Published: Jun 15, 2011 6:50 PM EDT
Updated: Jun 15, 2011 6:50 PM EDT

ATLANTA - Health officials say that 118 cases of measles have been reported already this  year, that's the highest number of measles cases to be reported this early in  the year since 1996.

On Tuesday The Centers for Disease Control and Prevention released the count  for January 1 through May 20. Cases were seen in 23 states. None of the patients died, but about 40 percent were hospitalized.

The U.S. normally sees about 50 cases of measles in a year, thanks to  vaccinations. About 90 percent of the cases this year were unvaccinated.

Measles is highly contagious and up to 90 percent of people exposed to an  infected person get sick. The virus spreads easily through the air, and in  closed rooms, infected droplets can linger for up to two hours.