Measles cases reported in the United States are the highest they've been in 20 years, with the majority of cases involving unvaccinated U.S. residents traveling to countries with a high incidence of the disease, health authorities say.
At this point in the year, 288 measles cases have been reported to the Centers for Disease Control in Atlanta.
That's the highest number of reported cases for the first 5 months of a year since May of 1994, the agency said.
Ninety-seven percent involved unvaccinated persons returning from overseas travel, the CDC said.
"The current increase in measles cases is being driven by unvaccinated people, primarily U.S. residents, who got measles in other countries, brought the virus back to the United States and spread [it] to others in communities where many people are not vaccinated," said Dr. Anne Schuchat, director of CDC's National Center for Immunization and Respiratory Diseases.
A large number of cases have been recorded in Ohio involving "multiple Amish communities [that have] roots with travel to the Philippines," said Schuchat, who is also the U.S. Assistant Surgeon General.
A group of people from Christian Aid Ministries had returned from the Philippines earlier this year. Around 32,000 cases of measles and 41 deaths have been reported in an outbreak in the Philippines so far this year, she said.
The high number of U.S. cases should be a "wake-up" call, she said, and should prompt people unsure of their vaccination status to talk to their doctors about getting inoculated.
If a person does not know if they've been vaccinated or not, it's safe to receive another measles inoculation, she said. The only exception should be people with compromised immune systems or pregnant women, she added, since the measles vaccine does contain a live virus.
More than half the U.S. cases reported so far in this year have been in adults 20 years of age or older.
"We often think of measles as a childhood disease; today's report reminds us adults can get it, too," Schuchat said.
The most usual complication so far in the U.S. cases of the highly contagious respiratory disease has been pneumonia, she said.
"Fortunately, there have been no deaths."
After Ohio's 138 cases, the states with the largest number of reported outbreaks are California, with 60 cases, and New York with 26.
Measles remains a common disease in many parts of the globe, the CDC says, with high rates in countries in Asia, Africa, Europe and in the Pacific.
