly bring measles with them to the United States.

The odds of running across measles are still very slim, but if you are exposed to measles and you or your child are not vaccinated against it, your odds of catching it are very high since it is so contagious.  WZZM reports 90% of unvaccinated children who come in contact with measles will get it.

When you consider how serious measles can be, 1 in 1000 cases are fatal, why take the chance?

Here's more from the CDC.