Measles Cases in the US are at a 20-Year High. Thanks, Anti-Vaxxers.

| Thu May 29, 2014 8:07 PM EDT

New data released by the CDC on Thursday shows that 288 cases of measles have been reported in the US since the beginning of the year—a higher number than those seen in the first five months of any year since 1994. More than one in seven of this year's cases resulted in hospitalization.

As assistant surgeon general Dr. Anne Schuchat explained, "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 to others in communities where many people are not vaccinated." Several of the cases occurred after US residents traveled to the Philippines, where there has been a measles outbreak since October 2013.

According to the CDC press release, "90 percent of all measles cases in the United States were in people who were not vaccinated or whose vaccination status was unknown. Among the U.S. residents who were not vaccinated, 85 percent were religious, philosophical or personal reasons."

The data adds fuel to the ongoing debate about vaccines: though research from around the world consistently shows that vaccines work, some doctors continue to support opting out of immunizations, and in some states, more than five percent of kindergartners have nonmedical vaccine exemptions.

Measles chart