MIAMI — Two recent outbreaks of measles in the United States highlight the need for vaccination and vigilance for infections imported from overseas, including Europe, according to Dr. Carol J. Baker.
“How could this happen in 2008? We need to be aware of the importations from Europe,” Dr. Baker said. “Most people do not think of MMR as a travel vaccine. There is a lot of measles in Europe now, and people think of going to Europe as the same as [traveling within] the U.S.”
The Centers for Disease Control and Prevention reported both outbreaks in February 2008. In one instance, 11 cases in San Diego County in January and February of this year were linked to a 7-year-old unvaccinated boy who was infected during a family trip to Switzerland (MMWR 2008;57:203–6). None of the eight children he subsequently infected was vaccinated, including two siblings, two playmates from school, and four children exposed in a pediatrician's office (three were infants younger than the immunization age). Another three students at the school were secondarily infected. About 10% of the children at his school, including those infected, were vaccine personal belief exemptors (PEDIATRIC NEWS, March 2008, p. 14).
“If you have more and more vaccine exemptors, you will be as a community more susceptible to measles,” Dr. Baker said during a pediatric update sponsored by Miami Children's Hospital. No vaccinated child exposed to the San Diego index case became infected.
Suspect measles infection for all patients who have traveled overseas and present with a fever and rash, Dr. Baker advised. In addition, “separate a suspected case from the waiting room. You will need to clean the room very well and wait a few hours [before reentering].”
An earlier outbreak of measles in August-September 2007 also was imported and associated with an unvaccinated youth. The index case was a 12-year-old boy from Japan attending an International Youth event in Pennsylvania (MMWR 2008;57:169–73). A multistate investigation identified seven additional measles infections in Pennsylvania, Michigan, and Texas, including six confirmed from the index case using genetic sequencing.
Estimated attendance at the event was 265,000 and included teams from Canada, Chinese Taipei, Curaçao, Japan, the Netherlands, Mexico, Saudi Arabia, and Venezuela. The coaches and boys aged 10–13 years were housed in the same compound during the event, according to the CDC report.
“If you hear one of your patients is going to one of these events, make sure they are vaccinated,” said Dr. Baker, professor of pediatrics and molecular neurology and microbiology at Baylor College of Medicine, Houston.
“This outbreak highlights the need to maintain the highest possible vaccination coverage in the United States, along with disease surveillance and outbreak-containment capabilities,” the CDC investigators wrote.
One of the lessons learned from the outbreaks is that unvaccinated people are at high risk, Dr. Baker said. Measles spreads rapidly in susceptible populations and is still endemic throughout the world, including Europe.
A meeting attendee asked for advice regarding parents who refuse immunizations. “Personal exemptors are a big problem for pediatricians and family physicians. Look to the academy for advice. The child's parents in the case I presented had refused to vaccinate,” said Dr. Baker, who is also associate editor of the Red Book 2006: Report of the Committee on Infectious Diseases.
Another editor of the Red Book, Dr. David W. Kimberlin, responded during a panel discussion at the meeting. “There is a growing voice from parents whose children have died of vaccine-preventable diseases,” said Dr. Kimberlin, professor of pediatrics at the University of Alabama at Birmingham.
These groups can be a good resource, he said.
Measles is no longer endemic in the United States. In 2006, there were fewer than 100 cases reported to the CDC, and all were imported, primarily from India and Japan, with some cases from Europe.
At press time, the CDC reported that from January through April 25, 2008, 64 reports of confirmed measles cases were received from nine states, in which outbreaks were ongoing in four (Arizona, Michigan, New York, and Wisconsin). A total of 59 cases occurred among U.S. residents, and 54 were associated with the importation of measles from other countries. In all but one case, patients were unvaccinated or had unknown vaccination status. In all, 43 (67%) of the patients were less than 19 years of age and 32 (50%) were less than 4 years old.
When the San Diego boy presented on Jan. 25, 2008, with rash, fever, yellow discharge, and red lips, his family physician and pediatrician suspected scarlet fever. This diagnosis was ruled out on the basis of a negative rapid test for streptococcus. “If you've seen measles, it can be clearly differentiated, [but] younger physicians do not recognize this diagnosis in the United States,” Dr. Baker said.