Measles cases have hit a 20-year high in the United States, a troubling increase fueled by international travel by people who have not been vaccinated against the virus, the Centers for Disease Control and Prevention said on Thursday, Reuters reported.
Between Jan. 1 and May 23 of this year, 288 measles cases were reported to the federal health agency, the highest year-to-date total since 1994, officials said.
"This is not the kind of record we want to break, but should be a wake-up call to travelers and parents to make sure vaccinations are up to date," said Anne Schuchat, director of the CDC's National Center for Immunizations and Respiratory Diseases.
Home-grown measles in the United States was declared eliminated in 2000, but cases imported from patients traveling abroad continue to infect unvaccinated U.S. residents with the highly contagious respiratory disease, according to the CDC.
A large outbreak in the Philippines was connected to 138 cases this year involving Amish communities in Ohio, health officials said. In all, 18 states have reported measles cases this year.
Measles has caused 43 patients to be hospitalized in 2014 but no deaths, Schuchat said.
Unvaccinated residents in the United States provide a "welcome wagon" for measles imported from abroad, Schuchat said, noting the virus is still common in many parts of the world including Europe, Asia and Africa. The Philippines has reported more than 32,000 measles cases and 41 deaths from January to April 20, she said.
Eighty-five percent of the unvaccinated U.S. residents who contracted measles cited religious, philosophical or personal reasons for not getting immunized, the CDC said.
"It was not because they were too young or had medical reasons like leukemia," Schuchat said. "These outbreaks illustrate that clusters of people with like-minded beliefs who forgo vaccines can be susceptible to outbreaks when the virus in imported."
The CDC recommends that, starting at age 12 months, infants receive two doses of MMR (measles, mumps and rubella) vaccine. Infants aged 6 through 11 months old should receive one dose of MMR vaccine before international travel.
The health agency also recommends vaccination for adults who were not immunized as children or are unsure of their immunization history.