Measles is a viral illness that causes fever, runny nose, cough, conjunctivitis and a whole body red rash. Complications can be serious, including pneumonia, ear infections, encephalitis, even death.

A total of 129 cases of measles have already been reported across the U.S. this year (compared to only 54 cases in 2012). “Pockets” of measles have been reported in New York City (58 cases) and in North Carolina.

Most cases of measles in this country have been “imported” by people who traveled outside the U.S. and developed symptoms upon their return. Measles, like several other illnesses, has not been eradicated in many parts of the world.

Jet travel allows diseases to be easily imported; a single carrier on a plane can expose hundreds of others, who then can go on to expose even more people. The European Union alone has reported 8,500 cases of measles in the past 12 months.

Vaccines are the mainstay for infectious disease prevention. Children routinely receive an MMR (against mumps, measles, rubella) vaccine at ages 1 and 4 years. While very effective, 2 percent to 5 percent of those receiving the vaccine don’t respond to the first dose, and require the “booster” dose to be immune. Fortunately, 99 percent of those who get two 2 doses of the vaccine are immune.

Children under the age of 1 year, and kids and adults who have not been immunized (and have not had the disease) are at greatest risk for developing measles.

Measles is highly contagious (the virus is spread by respiratory droplets) and has an incubation period of 7-18 days. Those infected are contagious from four days before they develop the rash (typically when they’re diagnosed) and up to four days after the rash has resolved.

So, with everyone getting ready for school, what better time to make sure your child has been immunized? And if you’re traveling outside the U.S. with a child under the age of 1 year, check with your doctor and ask about having the child vaccinated early. The current measles outbreak may continue to spread unless your child is vaccinated.

Dr. Sue Hubbard is an award-winning pediatrician, medical editor and media host. Submit questions at www.kidsdr.com.