ATLANTA (AP) -- Last year was the worst year for measles in the U.S. in 15 years, health officials said Thursday.
There were 222 cases of measles, a large jump from the 60 or so seen in a typical year. Most of the cases last year were imported -- either by foreign visitors or by U.S. residents who picked up the virus overseas.
U.S. children have been getting vaccinated against the measles for about 50 years. But low vaccination rates in Europe and other places resulted in large outbreaks overseas last year.
So far this year, 27 U.S. cases have been reported and it's too early to gauge whether 2012 will be as bad as last year. But with large international events like the London Olympics coming up, health officials are urging everyone -- particularly international travelers -- to make sure they're fully vaccinated.
"For those of you traveling abroad, bring back memories and not measles," said Dr. Anne Schuchat of the Centers for Disease Control and Prevention.
Generally, the Americans who got measles last year were not vaccinated. At least two-thirds of the U.S. cases fell into that category, including 50 children whose parents got philosophical, religious or medical exemptions to skip the school vaccinations required by most states, CDC officials said.
The vaccine is considered very effective but a few vaccinated people still get infected.
Measles is highly contagious. The virus spreads easily through the air, and in closed rooms, infected droplets can linger for up to two hours after the sick person leaves.
It causes a fever, runny nose, cough and a rash all over the body. In rare cases, measles can be deadly, and is particularly dangerous for children. Infection can also cause pregnant women to have a miscarriage or premature birth.
No measles deaths were reported in the U.S. last year; the last one occurred in 2003. But about a third of the 2011 cases were hospitalized, and one child was touch-and-go for about a week before finally recovering, one CDC official said.
Officials traced 200 of last year's 222 cases to measles in another country, said Schuchat, director of the CDC's Office of Infectious Diseases. The largest outbreak was in the Minneapolis area where 21 cases were traced to a child who got sick after a trip to Kenya.
The last time the United States had more measles was in 1996, when 508 cases were reported.
Before the vaccine was available, nearly all children got measles by their 15th birthday and epidemics cycled through the nation every two to three years -- generally peaking in the late winter or spring. In those days, about 450 to 500 Americans died from measles each year.
Two doses of a measles-mumps-rubella vaccine are recommended for all children, including a first dose given around a child's first birthday and a second dose around the time of preschool. These vaccinations are believed to last for a lifetime. Children as young as 6 months can get a first dose if they're going to a country with measles outbreaks, health officials say.