Year-to-date, there have been 288 cases of measles reported to the Centers for Disease Control and Prevention (CDC), the largest number in the U.S. recorded in the first five months of a year since 1994. “Measles in the U.S. has reached a 20 year high,” said Dr. Anne Schuchat, assistant surgeon general and director of CDC’s National Center for Immunization and Respiratory Diseases, who noted during a conference call that this “should be a wake-up call to parents,” since a full 90 percent of all cases were in people who had not been vaccinated or whose vaccination status was unknown.

Measles is highly contagious; it starts with a fever, causes a cough, runny nose, red eyes, and finally a rash of tiny, red spots. Although no deaths have been reported, the most common complication has been pneumonia among those patients recovering in the 18 states reporting cases. What is surprising about the current outbreak is that more than half (52 percent) of all cases were among patients older than 20. Those affected ranged in age from 2 weeks to 25 years. The acute viral illness can lead to serious complications and even death.

Outbreak in Ohio

Schuchat explained that 15 outbreaks — three or more related cases — have been reported. The largest outbreak is in Ohio, where multiple Amish communities imported the measles virus from the Philippines, where health authorities have confirmed 6,016 of nearly 26,014 suspected cases, including 41 deaths, between Jan. 1 and April 20 of this year. “It’s coming in on airplanes,” Schuchat said, noting that 97 percent of the American infections have been associated with importation via Amish community members who visited the Philippines during service missions.

Measles are still common in many parts of the world, though the U.S. eliminated measles in 2000; at that time, there had been no spread for more than 12 months. Elimination is a “fragile state,” Schuchat said, while measles exist in other parts of the world. “Today’s report reminds us that many adults who never received the vaccination are traveling the world and acquiring the disease,” said Schuchat, who suggested travelers review their vaccination history before leaving the country.

Vaccination Recommendations

CDC recommends infants receive one dose of the measles-mumps-rubella (MMR) vaccine at 12 to 15 months, followed by a second dose at 4 to 6 years. The MMR vaccine is both safe and effective, Schuchat said. For infants who are 6 to 11 months, the CDC recommends a single dose of the vaccination before traveling internationally. Less than one percent of toddlers nationwide do not get any vaccines; Schuchat said the CDC is not worried "that there’s a national upward swing in people not getting measles vaccines."

“If you are an adult and can’t remember if you got the vaccine or had the measles, go get vaccinated,” Schuchat said. More specifically, she said that it is likely adults born before 1957 had measles. Still, a second vaccination would not cause harm. For adults born after that year, the CDC’s routine recommendation is one dose of the vaccination (excluding pregnant women or people who are immunosuppressed), whereas for high-risk adults — international travelers, caretakers of children, health care workers — the CDC recommends two doses.

Although measles has a distinct rash, the infection is increasingly rare, so many doctors have not personally encountered a case in years. “We’ve had to remind people what it looks like,” Schuchat said.